diff --git a/composer.json b/composer.json
index 59200c4..968efe2 100644
--- a/composer.json
+++ b/composer.json
@@ -4,14 +4,18 @@
     "license": "MIT",
     "keywords": ["dns"],
     "require": {
-        "php": ">=5.4.0"
+        "php": ">=7.0"
     },
     "autoload": {
         "psr-4": {
             "LibDNS\\": "src/"
-        }
+        },
+        "files": ["src/functions.php"]
     },
     "support": {
         "issues": "https://github.com/DaveRandom/LibDNS/issues"
+    },
+    "suggest": {
+        "ext-intl": "Required for IDN support"
     }
 }
diff --git a/examples/AQuery.php b/examples/AQuery.php
index 8ea7e0b..07df0e6 100644
--- a/examples/AQuery.php
+++ b/examples/AQuery.php
@@ -21,7 +21,7 @@
 use \LibDNS\Decoder\DecoderFactory;
 
 // Config
-$queryName      = 'google.com';
+$queryName      = 'faß.de';
 $serverIP       = '8.8.8.8';
 $requestTimeout = 3;
 
diff --git a/src/Decoder/Decoder.php b/src/Decoder/Decoder.php
index e8d32fe..f3158b5 100644
--- a/src/Decoder/Decoder.php
+++ b/src/Decoder/Decoder.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Decodes raw network data to Message objects
  *
@@ -13,24 +13,26 @@
  */
 namespace LibDNS\Decoder;
 
-use \LibDNS\Packets\PacketFactory;
-use \LibDNS\Packets\Packet;
-use \LibDNS\Messages\MessageFactory;
-use \LibDNS\Messages\Message;
-use \LibDNS\Records\QuestionFactory;
-use \LibDNS\Records\ResourceBuilder;
-use \LibDNS\Records\Types\Type;
-use \LibDNS\Records\Types\Anything;
-use \LibDNS\Records\Types\BitMap;
-use \LibDNS\Records\Types\Char;
-use \LibDNS\Records\Types\CharacterString;
-use \LibDNS\Records\Types\DomainName;
-use \LibDNS\Records\Types\IPv4Address;
-use \LibDNS\Records\Types\IPv6Address;
-use \LibDNS\Records\Types\Long;
-use \LibDNS\Records\Types\Short;
-use \LibDNS\Records\Types\Types;
-use \LibDNS\Records\Types\TypeBuilder;
+use LibDNS\Messages\Message;
+use LibDNS\Messages\MessageFactory;
+use LibDNS\Packets\Packet;
+use LibDNS\Packets\PacketFactory;
+use LibDNS\Records\Question;
+use LibDNS\Records\QuestionFactory;
+use LibDNS\Records\Resource;
+use LibDNS\Records\ResourceBuilder;
+use LibDNS\Records\Types\Anything;
+use LibDNS\Records\Types\BitMap;
+use LibDNS\Records\Types\Char;
+use LibDNS\Records\Types\CharacterString;
+use LibDNS\Records\Types\DomainName;
+use LibDNS\Records\Types\IPv4Address;
+use LibDNS\Records\Types\IPv6Address;
+use LibDNS\Records\Types\Long;
+use LibDNS\Records\Types\Short;
+use LibDNS\Records\Types\Type;
+use LibDNS\Records\Types\TypeBuilder;
+use LibDNS\Records\Types\Types;
 
 /**
  * Decodes raw network data to Message objects
@@ -94,7 +96,7 @@ public function __construct(
         ResourceBuilder $resourceBuilder,
         TypeBuilder $typeBuilder,
         DecodingContextFactory $decodingContextFactory,
-        $allowTrailingData = false
+        bool $allowTrailingData = true
     ) {
         $this->packetFactory = $packetFactory;
         $this->messageFactory = $messageFactory;
@@ -113,7 +115,7 @@ public function __construct(
      * @return string
      * @throws \UnexpectedValueException When the read operation does not result in the requested number of bytes
      */
-    private function readDataFromPacket(Packet $packet, $length)
+    private function readDataFromPacket(Packet $packet, int $length): string
     {
         if ($packet->getBytesRemaining() < $length) {
             throw new \UnexpectedValueException('Decode error: Incomplete packet (tried to read ' . $length . ' bytes from index ' . $packet->getPointer());
@@ -131,7 +133,7 @@ private function readDataFromPacket(Packet $packet, $length)
      */
     private function decodeHeader(DecodingContext $decodingContext, Message $message)
     {
-        $header = unpack('nid/nmeta/nqd/nan/nns/nar', $this->readDataFromPacket($decodingContext->getPacket(), 12));
+        $header = \unpack('nid/nmeta/nqd/nan/nns/nar', $this->readDataFromPacket($decodingContext->getPacket(), 12));
         if (!$header) {
             throw new \UnexpectedValueException('Decode error: Header unpack failed');
         }
@@ -140,10 +142,10 @@ private function decodeHeader(DecodingContext $decodingContext, Message $message
 
         $message->setType(($header['meta'] & 0b1000000000000000) >> 15);
         $message->setOpCode(($header['meta'] & 0b0111100000000000) >> 11);
-        $message->isAuthoritative(($header['meta'] & 0b0000010000000000) >> 10);
-        $message->isTruncated(($header['meta'] & 0b0000001000000000) >> 9);
-        $message->isRecursionDesired(($header['meta'] & 0b0000000100000000) >> 8);
-        $message->isRecursionAvailable(($header['meta'] & 0b0000000010000000) >> 7);
+        $message->isAuthoritative((bool)(($header['meta'] & 0b0000010000000000) >> 10));
+        $message->isTruncated((bool)(($header['meta'] & 0b0000001000000000) >> 9));
+        $message->isRecursionDesired((bool)(($header['meta'] & 0b0000000100000000) >> 8));
+        $message->isRecursionAvailable((bool)(($header['meta'] & 0b0000000010000000) >> 7));
         $message->setResponseCode($header['meta'] & 0b0000000000001111);
 
         $decodingContext->setExpectedQuestionRecords($header['qd']);
@@ -161,7 +163,7 @@ private function decodeHeader(DecodingContext $decodingContext, Message $message
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeAnything(DecodingContext $decodingContext, Anything $anything, $length)
+    private function decodeAnything(DecodingContext $decodingContext, Anything $anything, int $length): int
     {
         $anything->setValue($this->readDataFromPacket($decodingContext->getPacket(), $length));
 
@@ -177,7 +179,7 @@ private function decodeAnything(DecodingContext $decodingContext, Anything $anyt
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeBitMap(DecodingContext $decodingContext, BitMap $bitMap, $length)
+    private function decodeBitMap(DecodingContext $decodingContext, BitMap $bitMap, int $length): int
     {
         $bitMap->setValue($this->readDataFromPacket($decodingContext->getPacket(), $length));
 
@@ -192,9 +194,9 @@ private function decodeBitMap(DecodingContext $decodingContext, BitMap $bitMap,
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeChar(DecodingContext $decodingContext, Char $char)
+    private function decodeChar(DecodingContext $decodingContext, Char $char): int
     {
-        $value = unpack('C', $this->readDataFromPacket($decodingContext->getPacket(), 1))[1];
+        $value = \unpack('C', $this->readDataFromPacket($decodingContext->getPacket(), 1))[1];
         $char->setValue($value);
 
         return 1;
@@ -208,10 +210,10 @@ private function decodeChar(DecodingContext $decodingContext, Char $char)
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeCharacterString(DecodingContext $decodingContext, CharacterString $characterString)
+    private function decodeCharacterString(DecodingContext $decodingContext, CharacterString $characterString): int
     {
         $packet = $decodingContext->getPacket();
-        $length = ord($this->readDataFromPacket($packet, 1));
+        $length = \ord($this->readDataFromPacket($packet, 1));
         $characterString->setValue($this->readDataFromPacket($packet, $length));
 
         return $length + 1;
@@ -225,32 +227,32 @@ private function decodeCharacterString(DecodingContext $decodingContext, Charact
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeDomainName(DecodingContext $decodingContext, DomainName $domainName)
+    private function decodeDomainName(DecodingContext $decodingContext, DomainName $domainName): int
     {
         $packet = $decodingContext->getPacket();
-        $startIndex = '0x' . dechex($packet->getPointer());
+        $startIndex = '0x' . \dechex($packet->getPointer());
         $labelRegistry = $decodingContext->getLabelRegistry();
 
         $labels = [];
         $totalLength = 0;
 
-        while (++$totalLength && $length = ord($this->readDataFromPacket($packet, 1))) {
+        while (++$totalLength && $length = \ord($this->readDataFromPacket($packet, 1))) {
             $labelType = $length & 0b11000000;
 
             if ($labelType === 0b00000000) {
                 $index = $packet->getPointer() - 1;
                 $label = $this->readDataFromPacket($packet, $length);
 
-                array_unshift($labels, [$index, $label]);
+                \array_unshift($labels, [$index, $label]);
                 $totalLength += $length;
             } else if ($labelType === 0b11000000) {
-                $index = (($length & 0b00111111) << 8) | ord($this->readDataFromPacket($packet, 1));
+                $index = (($length & 0b00111111) << 8) | \ord($this->readDataFromPacket($packet, 1));
                 $ref = $labelRegistry->lookupLabel($index);
                 if ($ref === null) {
                     throw new \UnexpectedValueException('Decode error: Invalid compression pointer reference in domain name at position ' . $startIndex);
                 }
 
-                array_unshift($labels, $ref);
+                \array_unshift($labels, $ref);
                 $totalLength++;
 
                 break;
@@ -265,8 +267,8 @@ private function decodeDomainName(DecodingContext $decodingContext, DomainName $
 
         $result = [];
         foreach ($labels as $label) {
-            if (is_int($label[0])) {
-                array_unshift($result, $label[1]);
+            if (\is_int($label[0])) {
+                \array_unshift($result, $label[1]);
                 $labelRegistry->register($result, $label[0]);
             } else {
                 $result = $label;
@@ -285,9 +287,9 @@ private function decodeDomainName(DecodingContext $decodingContext, DomainName $
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeIPv4Address(DecodingContext $decodingContext, IPv4Address $ipv4Address)
+    private function decodeIPv4Address(DecodingContext $decodingContext, IPv4Address $ipv4Address): int
     {
-        $octets = unpack('C4', $this->readDataFromPacket($decodingContext->getPacket(), 4));
+        $octets = \unpack('C4', $this->readDataFromPacket($decodingContext->getPacket(), 4));
         $ipv4Address->setOctets($octets);
 
         return 4;
@@ -301,9 +303,9 @@ private function decodeIPv4Address(DecodingContext $decodingContext, IPv4Address
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeIPv6Address(DecodingContext $decodingContext, IPv6Address $ipv6Address)
+    private function decodeIPv6Address(DecodingContext $decodingContext, IPv6Address $ipv6Address): int
     {
-        $shorts = unpack('n8', $this->readDataFromPacket($decodingContext->getPacket(), 16));
+        $shorts = \unpack('n8', $this->readDataFromPacket($decodingContext->getPacket(), 16));
         $ipv6Address->setShorts($shorts);
 
         return 16;
@@ -317,9 +319,9 @@ private function decodeIPv6Address(DecodingContext $decodingContext, IPv6Address
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeLong(DecodingContext $decodingContext, Long $long)
+    private function decodeLong(DecodingContext $decodingContext, Long $long): int
     {
-        $value = unpack('N', $this->readDataFromPacket($decodingContext->getPacket(), 4))[1];
+        $value = \unpack('N', $this->readDataFromPacket($decodingContext->getPacket(), 4))[1];
         $long->setValue($value);
 
         return 4;
@@ -333,9 +335,9 @@ private function decodeLong(DecodingContext $decodingContext, Long $long)
      * @return int The number of packet bytes consumed by the operation
      * @throws \UnexpectedValueException When the packet data is invalid
      */
-    private function decodeShort(DecodingContext $decodingContext, Short $short)
+    private function decodeShort(DecodingContext $decodingContext, Short $short): int
     {
-        $value = unpack('n', $this->readDataFromPacket($decodingContext->getPacket(), 2))[1];
+        $value = \unpack('n', $this->readDataFromPacket($decodingContext->getPacket(), 2))[1];
         $short->setValue($value);
 
         return 2;
@@ -351,7 +353,7 @@ private function decodeShort(DecodingContext $decodingContext, Short $short)
      * @throws \UnexpectedValueException When the packet data is invalid
      * @throws \InvalidArgumentException When the Type subtype is unknown
      */
-    private function decodeType(DecodingContext $decodingContext, Type $type, $length)
+    private function decodeType(DecodingContext $decodingContext, Type $type, int $length): int
     {
         if ($type instanceof Anything) {
             $result = $this->decodeAnything($decodingContext, $type, $length);
@@ -372,7 +374,7 @@ private function decodeType(DecodingContext $decodingContext, Type $type, $lengt
         } else if ($type instanceof Short) {
             $result = $this->decodeShort($decodingContext, $type);
         } else {
-            throw new \InvalidArgumentException('Unknown Type ' . get_class($type));
+            throw new \InvalidArgumentException('Unknown Type ' . \get_class($type));
         }
 
         return $result;
@@ -385,12 +387,12 @@ private function decodeType(DecodingContext $decodingContext, Type $type, $lengt
      * @return \LibDNS\Records\Question
      * @throws \UnexpectedValueException When the record is invalid
      */
-    private function decodeQuestionRecord(DecodingContext $decodingContext)
+    private function decodeQuestionRecord(DecodingContext $decodingContext): Question
     {
         /** @var \LibDNS\Records\Types\DomainName $domainName */
         $domainName = $this->typeBuilder->build(Types::DOMAIN_NAME);
         $this->decodeDomainName($decodingContext, $domainName);
-        $meta = unpack('ntype/nclass', $this->readDataFromPacket($decodingContext->getPacket(), 4));
+        $meta = \unpack('ntype/nclass', $this->readDataFromPacket($decodingContext->getPacket(), 4));
 
         $question = $this->questionFactory->create($meta['type']);
         $question->setName($domainName);
@@ -407,12 +409,12 @@ private function decodeQuestionRecord(DecodingContext $decodingContext)
      * @throws \UnexpectedValueException When the record is invalid
      * @throws \InvalidArgumentException When a type subtype is unknown
      */
-    private function decodeResourceRecord(DecodingContext $decodingContext)
+    private function decodeResourceRecord(DecodingContext $decodingContext): Resource
     {
         /** @var \LibDNS\Records\Types\DomainName $domainName */
         $domainName = $this->typeBuilder->build(Types::DOMAIN_NAME);
         $this->decodeDomainName($decodingContext, $domainName);
-        $meta = unpack('ntype/nclass/Nttl/nlength', $this->readDataFromPacket($decodingContext->getPacket(), 10));
+        $meta = \unpack('ntype/nclass/Nttl/nlength', $this->readDataFromPacket($decodingContext->getPacket(), 10));
 
         $resource = $this->resourceBuilder->build($meta['type']);
         $resource->setName($domainName);
@@ -452,7 +454,7 @@ private function decodeResourceRecord(DecodingContext $decodingContext)
      * @throws \UnexpectedValueException When the packet data is invalid
      * @throws \InvalidArgumentException When a type subtype is unknown
      */
-    public function decode($data)
+    public function decode(string $data): Message
     {
         $packet = $this->packetFactory->create($data);
         $decodingContext = $this->decodingContextFactory->create($packet);
diff --git a/src/Decoder/DecoderFactory.php b/src/Decoder/DecoderFactory.php
index b063667..0e6e58e 100644
--- a/src/Decoder/DecoderFactory.php
+++ b/src/Decoder/DecoderFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Decoder objects
  *
@@ -43,7 +43,7 @@ class DecoderFactory
      * @param bool $allowTrailingData
      * @return Decoder
      */
-    public function create(TypeDefinitionManager $typeDefinitionManager = null, $allowTrailingData = false)
+    public function create(TypeDefinitionManager $typeDefinitionManager = null, bool $allowTrailingData = true): Decoder
     {
         $typeBuilder = new TypeBuilder(new TypeFactory);
 
diff --git a/src/Decoder/DecodingContext.php b/src/Decoder/DecodingContext.php
index 91ede93..817aef2 100644
--- a/src/Decoder/DecodingContext.php
+++ b/src/Decoder/DecodingContext.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Holds data associated with a decode operation
  *
@@ -72,7 +72,7 @@ public function __construct(Packet $packet, LabelRegistry $labelRegistry)
      *
      * @return \LibDNS\Packets\Packet
      */
-    public function getPacket()
+    public function getPacket(): Packet
     {
         return $this->packet;
     }
@@ -82,7 +82,7 @@ public function getPacket()
      *
      * @return \LibDNS\Packets\LabelRegistry
      */
-    public function getLabelRegistry()
+    public function getLabelRegistry(): LabelRegistry
     {
         return $this->labelRegistry;
     }
@@ -92,7 +92,7 @@ public function getLabelRegistry()
      *
      * @return int
      */
-    public function getExpectedQuestionRecords()
+    public function getExpectedQuestionRecords(): int
     {
         return $this->expectedQuestionRecords;
     }
@@ -102,9 +102,9 @@ public function getExpectedQuestionRecords()
      *
      * @param int $expectedQuestionRecords
      */
-    public function setExpectedQuestionRecords($expectedQuestionRecords)
+    public function setExpectedQuestionRecords(int $expectedQuestionRecords)
     {
-        $this->expectedQuestionRecords = (int) $expectedQuestionRecords;
+        $this->expectedQuestionRecords = $expectedQuestionRecords;
     }
 
     /**
@@ -112,7 +112,7 @@ public function setExpectedQuestionRecords($expectedQuestionRecords)
      *
      * @return int
      */
-    public function getExpectedAnswerRecords()
+    public function getExpectedAnswerRecords(): int
     {
         return $this->expectedAnswerRecords;
     }
@@ -122,9 +122,9 @@ public function getExpectedAnswerRecords()
      *
      * @param int $expectedAnswerRecords
      */
-    public function setExpectedAnswerRecords($expectedAnswerRecords)
+    public function setExpectedAnswerRecords(int $expectedAnswerRecords)
     {
-        $this->expectedAnswerRecords = (int) $expectedAnswerRecords;
+        $this->expectedAnswerRecords = $expectedAnswerRecords;
     }
 
     /**
@@ -132,7 +132,7 @@ public function setExpectedAnswerRecords($expectedAnswerRecords)
      *
      * @return int
      */
-    public function getExpectedAuthorityRecords()
+    public function getExpectedAuthorityRecords(): int
     {
         return $this->expectedAuthorityRecords;
     }
@@ -142,9 +142,9 @@ public function getExpectedAuthorityRecords()
      *
      * @param int $expectedAuthorityRecords
      */
-    public function setExpectedAuthorityRecords($expectedAuthorityRecords)
+    public function setExpectedAuthorityRecords(int $expectedAuthorityRecords)
     {
-        $this->expectedAuthorityRecords = (int) $expectedAuthorityRecords;
+        $this->expectedAuthorityRecords = $expectedAuthorityRecords;
     }
 
     /**
@@ -152,7 +152,7 @@ public function setExpectedAuthorityRecords($expectedAuthorityRecords)
      *
      * @return int
      */
-    public function getExpectedAdditionalRecords()
+    public function getExpectedAdditionalRecords(): int
     {
         return $this->expectedAdditionalRecords;
     }
@@ -162,8 +162,8 @@ public function getExpectedAdditionalRecords()
      *
      * @param int $expectedAdditionalRecords
      */
-    public function setExpectedAdditionalRecords($expectedAdditionalRecords)
+    public function setExpectedAdditionalRecords(int $expectedAdditionalRecords)
     {
-        $this->expectedAdditionalRecords = (int) $expectedAdditionalRecords;
+        $this->expectedAdditionalRecords = $expectedAdditionalRecords;
     }
 }
diff --git a/src/Decoder/DecodingContextFactory.php b/src/Decoder/DecodingContextFactory.php
index 12bacad..129860f 100644
--- a/src/Decoder/DecodingContextFactory.php
+++ b/src/Decoder/DecodingContextFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates DecodingContext objects
  *
@@ -31,7 +31,7 @@ class DecodingContextFactory
      * @param \LibDNS\Packets\Packet $packet The packet to be decoded
      * @return \LibDNS\Decoder\DecodingContext
      */
-    public function create(Packet $packet)
+    public function create(Packet $packet): DecodingContext
     {
         return new DecodingContext($packet, new LabelRegistry);
     }
diff --git a/src/Encoder/Encoder.php b/src/Encoder/Encoder.php
index 38b136e..f8bc7a2 100644
--- a/src/Encoder/Encoder.php
+++ b/src/Encoder/Encoder.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Encodes Message objects to raw network data
  *
@@ -67,7 +67,7 @@ public function __construct(PacketFactory $packetFactory, EncodingContextFactory
      * @return string
      * @throws \UnexpectedValueException When the header section is invalid
      */
-    private function encodeHeader(EncodingContext $encodingContext, Message $message)
+    private function encodeHeader(EncodingContext $encodingContext, Message $message): string
     {
         $header = [
             'id' => $message->getID(),
@@ -78,7 +78,7 @@ private function encodeHeader(EncodingContext $encodingContext, Message $message
             'ar' => $message->getAdditionalRecords()->count()
         ];
 
-        $header['meta'] |= $message->getType() << 16;
+        $header['meta'] |= $message->getType() << 15;
         $header['meta'] |= $message->getOpCode() << 11;
         $header['meta'] |= ((int) $message->isAuthoritative()) << 10;
         $header['meta'] |= ((int) $encodingContext->isTruncated()) << 9;
@@ -86,7 +86,7 @@ private function encodeHeader(EncodingContext $encodingContext, Message $message
         $header['meta'] |= ((int) $message->isRecursionAvailable()) << 7;
         $header['meta'] |= $message->getResponseCode();
 
-        return pack('n*', $header['id'], $header['meta'], $header['qd'], $header['an'], $header['ns'], $header['ar']);
+        return \pack('n*', $header['id'], $header['meta'], $header['qd'], $header['an'], $header['ns'], $header['ar']);
     }
 
     /**
@@ -95,7 +95,7 @@ private function encodeHeader(EncodingContext $encodingContext, Message $message
      * @param \LibDNS\Records\Types\Anything $anything
      * @return string
      */
-    private function encodeAnything(Anything $anything)
+    private function encodeAnything(Anything $anything): string
     {
         return $anything->getValue();
     }
@@ -106,7 +106,7 @@ private function encodeAnything(Anything $anything)
      * @param \LibDNS\Records\Types\BitMap $bitMap
      * @return string
      */
-    private function encodeBitMap(BitMap $bitMap)
+    private function encodeBitMap(BitMap $bitMap): string
     {
         return $bitMap->getValue();
     }
@@ -117,9 +117,9 @@ private function encodeBitMap(BitMap $bitMap)
      * @param \LibDNS\Records\Types\Char $char
      * @return string
      */
-    private function encodeChar(Char $char)
+    private function encodeChar(Char $char): string
     {
-        return chr($char->getValue());
+        return \chr($char->getValue());
     }
 
     /**
@@ -128,10 +128,10 @@ private function encodeChar(Char $char)
      * @param \LibDNS\Records\Types\CharacterString $characterString
      * @return string
      */
-    private function encodeCharacterString(CharacterString $characterString)
+    private function encodeCharacterString(CharacterString $characterString): string
     {
         $data = $characterString->getValue();
-        return chr(strlen($data)) . $data;
+        return \chr(\strlen($data)) . $data;
     }
 
     /**
@@ -141,7 +141,7 @@ private function encodeCharacterString(CharacterString $characterString)
      * @param \LibDNS\Encoder\EncodingContext $encodingContext
      * @return string
      */
-    private function encodeDomainName(DomainName $domainName, EncodingContext $encodingContext)
+    private function encodeDomainName(DomainName $domainName, EncodingContext $encodingContext): string
     {
         $packetIndex = $encodingContext->getPacket()->getLength() + 12;
         $labelRegistry = $encodingContext->getLabelRegistry();
@@ -151,19 +151,19 @@ private function encodeDomainName(DomainName $domainName, EncodingContext $encod
 
         if ($encodingContext->useCompression()) {
             do {
-                $part = implode('.', $labels);
+                $part = \implode('.', $labels);
                 $index = $labelRegistry->lookupIndex($part);
 
                 if ($index === null) {
                     $labelRegistry->register($part, $packetIndex);
 
-                    $label = array_shift($labels);
-                    $length = strlen($label);
+                    $label = \array_shift($labels);
+                    $length = \strlen($label);
 
-                    $result .= chr($length) . $label;
+                    $result .= \chr($length) . $label;
                     $packetIndex += $length + 1;
                 } else {
-                    $result .= pack('n', 0b1100000000000000 | $index);
+                    $result .= \pack('n', 0b1100000000000000 | $index);
                     break;
                 }
             } while($labels);
@@ -173,7 +173,7 @@ private function encodeDomainName(DomainName $domainName, EncodingContext $encod
             }
         } else {
             foreach ($labels as $label) {
-                $result .= chr(strlen($label)) . $label;
+                $result .= \chr(\strlen($label)) . $label;
             }
 
             $result .= "\x00";
@@ -188,10 +188,10 @@ private function encodeDomainName(DomainName $domainName, EncodingContext $encod
      * @param \LibDNS\Records\Types\IPv4Address $ipv4Address
      * @return string
      */
-    private function encodeIPv4Address(IPv4Address $ipv4Address)
+    private function encodeIPv4Address(IPv4Address $ipv4Address): string
     {
         $octets = $ipv4Address->getOctets();
-        return pack('C*', $octets[0], $octets[1], $octets[2], $octets[3]);
+        return \pack('C*', $octets[0], $octets[1], $octets[2], $octets[3]);
     }
 
     /**
@@ -200,10 +200,10 @@ private function encodeIPv4Address(IPv4Address $ipv4Address)
      * @param \LibDNS\Records\Types\IPv6Address $ipv6Address
      * @return string
      */
-    private function encodeIPv6Address(IPv6Address $ipv6Address)
+    private function encodeIPv6Address(IPv6Address $ipv6Address): string
     {
         $shorts = $ipv6Address->getShorts();
-        return pack('n*', $shorts[0], $shorts[1], $shorts[2], $shorts[3], $shorts[4], $shorts[5], $shorts[6], $shorts[7]);
+        return \pack('n*', $shorts[0], $shorts[1], $shorts[2], $shorts[3], $shorts[4], $shorts[5], $shorts[6], $shorts[7]);
     }
 
     /**
@@ -212,9 +212,9 @@ private function encodeIPv6Address(IPv6Address $ipv6Address)
      * @param \LibDNS\Records\Types\Long $long
      * @return string
      */
-    private function encodeLong(Long $long)
+    private function encodeLong(Long $long): string
     {
-        return pack('N', $long->getValue());
+        return \pack('N', $long->getValue());
     }
 
     /**
@@ -223,9 +223,9 @@ private function encodeLong(Long $long)
      * @param \LibDNS\Records\Types\Short $short
      * @return string
      */
-    private function encodeShort(Short $short)
+    private function encodeShort(Short $short): string
     {
-        return pack('n', $short->getValue());
+        return \pack('n', $short->getValue());
     }
 
     /**
@@ -235,7 +235,7 @@ private function encodeShort(Short $short)
      * @param \LibDNS\Records\Types\Type $type
      * @return string
      */
-    private function encodeType(EncodingContext $encodingContext, Type $type)
+    private function encodeType(EncodingContext $encodingContext, Type $type): string
     {
         if ($type instanceof Anything) {
             $result = $this->encodeAnything($type);
@@ -256,7 +256,7 @@ private function encodeType(EncodingContext $encodingContext, Type $type)
         } else if ($type instanceof Short) {
             $result = $this->encodeShort($type);
         } else {
-            throw new \InvalidArgumentException('Unknown Type ' . get_class($type));
+            throw new \InvalidArgumentException('Unknown Type ' . \get_class($type));
         }
 
         return $result;
@@ -273,9 +273,9 @@ private function encodeQuestionRecord(EncodingContext $encodingContext, Question
         if (!$encodingContext->isTruncated()) {
             $packet = $encodingContext->getPacket();
             $name = $this->encodeDomainName($record->getName(), $encodingContext);
-            $meta = pack('n*', $record->getType(), $record->getClass());
+            $meta = \pack('n*', $record->getType(), $record->getClass());
 
-            if (12 + $packet->getLength() + strlen($name) + 4 > 512) {
+            if (12 + $packet->getLength() + \strlen($name) + 4 > 512) {
                 $encodingContext->isTruncated(true);
             } else {
                 $packet->write($name);
@@ -301,9 +301,9 @@ private function encodeResourceRecord(EncodingContext $encodingContext, Resource
                 $data .= $this->encodeType($encodingContext, $field);
             }
 
-            $meta = pack('n2Nn', $record->getType(), $record->getClass(), $record->getTTL(), strlen($data));
+            $meta = \pack('n2Nn', $record->getType(), $record->getClass(), $record->getTTL(), \strlen($data));
 
-            if (12 + $packet->getLength() + strlen($name) + 10 + strlen($data) > 512) {
+            if (12 + $packet->getLength() + \strlen($name) + 10 + \strlen($data) > 512) {
                 $encodingContext->isTruncated(true);
             } else {
                 $packet->write($name);
@@ -320,7 +320,7 @@ private function encodeResourceRecord(EncodingContext $encodingContext, Resource
      * @param bool $compress Enable message compression
      * @return string
      */
-    public function encode(Message $message, $compress = true)
+    public function encode(Message $message, $compress = true): string
     {
         $packet = $this->packetFactory->create();
         $encodingContext = $this->encodingContextFactory->create($packet, $compress);
diff --git a/src/Encoder/EncoderFactory.php b/src/Encoder/EncoderFactory.php
index 1101ca5..5bd73f8 100644
--- a/src/Encoder/EncoderFactory.php
+++ b/src/Encoder/EncoderFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Encoder objects
  *
@@ -29,7 +29,7 @@ class EncoderFactory
      *
      * @return \LibDNS\Encoder\Encoder
      */
-    public function create()
+    public function create(): Encoder
     {
         return new Encoder(new PacketFactory, new EncodingContextFactory);
     }
diff --git a/src/Encoder/EncodingContext.php b/src/Encoder/EncodingContext.php
index cf1f4b0..ec862e7 100644
--- a/src/Encoder/EncodingContext.php
+++ b/src/Encoder/EncodingContext.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Holds data associated with an encode operation
  *
@@ -52,11 +52,11 @@ class EncodingContext
      * @param \LibDNS\Packets\LabelRegistry $labelRegistry
      * @param bool $compress
      */
-    public function __construct(Packet $packet, LabelRegistry $labelRegistry, $compress)
+    public function __construct(Packet $packet, LabelRegistry $labelRegistry, bool $compress)
     {
         $this->packet = $packet;
         $this->labelRegistry = $labelRegistry;
-        $this->compress = (bool) $compress;
+        $this->compress = $compress;
     }
 
     /**
@@ -64,7 +64,7 @@ public function __construct(Packet $packet, LabelRegistry $labelRegistry, $compr
      *
      * @return \LibDNS\Packets\Packet
      */
-    public function getPacket()
+    public function getPacket(): Packet
     {
         return $this->packet;
     }
@@ -74,7 +74,7 @@ public function getPacket()
      *
      * @return \LibDNS\Packets\LabelRegistry
      */
-    public function getLabelRegistry()
+    public function getLabelRegistry(): LabelRegistry
     {
         return $this->labelRegistry;
     }
@@ -84,7 +84,7 @@ public function getLabelRegistry()
      *
      * @return bool
      */
-    public function useCompression()
+    public function useCompression(): bool
     {
         return $this->compress;
     }
@@ -95,12 +95,12 @@ public function useCompression()
      * @param bool $truncate
      * @return bool
      */
-    public function isTruncated($truncate = null)
+    public function isTruncated(bool $truncate = null): bool
     {
         $result = $this->truncate;
 
         if ($truncate !== null) {
-            $this->truncate = (bool) $truncate;
+            $this->truncate = $truncate;
         }
 
         return $result;
diff --git a/src/Encoder/EncodingContextFactory.php b/src/Encoder/EncodingContextFactory.php
index 76f5abf..8642385 100644
--- a/src/Encoder/EncodingContextFactory.php
+++ b/src/Encoder/EncodingContextFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates EncodingContext objects
  *
@@ -32,7 +32,7 @@ class EncodingContextFactory
      * @param bool $compress Whether message compression is enabled
      * @return \LibDNS\Encoder\EncodingContext
      */
-    public function create(Packet $packet, $compress)
+    public function create(Packet $packet, bool $compress): EncodingContext
     {
         return new EncodingContext($packet, new LabelRegistry, $compress);
     }
diff --git a/src/Enumeration.php b/src/Enumeration.php
index 02ec46d..402e0c2 100644
--- a/src/Enumeration.php
+++ b/src/Enumeration.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Base class for enumerations to prevent instantiation
  *
@@ -20,9 +20,9 @@
  * @package LibDNS
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class Enumeration
+abstract class Enumeration
 {
-    final public function __construct()
+    final protected function __construct()
     {
         throw new \LogicException('Enumerations cannot be instantiated');
     }
diff --git a/src/Messages/Message.php b/src/Messages/Message.php
index 1667ebe..673ae3e 100644
--- a/src/Messages/Message.php
+++ b/src/Messages/Message.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a DNS protocol message
  *
@@ -13,6 +13,7 @@
  */
 namespace LibDNS\Messages;
 
+use LibDNS\Records\RecordCollection;
 use \LibDNS\Records\RecordCollectionFactory;
 use \LibDNS\Records\RecordTypes;
 
@@ -33,7 +34,7 @@ class Message
     /**
      * @var int Indicates the type of the message, can be indicated using the MessageTypes enum
      */
-    private $type;
+    private $type = -1;
 
     /**
      * @var int Message opcode, can be indicated using the MessageOpCodes enum
@@ -48,7 +49,7 @@ class Message
     /**
      * @var bool Whether the message is truncated
      */
-    private $truncated;
+    private $truncated = false;
 
     /**
      * @var bool Whether a query desires the server to recurse the lookup
@@ -92,7 +93,7 @@ class Message
      * @param int $type Value of the message type field
      * @throws \RangeException When the supplied message type is outside the valid range 0 - 1
      */
-    public function __construct(RecordCollectionFactory $recordCollectionFactory, $type = null)
+    public function __construct(RecordCollectionFactory $recordCollectionFactory, int $type = null)
     {
         $this->questionRecords = $recordCollectionFactory->create(RecordTypes::QUESTION);
         $this->answerRecords = $recordCollectionFactory->create(RecordTypes::RESOURCE);
@@ -109,7 +110,7 @@ public function __construct(RecordCollectionFactory $recordCollectionFactory, $t
      *
      * @return int
      */
-    public function getID()
+    public function getID(): int
     {
         return $this->id;
     }
@@ -120,9 +121,8 @@ public function getID()
      * @param int $id The new value
      * @throws \RangeException When the supplied value is outside the valid range 0 - 65535
      */
-    public function setID($id)
+    public function setID(int $id)
     {
-        $id = (int) $id;
         if ($id < 0 || $id > 65535) {
             throw new \RangeException('Message ID must be in the range 0 - 65535');
         }
@@ -135,7 +135,7 @@ public function setID($id)
      *
      * @return int
      */
-    public function getType()
+    public function getType(): int
     {
         return $this->type;
     }
@@ -146,9 +146,8 @@ public function getType()
      * @param int $type The new value
      * @throws \RangeException When the supplied value is outside the valid range 0 - 1
      */
-    public function setType($type)
+    public function setType(int $type)
     {
-        $type = (int) $type;
         if ($type < 0 || $type > 1) {
             throw new \RangeException('Message type must be in the range 0 - 1');
         }
@@ -161,7 +160,7 @@ public function setType($type)
      *
      * @return int
      */
-    public function getOpCode()
+    public function getOpCode(): int
     {
         return $this->opCode;
     }
@@ -172,9 +171,8 @@ public function getOpCode()
      * @param int $opCode The new value
      * @throws \RangeException When the supplied value is outside the valid range 0 - 15
      */
-    public function setOpCode($opCode)
+    public function setOpCode(int $opCode)
     {
-        $opCode = (int) $opCode;
         if ($opCode < 0 || $opCode > 15) {
             throw new \RangeException('Message opcode must be in the range 0 - 15');
         }
@@ -188,15 +186,15 @@ public function setOpCode($opCode)
      * @param bool $newValue The new value
      * @return bool The old value
      */
-    public function isAuthoritative($newValue = null)
+    public function isAuthoritative(bool $newValue = null): bool
     {
         $result = $this->authoritative;
 
         if ($newValue !== null) {
-            $this->authoritative = (bool) $newValue;
+            $this->authoritative = $newValue;
         }
 
-        return (bool) $result;
+        return $result;
     }
 
     /**
@@ -205,15 +203,15 @@ public function isAuthoritative($newValue = null)
      * @param bool $newValue The new value
      * @return bool The old value
      */
-    public function isTruncated($newValue = null)
+    public function isTruncated(bool $newValue = null): bool
     {
         $result = $this->truncated;
 
         if ($newValue !== null) {
-            $this->truncated = (bool) $newValue;
+            $this->truncated = $newValue;
         }
 
-        return (bool) $result;
+        return $result;
     }
 
     /**
@@ -222,15 +220,15 @@ public function isTruncated($newValue = null)
      * @param bool $newValue The new value
      * @return bool The old value
      */
-    public function isRecursionDesired($newValue = null)
+    public function isRecursionDesired(bool $newValue = null): bool
     {
         $result = $this->recursionDesired;
 
         if ($newValue !== null) {
-            $this->recursionDesired = (bool) $newValue;
+            $this->recursionDesired = $newValue;
         }
 
-        return (bool) $result;
+        return $result;
     }
 
     /**
@@ -239,15 +237,15 @@ public function isRecursionDesired($newValue = null)
      * @param bool $newValue The new value
      * @return bool The old value
      */
-    public function isRecursionAvailable($newValue = null)
+    public function isRecursionAvailable(bool $newValue = null): bool
     {
         $result = $this->recursionAvailable;
 
         if ($newValue !== null) {
-            $this->recursionAvailable = (bool) $newValue;
+            $this->recursionAvailable = $newValue;
         }
 
-        return (bool) $result;
+        return $result;
     }
 
     /**
@@ -255,7 +253,7 @@ public function isRecursionAvailable($newValue = null)
      *
      * @return int
      */
-    public function getResponseCode()
+    public function getResponseCode(): int
     {
         return $this->opCode;
     }
@@ -266,9 +264,8 @@ public function getResponseCode()
      * @param int $responseCode The new value
      * @throws \RangeException When the supplied value is outside the valid range 0 - 15
      */
-    public function setResponseCode($responseCode)
+    public function setResponseCode(int $responseCode)
     {
-        $responseCode = (int) $responseCode;
         if ($responseCode < 0 || $responseCode > 15) {
             throw new \RangeException('Message response code must be in the range 0 - 15');
         }
@@ -281,7 +278,7 @@ public function setResponseCode($responseCode)
      *
      * @return \LibDNS\Records\RecordCollection
      */
-    public function getQuestionRecords()
+    public function getQuestionRecords(): RecordCollection
     {
         return $this->questionRecords;
     }
@@ -291,7 +288,7 @@ public function getQuestionRecords()
      *
      * @return \LibDNS\Records\RecordCollection
      */
-    public function getAnswerRecords()
+    public function getAnswerRecords(): RecordCollection
     {
         return $this->answerRecords;
     }
@@ -301,7 +298,7 @@ public function getAnswerRecords()
      *
      * @return \LibDNS\Records\RecordCollection
      */
-    public function getAuthorityRecords()
+    public function getAuthorityRecords(): RecordCollection
     {
         return $this->authorityRecords;
     }
@@ -311,7 +308,7 @@ public function getAuthorityRecords()
      *
      * @return \LibDNS\Records\RecordCollection
      */
-    public function getAdditionalRecords()
+    public function getAdditionalRecords(): RecordCollection
     {
         return $this->additionalRecords;
     }
diff --git a/src/Messages/MessageFactory.php b/src/Messages/MessageFactory.php
index e393163..fd6e694 100644
--- a/src/Messages/MessageFactory.php
+++ b/src/Messages/MessageFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Factory which creates Message objects
  *
@@ -30,7 +30,7 @@ class MessageFactory
      * @param int $type Value of the message type field
      * @return \LibDNS\Messages\Message
      */
-    public function create($type = null)
+    public function create(int $type = null): Message
     {
         return new Message(new RecordCollectionFactory, $type);
     }
diff --git a/src/Messages/MessageOpCodes.php b/src/Messages/MessageOpCodes.php
index 54f8e1e..dc43096 100644
--- a/src/Messages/MessageOpCodes.php
+++ b/src/Messages/MessageOpCodes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible message opcodes
  *
@@ -22,7 +22,7 @@
  * @package Messages
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class MessageOpCodes extends Enumeration
+final class MessageOpCodes extends Enumeration
 {
     const QUERY = 0;
     const IQUERY = 1;
diff --git a/src/Messages/MessageResponseCodes.php b/src/Messages/MessageResponseCodes.php
index cf4f271..0faf1dc 100644
--- a/src/Messages/MessageResponseCodes.php
+++ b/src/Messages/MessageResponseCodes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible message response codes
  *
@@ -22,7 +22,7 @@
  * @package Messages
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class MessageResponseCodes extends Enumeration
+final class MessageResponseCodes extends Enumeration
 {
     const NO_ERROR = 0;
     const FORMAT_ERROR = 1;
diff --git a/src/Messages/MessageTypes.php b/src/Messages/MessageTypes.php
index f36c05a..437a1fd 100644
--- a/src/Messages/MessageTypes.php
+++ b/src/Messages/MessageTypes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible message types
  *
@@ -22,7 +22,7 @@
  * @package Messages
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class MessageTypes extends Enumeration
+final class MessageTypes extends Enumeration
 {
     const QUERY = 0;
     const RESPONSE = 1;
diff --git a/src/Packets/LabelRegistry.php b/src/Packets/LabelRegistry.php
index a836648..3d11852 100644
--- a/src/Packets/LabelRegistry.php
+++ b/src/Packets/LabelRegistry.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Maintains a list of the relationships between domain name labels and the first point at
  * which they appear in a packet
@@ -39,13 +39,13 @@ class LabelRegistry
      * @param string|string[] $labels
      * @param int $index
      */
-    public function register($labels, $index)
+    public function register($labels, int $index)
     {
-        if (is_array($labels)) {
+        if (\is_array($labels)) {
             $labelsArr = $labels;
-            $labelsStr = implode('.', $labels);
+            $labelsStr = \implode('.', $labels);
         } else {
-            $labelsArr = explode('.', $labels);
+            $labelsArr = \explode('.', $labels);
             $labelsStr = (string) $labels;
         }
 
@@ -62,9 +62,9 @@ public function register($labels, $index)
      * @param string $label
      * @return int|null
      */
-    public function lookupIndex($label)
+    public function lookupIndex(string $label)
     {
-        return isset($this->labels[$label]) ? $this->labels[$label] : null;
+        return $this->labels[$label] ?? null;
     }
 
     /**
@@ -73,8 +73,8 @@ public function lookupIndex($label)
      * @param int $index
      * @return string[]|null
      */
-    public function lookupLabel($index)
+    public function lookupLabel(int $index)
     {
-        return isset($this->indexes[$index]) ? $this->indexes[$index] : null;
+        return $this->indexes[$index] ?? null;
     }
 }
diff --git a/src/Packets/Packet.php b/src/Packets/Packet.php
index 3bd0570..19b64b1 100644
--- a/src/Packets/Packet.php
+++ b/src/Packets/Packet.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a raw network data packet
  *
@@ -42,10 +42,10 @@ class Packet
      *
      * @param string $data The initial packet raw data
      */
-    public function __construct($data = '')
+    public function __construct(string $data = '')
     {
-        $this->data = (string) $data;
-        $this->length = strlen($this->data);
+        $this->data = $data;
+        $this->length = \strlen($this->data);
     }
 
     /**
@@ -55,22 +55,21 @@ public function __construct($data = '')
      * @return string
      * @throws \OutOfBoundsException When the pointer position is invalid or the supplied length is negative
      */
-    public function read($length = null)
+    public function read(int $length = null): string
     {
         if ($this->pointer > $this->length) {
             throw new \OutOfBoundsException('Pointer position invalid');
         }
 
         if ($length === null) {
-            $result = substr($this->data, $this->pointer);
+            $result = \substr($this->data, $this->pointer);
             $this->pointer = $this->length;
         } else {
-            $length = (int) $length;
             if ($length < 0) {
                 throw new \OutOfBoundsException('Length must be a positive integer');
             }
 
-            $result = substr($this->data, $this->pointer, (int) $length);
+            $result = \substr($this->data, $this->pointer, $length);
             $this->pointer += $length;
         }
 
@@ -83,9 +82,9 @@ public function read($length = null)
      * @param string $data The data to append
      * @return int The number of bytes written
      */
-    public function write($data)
+    public function write(string $data): int
     {
-        $length = strlen($data);
+        $length = \strlen($data);
 
         $this->data .= $data;
         $this->length += $length;
@@ -106,7 +105,7 @@ public function reset()
      *
      * @return int
      */
-    public function getPointer()
+    public function getPointer(): int
     {
         return $this->pointer;
     }
@@ -116,7 +115,7 @@ public function getPointer()
      *
      * @return int
      */
-    public function getLength()
+    public function getLength(): int
     {
         return $this->length;
     }
@@ -126,7 +125,7 @@ public function getLength()
      *
      * @return int
      */
-    public function getBytesRemaining()
+    public function getBytesRemaining(): int
     {
         return $this->length - $this->pointer;
     }
diff --git a/src/Packets/PacketFactory.php b/src/Packets/PacketFactory.php
index 4e4566c..5ffad14 100644
--- a/src/Packets/PacketFactory.php
+++ b/src/Packets/PacketFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Packet objects
  *
@@ -28,7 +28,7 @@ class PacketFactory
      * @param string $data
      * @return \LibDNS\Packets\Packet
      */
-    public function create($data = '')
+    public function create(string $data = ''): Packet
     {
         return new Packet($data);
     }
diff --git a/src/Records/Question.php b/src/Records/Question.php
index 4c1580f..24bb05b 100644
--- a/src/Records/Question.php
+++ b/src/Records/Question.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a DNS question record
  *
@@ -30,7 +30,7 @@ class Question extends Record
      * @param \LibDNS\Records\Types\TypeFactory $typeFactory
      * @param int $type Resource type being requested, can be indicated using the ResourceQTypes enum
      */
-    public function __construct(TypeFactory $typeFactory, $type)
+    public function __construct(TypeFactory $typeFactory, int $type)
     {
         $this->typeFactory = $typeFactory;
         $this->type = $type;
diff --git a/src/Records/QuestionFactory.php b/src/Records/QuestionFactory.php
index edb7ca0..a0e0cb9 100644
--- a/src/Records/QuestionFactory.php
+++ b/src/Records/QuestionFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Question objects
  *
@@ -30,7 +30,7 @@ class QuestionFactory
      * @param int $type The resource type
      * @return \LibDNS\Records\Question
      */
-    public function create($type)
+    public function create(int $type): Question
     {
         return new Question(new TypeFactory, $type);
     }
diff --git a/src/Records/RData.php b/src/Records/RData.php
index 9f61196..3c71546 100644
--- a/src/Records/RData.php
+++ b/src/Records/RData.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents the RDATA section of a resource record
  *
@@ -23,7 +23,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class RData implements \Iterator, \Countable
+class RData implements \IteratorAggregate, \Countable
 {
     /**
      * @var \LibDNS\Records\Types\Type[] The items that make up the complex type
@@ -35,11 +35,6 @@ class RData implements \Iterator, \Countable
      */
     private $typeDef;
 
-    /**
-     * @var bool Whether the iteration pointer has more elements to yield
-     */
-    private $pointerValid = 0;
-
     /**
      * Constructor
      *
@@ -58,9 +53,9 @@ public function __construct(TypeDefinition $typeDef)
     public function __toString()
     {
         if ($handler = $this->typeDef->getToStringFunction()) {
-            $result = call_user_func_array($handler, $this->fields);
+            $result = \call_user_func_array($handler, $this->fields);
         } else {
-            $result = implode(',', $this->fields);
+            $result = \implode(',', $this->fields);
         }
 
         return $result;
@@ -73,7 +68,7 @@ public function __toString()
      * @return \LibDNS\Records\Types\Type
      * @throws \OutOfBoundsException When the supplied index does not refer to a valid field
      */
-    public function getField($index)
+    public function getField(int $index)
     {
         if (!isset($this->fields[$index])) {
             throw new \OutOfBoundsException('Index ' . $index . ' does not refer to a valid field');
@@ -89,7 +84,7 @@ public function getField($index)
      * @param \LibDNS\Records\Types\Type $value
      * @throws \InvalidArgumentException When the supplied index/value pair does not match the type definition
      */
-    public function setField($index, Type $value)
+    public function setField(int $index, Type $value)
     {
         if (!$this->typeDef->getFieldDefinition($index)->assertDataValid($value)) {
             throw new \InvalidArgumentException('The supplied value is not valid for the specified index');
@@ -105,7 +100,7 @@ public function setField($index, Type $value)
      * @return \LibDNS\Records\Types\Type
      * @throws \OutOfBoundsException When the supplied name does not refer to a valid field
      */
-    public function getFieldByName($name)
+    public function getFieldByName(string $name): Type
     {
         return $this->getField($this->typeDef->getFieldIndexByName($name));
     }
@@ -118,7 +113,7 @@ public function getFieldByName($name)
      * @throws \OutOfBoundsException When the supplied name does not refer to a valid field
      * @throws \InvalidArgumentException When the supplied value does not match the type definition
      */
-    public function setFieldByName($name, Type $value)
+    public function setFieldByName(string $name, Type $value)
     {
         $this->setField($this->typeDef->getFieldIndexByName($name), $value);
     }
@@ -128,56 +123,19 @@ public function setFieldByName($name, Type $value)
      *
      * @return \LibDNS\Records\TypeDefinitions\TypeDefinition
      */
-    public function getTypeDefinition()
+    public function getTypeDefinition(): TypeDefinition
     {
         return $this->typeDef;
     }
 
     /**
-     * Get the field indicated by the iteration pointer (Iterator interface)
-     *
-     * @return \LibDNS\Records\Types\Type
-     */
-    public function current()
-    {
-        return current($this->fields);
-    }
-
-    /**
-     * Get the value of the iteration pointer (Iterator interface)
-     *
-     * @return int
-     */
-    public function key()
-    {
-        return key($this->fields);
-    }
-
-    /**
-     * Increment the iteration pointer (Iterator interface)
-     */
-    public function next()
-    {
-        $this->pointerValid = next($this->fields) !== false;
-    }
-
-    /**
-     * Reset the iteration pointer to the beginning (Iterator interface)
-     */
-    public function rewind()
-    {
-        reset($this->fields);
-        $this->pointerValid = count($this->fields) > 0;
-    }
-
-    /**
-     * Test whether the iteration pointer indicates a valid field (Iterator interface)
+     * Retrieve an iterator (IteratorAggregate interface)
      *
-     * @return bool
+     * @return \Iterator
      */
-    public function valid()
+    public function getIterator(): \Iterator
     {
-        return $this->pointerValid;
+        return new \ArrayIterator($this->fields);
     }
 
     /**
@@ -185,8 +143,8 @@ public function valid()
      *
      * @return int
      */
-    public function count()
+    public function count(): int
     {
-        return count($this->fields);
+        return \count($this->fields);
     }
 }
diff --git a/src/Records/RDataBuilder.php b/src/Records/RDataBuilder.php
index 6bebf00..b8734b5 100644
--- a/src/Records/RDataBuilder.php
+++ b/src/Records/RDataBuilder.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Builds RData objects from a type definition
  *
@@ -53,7 +53,7 @@ public function __construct(RDataFactory $rDataFactory, TypeBuilder $typeBuilder
      * @param \LibDNS\Records\TypeDefinitions\TypeDefinition $typeDefinition
      * @return \LibDNS\Records\RData
      */
-    public function build(TypeDefinition $typeDefinition)
+    public function build(TypeDefinition $typeDefinition): RData
     {
         $rData = $this->rDataFactory->create($typeDefinition);
 
diff --git a/src/Records/RDataFactory.php b/src/Records/RDataFactory.php
index 133e869..7b60cda 100644
--- a/src/Records/RDataFactory.php
+++ b/src/Records/RDataFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates RData objects
  *
@@ -30,7 +30,7 @@ class RDataFactory
      * @param \LibDNS\Records\TypeDefinitions\TypeDefinition $typeDefinition
      * @return \LibDNS\Records\RData
      */
-    public function create(TypeDefinition $typeDefinition)
+    public function create(TypeDefinition $typeDefinition): RData
     {
         return new RData($typeDefinition);
     }
diff --git a/src/Records/Record.php b/src/Records/Record.php
index ec9a97a..cf0b909 100644
--- a/src/Records/Record.php
+++ b/src/Records/Record.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a DNS record
  *
@@ -49,7 +49,7 @@ abstract class Record
      *
      * @return \LibDNS\Records\Types\DomainName
      */
-    public function getName()
+    public function getName(): DomainName
     {
         return $this->name;
     }
@@ -63,7 +63,7 @@ public function getName()
     public function setName($name)
     {
         if (!($name instanceof DomainName)) {
-            $name = $this->typeFactory->createDomainName($name);
+            $name = $this->typeFactory->createDomainName((string)$name);
         }
 
         $this->name = $name;
@@ -74,7 +74,7 @@ public function setName($name)
      *
      * @return int
      */
-    public function getType()
+    public function getType(): int
     {
         return $this->type;
     }
@@ -84,7 +84,7 @@ public function getType()
      *
      * @return int
      */
-    public function getClass()
+    public function getClass(): int
     {
         return $this->class;
     }
@@ -95,9 +95,8 @@ public function getClass()
      * @param int $class The new value, can be indicated using the ResourceClasses/ResourceQClasses enums
      * @throws \RangeException When the supplied value is outside the valid range 0 - 65535
      */
-    public function setClass($class)
+    public function setClass(int $class)
     {
-        $class = (int) $class;
         if ($class < 0 || $class > 65535) {
             throw new \RangeException('Record class must be in the range 0 - 65535');
         }
diff --git a/src/Records/RecordCollection.php b/src/Records/RecordCollection.php
index a0de99a..c7f434e 100644
--- a/src/Records/RecordCollection.php
+++ b/src/Records/RecordCollection.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Collection of Record objects
  *
@@ -20,7 +20,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class RecordCollection implements \Iterator, \Countable
+class RecordCollection implements \IteratorAggregate, \Countable
 {
     /**
      * @var \LibDNS\Records\Record[] List of records held in the collection
@@ -42,11 +42,6 @@ class RecordCollection implements \Iterator, \Countable
      */
     private $type;
 
-    /**
-     * @var int Iteration pointer
-     */
-    private $position = 0;
-
     /**
      * Constructor
      *
@@ -86,7 +81,7 @@ private function removeFromNameMap(Record $record)
         if (!empty($this->nameMap[$name = (string) $record->getName()])) {
             foreach ($this->nameMap[$name] as $key => $item) {
                 if ($item === $record) {
-                    array_splice($this->nameMap[$name], $key, 1);
+                    \array_splice($this->nameMap[$name], $key, 1);
                     break;
                 }
             }
@@ -141,9 +136,9 @@ public function remove(Record $record)
      * @param bool $sameInstance Whether to perform strict comparisons in search
      * @return bool
      */
-    public function contains(Record $record, $sameInstance = false)
+    public function contains(Record $record, bool $sameInstance = false): bool
     {
-        return in_array($record, $this->records, (bool) $sameInstance);
+        return \in_array($record, $this->records, $sameInstance);
     }
 
     /**
@@ -152,9 +147,9 @@ public function contains(Record $record, $sameInstance = false)
      * @param string $name The name to match records against
      * @return \LibDNS\Records\Record[]
      */
-    public function getRecordsByName($name)
+    public function getRecordsByName(string $name): array
     {
-        return isset($this->nameMap[$name = strtolower($name)]) ? $this->nameMap[$name] : [];
+        return $this->nameMap[\strtolower($name)] ?? [];
     }
 
     /**
@@ -164,7 +159,7 @@ public function getRecordsByName($name)
      * @return \LibDNS\Records\Record
      * @throws \OutOfBoundsException When the supplied index does not refer to a valid record
      */
-    public function getRecordByIndex($index)
+    public function getRecordByIndex(int $index): Record
     {
         if (isset($this->records[$index])) {
             return $this->records[$index];
@@ -179,11 +174,11 @@ public function getRecordByIndex($index)
      * @param string $name The name to match records against
      * @return int The number of records removed
      */
-    public function clearRecordsByName($name)
+    public function clearRecordsByName(string $name): int
     {
         $count = 0;
 
-        if (isset($this->nameMap[$name = strtolower($name)])) {
+        if (isset($this->nameMap[$name = \strtolower($name)])) {
             unset($this->nameMap[$name]);
 
             foreach ($this->records as $index => $record) {
@@ -193,7 +188,7 @@ public function clearRecordsByName($name)
                 }
             }
 
-            $this->records = array_values($this->records);
+            $this->records = \array_values($this->records);
         }
 
         return $count;
@@ -205,7 +200,7 @@ public function clearRecordsByName($name)
     public function clear()
     {
         $this->records = $this->nameMap = [];
-        $this->length = $this->position = 0;
+        $this->length = 0;
     }
 
     /**
@@ -213,9 +208,9 @@ public function clear()
      *
      * @return string[]
      */
-    public function getNames()
+    public function getNames(): array
     {
-        return array_keys($this->nameMap);
+        return \array_keys($this->nameMap);
     }
 
     /**
@@ -223,60 +218,19 @@ public function getNames()
      *
      * @return int
      */
-    public function getType()
+    public function getType(): int
     {
         return $this->type;
     }
 
     /**
-     * Get the record indicated by the iteration pointer (Iterator interface)
-     *
-     * @return \LibDNS\Records\Record
-     * @throws \OutOfBoundsException When the pointer does not refer to a valid record
-     */
-    public function current()
-    {
-        if (!isset($this->records[$this->position])) {
-            throw new \OutOfBoundsException('The current pointer position is invalid');
-        }
-
-        return $this->records[$this->position];
-    }
-
-    /**
-     * Get the value of the iteration pointer (Iterator interface)
-     *
-     * @return int
-     */
-    public function key()
-    {
-        return $this->position;
-    }
-
-    /**
-     * Increment the iteration pointer (Iterator interface)
-     */
-    public function next()
-    {
-        $this->position++;
-    }
-
-    /**
-     * Reset the iteration pointer to the beginning (Iterator interface)
-     */
-    public function rewind()
-    {
-        $this->position = 0;
-    }
-
-    /**
-     * Test whether the iteration pointer indicates a valid record (Iterator interface)
+     * Retrieve an iterator (IteratorAggregate interface)
      *
-     * @return bool
+     * @return \Iterator
      */
-    public function valid()
+    public function getIterator(): \Iterator
     {
-        return isset($this->records[$this->position]);
+        return new \ArrayIterator($this->records);
     }
 
     /**
@@ -284,7 +238,7 @@ public function valid()
      *
      * @return int
      */
-    public function count()
+    public function count(): int
     {
         return $this->length;
     }
diff --git a/src/Records/RecordCollectionFactory.php b/src/Records/RecordCollectionFactory.php
index 9f18840..95428fe 100644
--- a/src/Records/RecordCollectionFactory.php
+++ b/src/Records/RecordCollectionFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates RecordCollection objects
  *
@@ -29,7 +29,7 @@ class RecordCollectionFactory
      * @return \LibDNS\Records\RecordCollection
      * @throws \InvalidArgumentException When the specified record type is invalid
      */
-    public function create($type)
+    public function create(int $type): RecordCollection
     {
         return new RecordCollection($type);
     }
diff --git a/src/Records/RecordTypes.php b/src/Records/RecordTypes.php
index c81f3eb..f81a1e4 100644
--- a/src/Records/RecordTypes.php
+++ b/src/Records/RecordTypes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible record types
  *
@@ -22,7 +22,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class RecordTypes extends Enumeration
+final class RecordTypes extends Enumeration
 {
     const QUESTION = 0;
     const RESOURCE = 1;
diff --git a/src/Records/Resource.php b/src/Records/Resource.php
index 1404e0a..471d385 100644
--- a/src/Records/Resource.php
+++ b/src/Records/Resource.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a DNS resource record
  *
@@ -41,7 +41,7 @@ class Resource extends Record
      * @param int $type Can be indicated using the ResourceTypes enum
      * @param \LibDNS\Records\RData $data
      */
-    public function __construct(TypeFactory $typeFactory, $type, $data)
+    public function __construct(TypeFactory $typeFactory, int $type, RData $data)
     {
         $this->typeFactory = $typeFactory;
         $this->type = $type;
@@ -53,7 +53,7 @@ public function __construct(TypeFactory $typeFactory, $type, $data)
      *
      * @return int
      */
-    public function getTTL()
+    public function getTTL(): int
     {
         return $this->ttl;
     }
@@ -64,9 +64,8 @@ public function getTTL()
      * @param int $ttl The new value
      * @throws \RangeException When the supplied value is outside the valid range 0 - 4294967296
      */
-    public function setTTL($ttl)
+    public function setTTL(int $ttl)
     {
-        $ttl = (int) $ttl;
         if ($ttl < 0 || $ttl > 4294967296) {
             throw new \RangeException('Record class must be in the range 0 - 4294967296');
         }
@@ -79,7 +78,7 @@ public function setTTL($ttl)
      *
      * @return \LibDNS\Records\RData
      */
-    public function getData()
+    public function getData(): RData
     {
         return $this->data;
     }
diff --git a/src/Records/ResourceBuilder.php b/src/Records/ResourceBuilder.php
index 8addc4a..93e021e 100644
--- a/src/Records/ResourceBuilder.php
+++ b/src/Records/ResourceBuilder.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Builds Resource objects of a specific type
  *
@@ -59,7 +59,7 @@ public function __construct(ResourceFactory $resourceFactory, RDataBuilder $rDat
      * @param int $type Type of the resource, can be indicated using the ResourceTypes enum
      * @return \LibDNS\Records\Resource
      */
-    public function build($type)
+    public function build(int $type): Resource
     {
         $typeDefinition = $this->typeDefinitionManager->getTypeDefinition($type);
         $rData = $this->rDataBuilder->build($typeDefinition);
diff --git a/src/Records/ResourceBuilderFactory.php b/src/Records/ResourceBuilderFactory.php
index 3c7ec1d..1bac743 100644
--- a/src/Records/ResourceBuilderFactory.php
+++ b/src/Records/ResourceBuilderFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates ResourceBuilder objects
  *
@@ -34,7 +34,7 @@ class ResourceBuilderFactory
      * @param \LibDNS\Records\TypeDefinitions\TypeDefinitionManager $typeDefinitionManager
      * @return \LibDNS\Records\ResourceBuilder
      */
-    public function create(TypeDefinitionManager $typeDefinitionManager = null)
+    public function create(TypeDefinitionManager $typeDefinitionManager = null): ResourceBuilder
     {
         return new ResourceBuilder(
             new ResourceFactory,
diff --git a/src/Records/ResourceClasses.php b/src/Records/ResourceClasses.php
index cc1e056..53853dd 100644
--- a/src/Records/ResourceClasses.php
+++ b/src/Records/ResourceClasses.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible resource CLASS values
  *
@@ -22,7 +22,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class ResourceClasses extends Enumeration
+abstract class ResourceClasses extends Enumeration
 {
     const IN = 1;
     const CS = 2;
diff --git a/src/Records/ResourceFactory.php b/src/Records/ResourceFactory.php
index 72456aa..627a7f7 100644
--- a/src/Records/ResourceFactory.php
+++ b/src/Records/ResourceFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Resource objects
  *
@@ -31,7 +31,7 @@ class ResourceFactory
      * @param \LibDNS\Records\RData $data
      * @return \LibDNS\Records\Resource
      */
-    public function create($type, $data)
+    public function create(int $type, RData $data): Resource
     {
         return new Resource(new TypeFactory, $type, $data);
     }
diff --git a/src/Records/ResourceQClasses.php b/src/Records/ResourceQClasses.php
index 82f2e2f..e75a102 100644
--- a/src/Records/ResourceQClasses.php
+++ b/src/Records/ResourceQClasses.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible resource QCLASS values
  *
@@ -20,7 +20,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class ResourceQClasses extends ResourceClasses
+final class ResourceQClasses extends ResourceClasses
 {
     const ANY = 255;
 }
diff --git a/src/Records/ResourceQTypes.php b/src/Records/ResourceQTypes.php
index 7eccc77..dc00042 100644
--- a/src/Records/ResourceQTypes.php
+++ b/src/Records/ResourceQTypes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible resource QTYPE values
  *
@@ -20,7 +20,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class ResourceQTypes extends ResourceTypes
+final class ResourceQTypes extends ResourceTypes
 {
     const AXFR = 252;
     const MAILB = 253;
diff --git a/src/Records/ResourceTypes.php b/src/Records/ResourceTypes.php
index ccb7955..60f9717 100644
--- a/src/Records/ResourceTypes.php
+++ b/src/Records/ResourceTypes.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of possible resource TYPE values
  *
@@ -22,7 +22,7 @@
  * @package Records
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class ResourceTypes extends Enumeration
+abstract class ResourceTypes extends Enumeration
 {
     const A          = 1;
     const AAAA       = 28;
diff --git a/src/Records/TypeDefinitions/FieldDefinition.php b/src/Records/TypeDefinitions/FieldDefinition.php
index e15a0a0..df304a5 100644
--- a/src/Records/TypeDefinitions/FieldDefinition.php
+++ b/src/Records/TypeDefinitions/FieldDefinition.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Defines a field in a type
  *
@@ -68,13 +68,13 @@ class FieldDefinition
      * @param bool $allowsMultiple
      * @param int $minimumValues
      */
-    public function __construct($index, $name, $type, $allowsMultiple, $minimumValues)
+    public function __construct(int $index, string $name, int $type, bool $allowsMultiple, int $minimumValues)
     {
-        $this->index = (int) $index;
-        $this->name = (string) $name;
-        $this->type = (int) $type;
-        $this->allowsMultiple = (bool) $allowsMultiple;
-        $this->minimumValues = (int) $minimumValues;
+        $this->index = $index;
+        $this->name = $name;
+        $this->type = $type;
+        $this->allowsMultiple = $allowsMultiple;
+        $this->minimumValues = $minimumValues;
     }
 
     /**
@@ -82,7 +82,7 @@ public function __construct($index, $name, $type, $allowsMultiple, $minimumValue
      *
      * @return int
      */
-    public function getIndex()
+    public function getIndex(): int
     {
         return $this->index;
     }
@@ -92,7 +92,7 @@ public function getIndex()
      *
      * @return string
      */
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -102,7 +102,7 @@ public function getName()
      *
      * @return int
      */
-    public function getType()
+    public function getType(): int
     {
         return $this->type;
     }
@@ -112,7 +112,7 @@ public function getType()
      *
      * @return bool
      */
-    public function allowsMultiple()
+    public function allowsMultiple(): bool
     {
         return $this->allowsMultiple;
     }
@@ -122,7 +122,7 @@ public function allowsMultiple()
      *
      * @return int
      */
-    public function getMinimumValues()
+    public function getMinimumValues(): int
     {
         return $this->minimumValues;
     }
@@ -133,7 +133,7 @@ public function getMinimumValues()
      * @param \LibDNS\Records\Types\Type
      * @return bool
      */
-    public function assertDataValid(Type $value)
+    public function assertDataValid(Type $value): bool
     {
         return (($this->type & Types::ANYTHING)         && $value instanceof Anything)
             || (($this->type & Types::BITMAP)           && $value instanceof BitMap)
diff --git a/src/Records/TypeDefinitions/FieldDefinitionFactory.php b/src/Records/TypeDefinitions/FieldDefinitionFactory.php
index df28529..afd2b1e 100644
--- a/src/Records/TypeDefinitions/FieldDefinitionFactory.php
+++ b/src/Records/TypeDefinitions/FieldDefinitionFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates FieldDefinition objects
  *
@@ -32,7 +32,7 @@ class FieldDefinitionFactory
      * @param int $minimumValues
      * @return \LibDNS\Records\TypeDefinitions\FieldDefinition
      */
-    public function create($index, $name, $type, $allowsMultiple, $minimumValues)
+    public function create(int $index, string $name, int $type, bool $allowsMultiple, int $minimumValues): FieldDefinition
     {
         return new FieldDefinition($index, $name, $type, $allowsMultiple, $minimumValues);
     }
diff --git a/src/Records/TypeDefinitions/TypeDefinition.php b/src/Records/TypeDefinitions/TypeDefinition.php
index ba66edf..e448114 100644
--- a/src/Records/TypeDefinitions/TypeDefinition.php
+++ b/src/Records/TypeDefinitions/TypeDefinition.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Defines a data type comprising multiple fields
  *
@@ -20,7 +20,7 @@
  * @package TypeDefinitions
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class TypeDefinition implements \Iterator, \Countable
+class TypeDefinition implements \IteratorAggregate, \Countable
 {
     /**
      * @var FieldDefinitionFactory Creates FieldDefinition objects
@@ -52,11 +52,6 @@ class TypeDefinition implements \Iterator, \Countable
      */
     private $toStringFunction;
 
-    /**
-     * @var bool Whether the iteration pointer indicates a valid item
-     */
-    private $pointerValid = true;
-
     /**
      * Constructor
      *
@@ -69,7 +64,7 @@ public function __construct(FieldDefinitionFactory $fieldDefFactory, array $defi
         $this->fieldDefFactory = $fieldDefFactory;
 
         if (isset($definition['__toString'])) {
-            if (!is_callable($definition['__toString'])) {
+            if (!\is_callable($definition['__toString'])) {
                 throw new \InvalidArgumentException('Invalid type definition: __toString() implementation is not callable');
             }
 
@@ -77,7 +72,7 @@ public function __construct(FieldDefinitionFactory $fieldDefFactory, array $defi
             unset($definition['__toString']);
         }
 
-        $this->fieldCount = count($definition);
+        $this->fieldCount = \count($definition);
         $index = 0;
         foreach ($definition as $name => $type) {
             $this->registerField($index++, $name, $type);
@@ -92,9 +87,9 @@ public function __construct(FieldDefinitionFactory $fieldDefFactory, array $defi
      * @param int $type
      * @throws \InvalidArgumentException When the field definition is invalid
      */
-    private function registerField($index, $name, $type)
+    private function registerField(int $index, string $name, int $type)
     {
-        if (!preg_match('/^(?P<name>[\w\-]+)(?P<quantifier>\+|\*)?(?P<minimum>(?<=\+)\d+)?$/', strtolower($name), $matches)) {
+        if (!\preg_match('/^(?P<name>[\w\-]+)(?P<quantifier>\+|\*)?(?P<minimum>(?<=\+)\d+)?$/', \strtolower($name), $matches)) {
             throw new \InvalidArgumentException('Invalid field definition ' . $name . ': Syntax error');
         }
 
@@ -129,9 +124,8 @@ private function registerField($index, $name, $type)
      * @return \LibDNS\Records\TypeDefinitions\FieldDefinition
      * @throws \OutOfBoundsException When the supplied index does not refer to a valid field
      */
-    public function getFieldDefinition($index)
+    public function getFieldDefinition(int $index): FieldDefinition
     {
-        $index = (int) $index;
         if (isset($this->fieldDefs[$index])) {
             $fieldDef = $this->fieldDefs[$index];
         } else if ($index >= 0 && $this->lastField->allowsMultiple()) {
@@ -150,9 +144,9 @@ public function getFieldDefinition($index)
      * @return int
      * @throws \OutOfBoundsException When the supplied name does not refer to a valid field
      */
-    public function getFieldIndexByName($name)
+    public function getFieldIndexByName($name): int
     {
-        $fieldName = strtolower($name);
+        $fieldName = \strtolower($name);
         if (!isset($this->fieldNameMap[$fieldName])) {
             throw new \OutOfBoundsException('Name ' . $name . ' does not refer to a valid field');
         }
@@ -181,50 +175,13 @@ public function setToStringFunction(callable $function)
     }
 
     /**
-     * Get the field indicated by the iteration pointer (Iterator interface)
-     *
-     * @return \LibDNS\Records\TypeDefinitions\FieldDefinition
-     */
-    public function current()
-    {
-        return current($this->fieldDefs);
-    }
-
-    /**
-     * Get the key indicated by the iteration pointer
-     *
-     * @return int
-     */
-    public function key()
-    {
-        return key($this->fieldDefs);
-    }
-
-    /**
-     * Increment the iteration pointer (Iterator interface)
-     */
-    public function next()
-    {
-        $this->pointerValid = next($this->fieldDefs) !== false;
-    }
-
-    /**
-     * Reset the iteration pointer to the beginning (Iterator interface)
-     */
-    public function rewind()
-    {
-        reset($this->fieldDefs);
-        $this->pointerValid = count($this->fieldDefs) > 0;
-    }
-
-    /**
-     * Test whether the iteration pointer indicates a valid field (Iterator interface)
+     * Retrieve an iterator (IteratorAggregate interface)
      *
-     * @return bool
+     * @return \Iterator
      */
-    public function valid()
+    public function getIterator(): \Iterator
     {
-        return $this->pointerValid;
+        return new \ArrayIterator($this->fieldDefs);
     }
 
     /**
@@ -232,7 +189,7 @@ public function valid()
      *
      * @return int
      */
-    public function count()
+    public function count(): int
     {
         return $this->fieldCount;
     }
diff --git a/src/Records/TypeDefinitions/TypeDefinitionFactory.php b/src/Records/TypeDefinitions/TypeDefinitionFactory.php
index 0aede80..18cc00c 100644
--- a/src/Records/TypeDefinitions/TypeDefinitionFactory.php
+++ b/src/Records/TypeDefinitions/TypeDefinitionFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates TypeDefinition objects
  *
@@ -30,7 +30,7 @@ class TypeDefinitionFactory
      * @return \LibDNS\Records\TypeDefinitions\TypeDefinition
      * @throws \InvalidArgumentException When the type definition is invalid
      */
-    public function create(FieldDefinitionFactory $fieldDefinitionFactory, array $definition)
+    public function create(FieldDefinitionFactory $fieldDefinitionFactory, array $definition): TypeDefinition
     {
         return new TypeDefinition($fieldDefinitionFactory, $definition);
     }
diff --git a/src/Records/TypeDefinitions/TypeDefinitionManager.php b/src/Records/TypeDefinitions/TypeDefinitionManager.php
index 2cdf036..be4da0a 100644
--- a/src/Records/TypeDefinitions/TypeDefinitionManager.php
+++ b/src/Records/TypeDefinitions/TypeDefinitionManager.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Holds data about how the RDATA sections of known resource record types are structured
  *
@@ -244,10 +244,8 @@ private function setDefinitions()
      * @param int $recordType Resource type, can be indicated using the ResourceTypes enum
      * @return \LibDNS\Records\TypeDefinitions\TypeDefinition
      */
-    public function getTypeDefinition($recordType)
+    public function getTypeDefinition(int $recordType)
     {
-        $recordType = (int) $recordType;
-
         if (!isset($this->typeDefs[$recordType])) {
             $definition = isset($this->definitions[$recordType]) ? $this->definitions[$recordType] : ['data' => Types::ANYTHING];
             $this->typeDefs[$recordType] = $this->typeDefFactory->create($this->fieldDefFactory, $definition);
@@ -263,16 +261,16 @@ public function getTypeDefinition($recordType)
      * @param int[]|\LibDNS\Records\TypeDefinitions\TypeDefinition $definition
      * @throws \InvalidArgumentException When the type definition is invalid
      */
-    public function registerTypeDefinition($recordType, $definition)
+    public function registerTypeDefinition(int $recordType, $definition)
     {
         if (!($definition instanceof TypeDefinition)) {
-            if (!is_array($definition)) {
+            if (!\is_array($definition)) {
                 throw new \InvalidArgumentException('Definition must be an array or an instance of ' . __NAMESPACE__ . '\TypeDefinition');
             }
 
-            $definition = (int) $this->typeDefFactory->create($this->fieldDefFactory, $definition);
+            $definition = $this->typeDefFactory->create($this->fieldDefFactory, $definition);
         }
 
-        $this->typeDefs[(int) $recordType] = $definition;
+        $this->typeDefs[$recordType] = $definition;
     }
 }
diff --git a/src/Records/TypeDefinitions/TypeDefinitionManagerFactory.php b/src/Records/TypeDefinitions/TypeDefinitionManagerFactory.php
index d2a219b..4107de7 100644
--- a/src/Records/TypeDefinitions/TypeDefinitionManagerFactory.php
+++ b/src/Records/TypeDefinitions/TypeDefinitionManagerFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates TypeDefinitionManager objects
  *
@@ -27,7 +27,7 @@ class TypeDefinitionManagerFactory
      *
      * @return \LibDNS\Records\TypeDefinitions\TypeDefinitionManager
      */
-    public function create()
+    public function create(): TypeDefinitionManager
     {
         return new TypeDefinitionManager(new TypeDefinitionFactory, new FieldDefinitionFactory);
     }
diff --git a/src/Records/Types/Anything.php b/src/Records/Types/Anything.php
index d3e9593..8ea45ab 100644
--- a/src/Records/Types/Anything.php
+++ b/src/Records/Types/Anything.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a generic binary data string
  *
@@ -35,8 +35,9 @@ class Anything extends Type
      */
     public function setValue($value)
     {
-        $value = (string) $value;
-        if (strlen($value) > 65535) {
+        $value = (string)$value;
+
+        if (\strlen($value) > 65535) {
             throw new \UnexpectedValueException('Untyped string length must be in the range 0 - 65535');
         }
 
diff --git a/src/Records/Types/BitMap.php b/src/Records/Types/BitMap.php
index 41c237e..a10c72c 100644
--- a/src/Records/Types/BitMap.php
+++ b/src/Records/Types/BitMap.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a bit map
  *
@@ -34,7 +34,7 @@ class BitMap extends Type
      */
     public function setValue($value)
     {
-        $this->value = (string) $value;
+        $this->value = (string)$value;
     }
 
     /**
@@ -44,22 +44,22 @@ public function setValue($value)
      * @param bool $newValue The new value
      * @return bool The old value
      */
-    public function isBitSet($index, $newValue = null)
+    public function isBitSet(int $index, bool $newValue = null): bool
     {
         $charIndex = (int)($index / 8);
         $bitMask = 0b10000000 >> ($index % 8);
 
         $result = false;
         if (isset($this->value[$charIndex])) {
-            $result = (bool) (ord($this->value[$charIndex]) & $bitMask);
+            $result = (bool) (\ord($this->value[$charIndex]) & $bitMask);
         }
 
         if (isset($newValue) && $newValue != $result) {
             if (!isset($this->value[$charIndex])) {
-                $this->value = str_pad($this->value, $charIndex + 1, "\x00", STR_PAD_RIGHT);
+                $this->value = \str_pad($this->value, $charIndex + 1, "\x00", STR_PAD_RIGHT);
             }
 
-            $this->value[$charIndex] = chr((ord($this->value[$charIndex]) & ~$bitMask) | ($newValue ? $bitMask : 0));
+            $this->value[$charIndex] = \chr((\ord($this->value[$charIndex]) & ~$bitMask) | ($newValue ? $bitMask : 0));
         }
 
         return $result;
diff --git a/src/Records/Types/Char.php b/src/Records/Types/Char.php
index 577cdaa..aa0c51e 100644
--- a/src/Records/Types/Char.php
+++ b/src/Records/Types/Char.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents an 8-bit unsigned integer
  *
@@ -30,13 +30,14 @@ class Char extends Type
     /**
      * Set the internal value
      *
-     * @param int $value The new value
+     * @param string $value The new value
      * @throws \UnderflowException When the supplied value is less than 0
      * @throws \OverflowException When the supplied value is greater than 255
      */
     public function setValue($value)
     {
         $value = (int) $value;
+
         if ($value < 0) {
             throw new \UnderflowException('Char value must be in the range 0 - 255');
         } else if ($value > 255) {
diff --git a/src/Records/Types/CharacterString.php b/src/Records/Types/CharacterString.php
index 2a2b2d7..1b55fc2 100644
--- a/src/Records/Types/CharacterString.php
+++ b/src/Records/Types/CharacterString.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a binary character string
  *
@@ -35,8 +35,9 @@ class CharacterString extends Type
      */
     public function setValue($value)
     {
-        $value = (string) $value;
-        if (strlen($value) > 255) {
+        $value = (string)$value;
+
+        if (\strlen($value) > 255) {
             throw new \UnexpectedValueException('Character string length must be in the range 0 - 255');
         }
 
diff --git a/src/Records/Types/DomainName.php b/src/Records/Types/DomainName.php
index fba3fbe..d9b1a8f 100644
--- a/src/Records/Types/DomainName.php
+++ b/src/Records/Types/DomainName.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a fully qualified domain name
  *
@@ -42,12 +42,10 @@ class DomainName extends Type
      */
     public function __construct($value = null)
     {
-        if (isset($value)) {
-            if (is_array($value)) {
-                $this->setLabels($value);
-            } else {
-                $this->setValue($value);
-            }
+        if (\is_array($value)) {
+            $this->setLabels($value);
+        } else {
+            parent::__construct($value);
         }
     }
 
@@ -59,7 +57,7 @@ public function __construct($value = null)
      */
     public function setValue($value)
     {
-        $this->setLabels(explode('.', $value));
+        $this->setLabels(\explode('.', (string)$value));
     }
 
     /**
@@ -68,9 +66,9 @@ public function setValue($value)
      * @param bool $tldFirst Whether to return the label list ordered with the TLD label first
      * @return string[]
      */
-    public function getLabels($tldFirst = false)
+    public function getLabels($tldFirst = false): array
     {
-        return $tldFirst ? array_reverse($this->labels) : $this->labels;
+        return $tldFirst ? \array_reverse($this->labels) : $this->labels;
     }
 
     /**
@@ -89,12 +87,12 @@ public function setLabels(array $labels, $tldFirst = false)
         $length = $count = 0;
 
         foreach ($labels as &$label) {
-            $labelLength = strlen($label);
+            $label = \LibDNS\normalize_name($label);
+            $labelLength = \strlen($label);
             if ($labelLength > 63) {
                 throw new \InvalidArgumentException('Label list is not a valid domain name: Label ' . $label . ' length exceeds 63 byte limit');
             }
             $length += $labelLength + 1;
-            $label = strtolower($label);
             $count++;
         }
 
@@ -107,7 +105,7 @@ public function setLabels(array $labels, $tldFirst = false)
             throw new \InvalidArgumentException('Label list is not a valid domain name: Total length exceeds 255 byte limit');
         }
 
-        $this->labels = $tldFirst ? array_reverse($labels) : $labels;
-        $this->value = implode('.', $this->labels);
+        $this->labels = $tldFirst ? \array_reverse($labels) : $labels;
+        $this->value = \implode('.', $this->labels);
     }
 }
diff --git a/src/Records/Types/IPv4Address.php b/src/Records/Types/IPv4Address.php
index 88c2c67..66657f4 100644
--- a/src/Records/Types/IPv4Address.php
+++ b/src/Records/Types/IPv4Address.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents an IPv4 address
  *
@@ -40,12 +40,10 @@ class IPv4Address extends Type
      */
     public function __construct($value = null)
     {
-        if (isset($value)) {
-            if (is_array($value)) {
-                $this->setOctets($value);
-            } else {
-                $this->setValue($value);
-            }
+        if (\is_array($value)) {
+            $this->setOctets($value);
+        } else {
+            parent::__construct($value);
         }
     }
 
@@ -57,7 +55,7 @@ public function __construct($value = null)
      */
     public function setValue($value)
     {
-        $this->setOctets(explode('.', $value));
+        $this->setOctets(\explode('.', (string)$value));
     }
 
     /**
@@ -65,7 +63,7 @@ public function setValue($value)
      *
      * @return int[]
      */
-    public function getOctets()
+    public function getOctets(): array
     {
         return $this->octets;
     }
@@ -78,19 +76,19 @@ public function getOctets()
      */
     public function setOctets(array $octets)
     {
-        if (count($octets) !== 4) {
+        if (\count($octets) !== 4) {
             throw new \UnexpectedValueException('Octet list is not a valid IPv4 address: invalid octet count');
         }
 
         foreach ($octets as &$octet) {
-            if (strspn((string)$octet, "0123456789") !== strlen($octet) || $octet < 0x00 || $octet > 0xff) {
+            if (\strspn((string)$octet, "0123456789") !== \strlen((string)$octet) || $octet < 0x00 || $octet > 0xff) {
                 throw new \UnexpectedValueException('Octet list is not a valid IPv4 address: invalid octet value ' . $octet);
             }
 
             $octet = (int) $octet;
         }
 
-        $this->octets = array_values($octets);
-        $this->value = implode('.', $this->octets);
+        $this->octets = \array_values($octets);
+        $this->value = \implode('.', $this->octets);
     }
 }
diff --git a/src/Records/Types/IPv6Address.php b/src/Records/Types/IPv6Address.php
index f6145ed..e2ca5af 100644
--- a/src/Records/Types/IPv6Address.php
+++ b/src/Records/Types/IPv6Address.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents an IPv6 address
  *
@@ -61,7 +61,7 @@ private function createCompressedString($shorts)
                 $currentPos = $currentLen = 0;
             }
 
-            $shorts[$i] = dechex($shorts[$i]);
+            $shorts[$i] = \dechex($shorts[$i]);
         }
         if ($inBlock) {
             $compressLen = $currentLen;
@@ -77,10 +77,10 @@ private function createCompressedString($shorts)
                 $replace = [''];
             }
 
-            array_splice($shorts, $compressPos, $compressLen, $replace);
+            \array_splice($shorts, $compressPos, $compressLen, $replace);
         }
 
-        return implode(':', $shorts);
+        return \implode(':', $shorts);
     }
 
     /**
@@ -91,12 +91,10 @@ private function createCompressedString($shorts)
      */
     public function __construct($value = null)
     {
-        if (isset($value)) {
-            if (is_array($value)) {
-                $this->setShorts($value);
-            } else {
-                $this->setValue($value);
-            }
+        if (\is_array($value)) {
+            $this->setShorts($value);
+        } else {
+            parent::__construct($value);
         }
     }
 
@@ -108,20 +106,20 @@ public function __construct($value = null)
      */
     public function setValue($value)
     {
-        $shorts = explode(':', (string) $value);
+        $shorts = \explode(':', (string)$value);
 
-        $count = count($shorts);
+        $count = \count($shorts);
         if ($count < 3 || $count > 8) {
             throw new \UnexpectedValueException('Value is not a valid IPv6 address: invalid short count');
         } else if ($shorts[0] === '' && $shorts[1] === '') {
-            $shorts = array_pad($shorts, -8, '0');
+            $shorts = \array_pad($shorts, -8, '0');
         } else if ($shorts[$count - 2] === '' && $shorts[$count - 1] === '') {
-            $shorts = array_pad($shorts, 8, '0');
-        } else if (false !== $pos = array_search('', $shorts, true)) {
-            array_splice($shorts, $pos, 1, array_fill(0, 8 - ($count - 1), '0'));
+            $shorts = \array_pad($shorts, 8, '0');
+        } else if (false !== $pos = \array_search('', $shorts, true)) {
+            \array_splice($shorts, $pos, 1, \array_fill(0, 8 - ($count - 1), '0'));
         }
 
-        $this->setShorts(array_map('hexdec', $shorts));
+        $this->setShorts(\array_map('hexdec', $shorts));
     }
 
     /**
@@ -129,7 +127,7 @@ public function setValue($value)
      *
      * @return int[]
      */
-    public function getShorts()
+    public function getShorts(): array
     {
         return $this->shorts;
     }
@@ -142,19 +140,19 @@ public function getShorts()
      */
     public function setShorts(array $shorts)
     {
-        if (count($shorts) !== 8) {
+        if (\count($shorts) !== 8) {
             throw new \UnexpectedValueException('Short list is not a valid IPv6 address: invalid short count');
         }
 
         foreach ($shorts as &$short) {
-            if (strspn((string)$short, "0123456789") !== strlen($short) || $short < 0x0000 || $short > 0xffff) {
+            if (\strspn((string)$short, "0123456789") !== \strlen($short) || $short < 0x0000 || $short > 0xffff) {
                 throw new \UnexpectedValueException('Short list is not a valid IPv6 address: invalid short value ' . $short);
             }
 
             $short = (int) $short;
         }
 
-        $this->shorts = array_values($shorts);
+        $this->shorts = \array_values($shorts);
         $this->value = $this->createCompressedString($this->shorts);
     }
 }
diff --git a/src/Records/Types/Long.php b/src/Records/Types/Long.php
index 64bdc05..5ba9361 100644
--- a/src/Records/Types/Long.php
+++ b/src/Records/Types/Long.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a 32-bit unsigned integer
  *
@@ -30,16 +30,17 @@ class Long extends Type
     /**
      * Set the internal value
      *
-     * @param int $value The new value
+     * @param string $value The new value
      * @throws \UnderflowException When the supplied value is less than 0
      * @throws \OverflowException When the supplied value is greater than 4294967296
      */
     public function setValue($value)
     {
-        $value = (int) $value;
+        $value = (int)$value;
+
         if ($value < 0) {
             throw new \UnderflowException('Long integer value must be in the range 0 - 4294967296');
-        } else if ($value > 4294967296) {
+        } else if ($value > 0xffffffff) {
             throw new \OverflowException('Long integer value must be in the range 0 - 4294967296');
         }
 
diff --git a/src/Records/Types/Short.php b/src/Records/Types/Short.php
index 2fb1f99..27a235a 100644
--- a/src/Records/Types/Short.php
+++ b/src/Records/Types/Short.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Represents a 16-bit unsigned integer
  *
@@ -30,16 +30,17 @@ class Short extends Type
     /**
      * Set the internal value
      *
-     * @param int $value The new value
+     * @param string $value The new value
      * @throws \UnderflowException When the supplied value is less than 0
      * @throws \OverflowException When the supplied value is greater than 65535
      */
     public function setValue($value)
     {
-        $value = (int) $value;
+        $value = (int)$value;
+
         if ($value < 0) {
             throw new \UnderflowException('Short integer value must be in the range 0 - 65535');
-        } else if ($value > 65535) {
+        } else if ($value > 0xffff) {
             throw new \OverflowException('Short integer value must be in the range 0 - 65535');
         }
 
diff --git a/src/Records/Types/Type.php b/src/Records/Types/Type.php
index 736d299..78e56e8 100644
--- a/src/Records/Types/Type.php
+++ b/src/Records/Types/Type.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Base class for simple data types
  *
@@ -30,10 +30,10 @@ abstract class Type
     /**
      * Constructor
      *
-     * @param mixed $value Internal value
+     * @param string $value Internal value
      * @throws \RuntimeException When the supplied value is invalid
      */
-    public function __construct($value = null)
+    public function __construct(string $value = null)
     {
         if (isset($value)) {
             $this->setValue($value);
@@ -41,11 +41,11 @@ public function __construct($value = null)
     }
 
     /**
-     * Magic method for type coersion to string
+     * Magic method for type coercion to string
      *
      * @return string
      */
-    public function __toString()
+    public function __toString(): string
     {
         return (string) $this->value;
     }
@@ -63,7 +63,7 @@ public function getValue()
     /**
      * Set the internal value
      *
-     * @param mixed $value The new value
+     * @param string $value The new value
      * @throws \RuntimeException When the supplied value is invalid
      */
     abstract public function setValue($value);
diff --git a/src/Records/Types/TypeBuilder.php b/src/Records/Types/TypeBuilder.php
index 12c7d21..f5a090f 100644
--- a/src/Records/Types/TypeBuilder.php
+++ b/src/Records/Types/TypeBuilder.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Builds Types from type definitions
  *
@@ -43,7 +43,7 @@ public function __construct(TypeFactory $typeFactory)
      * @param int $type Data type, can be indicated using the Types enum
      * @return \LibDNS\Records\Types\Type
      */
-    public function build($type)
+    public function build(int $type): Type
     {
         static $typeMap = [
             Types::ANYTHING         => 'createAnything',
diff --git a/src/Records/Types/TypeFactory.php b/src/Records/Types/TypeFactory.php
index 5685d9d..6f42359 100644
--- a/src/Records/Types/TypeFactory.php
+++ b/src/Records/Types/TypeFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Creates Type objects
  *
@@ -28,7 +28,7 @@ class TypeFactory
      * @param string $value
      * @return \LibDNS\Records\Types\Anything
      */
-    public function createAnything($value = null)
+    public function createAnything(string $value = null)
     {
         return new Anything($value);
     }
@@ -39,7 +39,7 @@ public function createAnything($value = null)
      * @param string $value
      * @return \LibDNS\Records\Types\BitMap
      */
-    public function createBitMap($value = null)
+    public function createBitMap(string $value = null)
     {
         return new BitMap($value);
     }
@@ -50,9 +50,9 @@ public function createBitMap($value = null)
      * @param int $value
      * @return \LibDNS\Records\Types\Char
      */
-    public function createChar($value = null)
+    public function createChar(int $value = null)
     {
-        return new Char($value);
+        return new Char((string)$value);
     }
 
     /**
@@ -61,7 +61,7 @@ public function createChar($value = null)
      * @param string $value
      * @return \LibDNS\Records\Types\CharacterString
      */
-    public function createCharacterString($value = null)
+    public function createCharacterString(string $value = null)
     {
         return new CharacterString($value);
     }
@@ -80,7 +80,7 @@ public function createDomainName($value = null)
     /**
      * Create a new IPv4Address object
      *
-     * @param string $value
+     * @param string|int[] $value
      * @return \LibDNS\Records\Types\IPv4Address
      */
     public function createIPv4Address($value = null)
@@ -91,7 +91,7 @@ public function createIPv4Address($value = null)
     /**
      * Create a new IPv6Address object
      *
-     * @param string $value
+     * @param string|int[] $value
      * @return \LibDNS\Records\Types\IPv6Address
      */
     public function createIPv6Address($value = null)
@@ -105,9 +105,9 @@ public function createIPv6Address($value = null)
      * @param int $value
      * @return \LibDNS\Records\Types\Long
      */
-    public function createLong($value = null)
+    public function createLong(int $value = null)
     {
-        return new Long($value);
+        return new Long((string)$value);
     }
 
     /**
@@ -116,8 +116,8 @@ public function createLong($value = null)
      * @param int $value
      * @return \LibDNS\Records\Types\Short
      */
-    public function createShort($value = null)
+    public function createShort(int $value = null)
     {
-        return new Short($value);
+        return new Short((string)$value);
     }
 }
diff --git a/src/Records/Types/Types.php b/src/Records/Types/Types.php
index 3e18be2..337cce1 100644
--- a/src/Records/Types/Types.php
+++ b/src/Records/Types/Types.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  * Enumeration of simple data types
  *
@@ -22,7 +22,7 @@
  * @package Types
  * @author Chris Wright <https://github.com/DaveRandom>
  */
-class Types extends Enumeration
+final class Types extends Enumeration
 {
     const ANYTHING         = 0b000000001;
     const BITMAP           = 0b000000010;
diff --git a/src/functions.php b/src/functions.php
new file mode 100644
index 0000000..cdb5ab2
--- /dev/null
+++ b/src/functions.php
@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace LibDNS;
+
+if (\function_exists('idn_to_ascii')) {
+    function normalize_name(string $label): string
+    {
+        if (false === $result = \idn_to_ascii($label, 0, INTL_IDNA_VARIANT_UTS46)) {
+            throw new \InvalidArgumentException("Label '{$label}' could not be processed for IDN");
+        }
+
+        return $result;
+    }
+} else {
+    function normalize_name(string $label): string
+    {
+        if (\preg_match('/[\x80-\xff]/', $label)) {
+            throw new \InvalidArgumentException(
+                "Label '{$label}' contains non-ASCII characters and IDN support is not available."
+                . " Verify that ext/intl is installed for IDN support."
+            );
+        }
+
+        return \strtolower($label);
+    }
+}