diff --git a/core/primitives/Cargo.toml b/core/primitives/Cargo.toml
index 85ecfa2067515..daecd6ef8055f 100644
--- a/core/primitives/Cargo.toml
+++ b/core/primitives/Cargo.toml
@@ -31,7 +31,7 @@ num-traits = { version = "0.2.8", default-features = false }
 zeroize = { version = "0.10.1", default-features = false }
 lazy_static = { version = "1.4.0", default-features = false, optional = true }
 parking_lot = { version = "0.9.0", optional = true }
-libsecp256k1 = { version = "0.3.0", optional = true }
+libsecp256k1 = { version = "0.3.0", default-features = false, optional = true }
 tiny-keccak = { version = "1.5.0", optional = true }
 substrate-debug-derive = { version = "2.0.0", path = "./debug-derive" }
 externalities = { package = "substrate-externalities", path = "../externalities", optional = true }
@@ -99,6 +99,8 @@ full_crypto = [
 	"ed25519-dalek",
 	"blake2-rfc",
 	"schnorrkel",
+	"libsecp256k1",
 	"hex",
+	"sha2",
 	"twox-hash"
 ]
diff --git a/core/primitives/src/crypto.rs b/core/primitives/src/crypto.rs
index 271b1839bb8d7..08c0a89af7842 100644
--- a/core/primitives/src/crypto.rs
+++ b/core/primitives/src/crypto.rs
@@ -257,6 +257,7 @@ pub enum PublicError {
 #[cfg(feature = "full_crypto")]
 pub trait Ss58Codec: Sized + AsMut<[u8]> + AsRef<[u8]> + Default {
 	/// Some if the string is a properly encoded SS58Check address.
+	#[cfg(feature = "std")]
 	fn from_ss58check(s: &str) -> Result<Self, PublicError> {
 		Self::from_ss58check_with_version(s)
 			.and_then(|(r, v)| match v {
@@ -269,6 +270,7 @@ pub trait Ss58Codec: Sized + AsMut<[u8]> + AsRef<[u8]> + Default {
 			})
 	}
 	/// Some if the string is a properly encoded SS58Check address.
+	#[cfg(feature = "std")]
 	fn from_ss58check_with_version(s: &str) -> Result<(Self, Ss58AddressFormat), PublicError> {
 		let mut res = Self::default();
 		let len = res.as_mut().len();
@@ -806,6 +808,7 @@ pub trait Pair: CryptoType + Sized + Clone + Send + Sync + 'static {
 	/// Interprets the string `s` in order to generate a key pair.
 	///
 	/// See [`from_string_with_seed`](Self::from_string_with_seed) for more extensive documentation.
+	#[cfg(feature = "std")]
 	fn from_string(s: &str, password_override: Option<&str>) -> Result<Self, SecretStringError> {
 		Self::from_string_with_seed(s, password_override).map(|x| x.0)
 	}
diff --git a/core/primitives/src/ecdsa.rs b/core/primitives/src/ecdsa.rs
index abff460c91034..691e9fba5e184 100644
--- a/core/primitives/src/ecdsa.rs
+++ b/core/primitives/src/ecdsa.rs
@@ -18,27 +18,31 @@
 //! Simple ECDSA API.
 // end::description[]
 
+use rstd::vec::Vec;
+
 use rstd::cmp::Ordering;
 use codec::{Encode, Decode};
 
-#[cfg(feature = "std")]
-use std::convert::{TryFrom, TryInto};
+#[cfg(feature = "full_crypto")]
+use core::convert::{TryFrom, TryInto};
 #[cfg(feature = "std")]
 use substrate_bip39::seed_from_entropy;
 #[cfg(feature = "std")]
 use bip39::{Mnemonic, Language, MnemonicType};
+#[cfg(feature = "full_crypto")]
+use crate::{hashing::blake2_256, crypto::{Pair as TraitPair, DeriveJunction, SecretStringError}};
 #[cfg(feature = "std")]
-use crate::{hashing::blake2_256, crypto::{Pair as TraitPair, DeriveJunction, SecretStringError, Ss58Codec}};
+use crate::crypto::Ss58Codec;
 #[cfg(feature = "std")]
 use serde::{de, Serializer, Serialize, Deserializer, Deserialize};
 use crate::crypto::{Public as TraitPublic, UncheckedFrom, CryptoType, Derive};
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 use secp256k1::{PublicKey, SecretKey};
 
 /// A secret seed (which is bytewise essentially equivalent to a SecretKey).
 ///
 /// We need it as a different type because `Seed` is expected to be AsRef<[u8]>.
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 type Seed = [u8; 32];
 
 /// The ECDSA 33-byte compressed public key.
@@ -72,7 +76,7 @@ impl Default for Public {
 }
 
 /// A key pair.
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 #[derive(Clone)]
 pub struct Pair {
 	public: PublicKey,
@@ -117,7 +121,7 @@ impl From<Public> for [u8; 33] {
 	}
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 impl From<Pair> for Public {
 	fn from(x: Pair) -> Self {
 		x.public()
@@ -160,9 +164,9 @@ impl<'de> Deserialize<'de> for Public {
 	}
 }
 
-#[cfg(feature = "std")]
-impl std::hash::Hash for Public {
-	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+#[cfg(feature = "full_crypto")]
+impl rstd::hash::Hash for Public {
+	fn hash<H: rstd::hash::Hasher>(&self, state: &mut H) {
 		self.0.hash(state);
 	}
 }
@@ -238,10 +242,10 @@ impl std::fmt::Debug for Signature {
 	}
 }
 
-#[cfg(feature = "std")]
-impl std::hash::Hash for Signature {
-	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-		std::hash::Hash::hash(&self.0[..], state);
+#[cfg(feature = "full_crypto")]
+impl rstd::hash::Hash for Signature {
+	fn hash<H: rstd::hash::Hasher>(&self, state: &mut H) {
+		rstd::hash::Hash::hash(&self.0[..], state);
 	}
 }
 
@@ -255,7 +259,7 @@ impl Signature {
 	}
 
 	/// Recover the public key from this signature and a message.
-	#[cfg(feature = "std")]
+	#[cfg(feature = "full_crypto")]
 	pub fn recover<M: AsRef<[u8]>>(&self, message: M) -> Option<Public> {
 		let message = secp256k1::Message::parse(&blake2_256(message.as_ref()));
 		let sig: (_, _) = self.try_into().ok()?;
@@ -264,7 +268,7 @@ impl Signature {
 	}
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 impl From<(secp256k1::Signature, secp256k1::RecoveryId)> for Signature {
 	fn from(x: (secp256k1::Signature, secp256k1::RecoveryId)) -> Signature {
 		let mut r = Self::default();
@@ -274,7 +278,7 @@ impl From<(secp256k1::Signature, secp256k1::RecoveryId)> for Signature {
 	}
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 impl<'a> TryFrom<&'a Signature> for (secp256k1::Signature, secp256k1::RecoveryId) {
 	type Error = ();
 	fn try_from(x: &'a Signature) -> Result<(secp256k1::Signature, secp256k1::RecoveryId), Self::Error> {
@@ -329,7 +333,7 @@ impl TraitPublic for Public {
 impl Derive for Public {}
 
 /// Derive a single hard junction.
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 fn derive_hard_junction(secret_seed: &Seed, cc: &[u8; 32]) -> Seed {
 	("Secp256k1HDKD", secret_seed, cc).using_encoded(|data| {
 		let mut res = [0u8; 32];
@@ -339,13 +343,13 @@ fn derive_hard_junction(secret_seed: &Seed, cc: &[u8; 32]) -> Seed {
 }
 
 /// An error when deriving a key.
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 pub enum DeriveError {
 	/// A soft key was found in the path (and is unsupported).
 	SoftKeyInPath,
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 impl TraitPair for Pair {
 	type Public = Public;
 	type Seed = Seed;
@@ -355,6 +359,7 @@ impl TraitPair for Pair {
 	/// Generate new secure (random) key pair and provide the recovery phrase.
 	///
 	/// You can recover the same key later with `from_phrase`.
+	#[cfg(feature = "std")]
 	fn generate_with_phrase(password: Option<&str>) -> (Pair, String, Seed) {
 		let mnemonic = Mnemonic::new(MnemonicType::Words12, Language::English);
 		let phrase = mnemonic.phrase();
@@ -368,6 +373,7 @@ impl TraitPair for Pair {
 	}
 
 	/// Generate key pair from given recovery phrase and password.
+	#[cfg(feature = "std")]
 	fn from_phrase(phrase: &str, password: Option<&str>) -> Result<(Pair, Seed), SecretStringError> {
 		let big_seed = seed_from_entropy(
 			Mnemonic::from_phrase(phrase, Language::English)
@@ -454,7 +460,7 @@ impl TraitPair for Pair {
 	}
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature = "full_crypto")]
 impl Pair {
 	/// Get the seed for this key.
 	pub fn seed(&self) -> Seed {
@@ -463,6 +469,7 @@ impl Pair {
 
 	/// Exactly as `from_string` except that if no matches are found then, the the first 32
 	/// characters are taken (padded with spaces as necessary) and used as the MiniSecretKey.
+	#[cfg(feature = "std")]
 	pub fn from_legacy_string(s: &str, password_override: Option<&str>) -> Pair {
 		Self::from_string(s, password_override).unwrap_or_else(|_| {
 			let mut padded_seed: Seed = [' ' as u8; 32];
@@ -474,16 +481,16 @@ impl Pair {
 }
 
 impl CryptoType for Public {
-	#[cfg(feature="std")]
+	#[cfg(feature="full_crypto")]
 	type Pair = Pair;
 }
 
 impl CryptoType for Signature {
-	#[cfg(feature="std")]
+	#[cfg(feature="full_crypto")]
 	type Pair = Pair;
 }
 
-#[cfg(feature = "std")]
+#[cfg(feature="full_crypto")]
 impl CryptoType for Pair {
 	type Pair = Pair;
 }
diff --git a/core/primitives/src/ed25519.rs b/core/primitives/src/ed25519.rs
index cecb87cd5a76b..0a25b8c806644 100644
--- a/core/primitives/src/ed25519.rs
+++ b/core/primitives/src/ed25519.rs
@@ -30,7 +30,9 @@ use substrate_bip39::seed_from_entropy;
 #[cfg(feature = "std")]
 use bip39::{Mnemonic, Language, MnemonicType};
 #[cfg(feature = "full_crypto")]
-use crate::crypto::{Pair as TraitPair, DeriveJunction, SecretStringError, Ss58Codec};
+use crate::crypto::{Pair as TraitPair, DeriveJunction, SecretStringError};
+#[cfg(feature = "std")]
+use crate::crypto::Ss58Codec;
 #[cfg(feature = "std")]
 use serde::{de, Serializer, Serialize, Deserializer, Deserialize};
 use crate::{crypto::{Public as TraitPublic, UncheckedFrom, CryptoType, Derive}};
@@ -42,7 +44,7 @@ use crate::{crypto::{Public as TraitPublic, UncheckedFrom, CryptoType, Derive}};
 type Seed = [u8; 32];
 
 /// A public key.
-#[cfg_attr(feature = "std", derive(Hash))]
+#[cfg_attr(feature = "full_crypto", derive(Hash))]
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Encode, Decode, Default)]
 pub struct Public(pub [u8; 32]);
 
diff --git a/core/primitives/src/sr25519.rs b/core/primitives/src/sr25519.rs
index 5838aa380b601..7bec910d730ca 100644
--- a/core/primitives/src/sr25519.rs
+++ b/core/primitives/src/sr25519.rs
@@ -31,8 +31,11 @@ use substrate_bip39::mini_secret_from_entropy;
 use bip39::{Mnemonic, Language, MnemonicType};
 #[cfg(feature = "full_crypto")]
 use crate::crypto::{
-	Pair as TraitPair, DeriveJunction, Infallible, SecretStringError, Ss58Codec
+	Pair as TraitPair, DeriveJunction, Infallible, SecretStringError
 };
+#[cfg(feature = "std")]
+use crate::crypto::Ss58Codec;
+
 use crate::{crypto::{Public as TraitPublic, UncheckedFrom, CryptoType, Derive}};
 use crate::hash::{H256, H512};
 use codec::{Encode, Decode};
@@ -47,7 +50,7 @@ use schnorrkel::keys::{MINI_SECRET_KEY_LENGTH, SECRET_KEY_LENGTH};
 const SIGNING_CTX: &[u8] = b"substrate";
 
 /// An Schnorrkel/Ristretto x25519 ("sr25519") public key.
-#[cfg_attr(feature = "std", derive(Hash))]
+#[cfg_attr(feature = "full_crypto", derive(Hash))]
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Encode, Decode, Default)]
 pub struct Public(pub [u8; 32]);
 
@@ -440,7 +443,7 @@ impl TraitPair for Pair {
 			_ => Err(SecretStringError::InvalidSeedLength)
 		}
 	}
-
+	#[cfg(feature = "std")]
 	fn generate_with_phrase(password: Option<&str>) -> (Pair, String, Seed) {
 		let mnemonic = Mnemonic::new(MnemonicType::Words12, Language::English);
 		let phrase = mnemonic.phrase();