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aes.c
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aes.c
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/*
* Copyright © 2022 - polfosol
* μAES ™ is a minimalist all-in-one library for AES encryption
*/
/*
* You can use different AES algorithms by changing this macro.
* Default is AES-128
*/
#define AES___ 128 /* or 256 (or 192; not standardized in some modes) */
/*
* AES block-cipher modes of operation. The following modes can be enabled /
* disabled by setting their corresponding macros to TRUE (1) or FALSE (0).
*/
#define BLOCKCIPHERS 1
#define AEAD_MODES 1 /* authenticated encryption with associated data. */
#if BLOCKCIPHERS
#define ECB 1 /* electronic code-book (NIST SP 800-38A) */
#define CBC 1 /* cipher block chaining (NIST SP 800-38A) */
#define CFB 1 /* cipher feedback (NIST SP 800-38A) */
#define OFB 1 /* output feedback (NIST SP 800-38A) */
#define CTR 1 /* counter-block (NIST SP 800-38A) */
#define XEX 1 /* xor-encrypt-xor (NIST SP 800-38E) */
#define KWA 1 /* key wrap with authentication (NIST SP 800-38F) */
#define FPE 1 /* format-preserving encryption (NIST SP 800-38G) */
#endif
#if AEAD_MODES
#define CMAC 1 /* message authentication code (NIST SP 800-38B) */
#if CTR
#define CCM 1 /* counter with CBC-MAC (RFC-3610/NIST SP 800-38C) */
#define GCM 1 /* Galois/counter mode with GMAC (NIST SP 800-38D) */
#define EAX 1 /* encrypt-authenticate-translate (ANSI C12.22) */
#define SIV 1 /* synthetic initialization vector (RFC-5297) */
#define GCM_SIV 1 /* nonce misuse-resistant AES-GCM (RFC-8452) */
#endif
#if XEX
#define OCB 1 /* offset codebook mode with PMAC (RFC-7253) */
#endif
#define POLY1305 1 /* poly1305-AES mac (https://cr.yp.to/mac.html) */
#endif
#if CBC
#define CTS 1 /* ciphertext stealing (CS3: unconditional swap) */
#endif
#if XEX
#define XTS 1 /* XEX tweaked-codebook with ciphertext stealing */
#endif
#if CTR
#define CTR_NA 1 /* pure counter mode, with no authentication */
#endif
#if EAX
#define EAXP 1 /* EAX-prime, as specified by IEEE Std 1703 */
#endif
#define WTF !(AEAD_MODES || BLOCKCIPHERS)
#define M_RIJNDAEL WTF /* none of above; just rijndael API. dude.., why? */
/**----------------------------------------------------------------------------
Refer to the BOTTOM OF THIS DOCUMENT for some explanations about these macros:
-----------------------------------------------------------------------------*/
#if ECB || (CBC && !CTS) || (XEX && !XTS)
#define AES_PADDING 0 /* standard values: (1) PKCS#7 (2) ISO/IEC7816-4 */
#endif
#if ECB || CBC || XEX || KWA || M_RIJNDAEL
#define DECRYPTION 1 /* rijndael decryption is NOT required otherwise. */
#endif
#if FPE
#define CUSTOM_ALPHABET \
0 /* if disabled, use default alphabet (digits 0..9) \
*/
#define FF_X 1 /* algorithm type: (1) for FF1, or (3) for FF3-1 */
#endif
#if CTR_NA
#define CTR_IV_LENGTH 12 /* for using the last 32 bits as counter */
#define CTR_STARTVALUE 1 /* recommended value according to the RFC-3686. */
#endif
#if CCM
#define CCM_NONCE_LEN 11 /* for 32-bit count (since one byte is reserved). */
#define CCM_TAG_LEN 16 /* must be an even number in the range of 4..16 */
#endif
#if GCM
#define GCM_NONCE_LEN 12 /* RECOMMENDED. but other values are supported. */
#endif
#if EAX && !EAXP
#define EAX_NONCE_LEN 16 /* no specified limit; can be arbitrarily large. */
#endif
#if OCB
#define OCB_NONCE_LEN 12 /* RECOMMENDED. must be positive and less than 16. */
#define OCB_TAG_LEN 16 /* again, please see the bottom of this document! */
#endif
/**----------------------------------------------------------------------------
Since <stdint.h> is not a part of ANSI-C, we may need a 'trick' to use uint8_t
-----------------------------------------------------------------------------*/
#include <string.h>
#if __STDC_VERSION__ > 199900L || __cplusplus > 201100L || defined(_MSC_VER)
#include <stdint.h>
#else
#include <limits.h>
#if CHAR_BIT == 8
typedef unsigned char uint8_t;
#endif
#if INT_MAX > 200000L
typedef int int32_t;
#else
typedef long int32_t;
#endif
#endif
/**----------------------------------------------------------------------------
Encryption/decryption of a single block with Rijndael
-----------------------------------------------------------------------------*/
#if M_RIJNDAEL
void AES_Cipher(const uint8_t *key, /* encryption/decryption key */
const char mode, /* encrypt: 'E', decrypt: 'D' */
const uint8_t x[16], /* input bytes (or input block) */
uint8_t y[16]); /* output block */
#endif
/**----------------------------------------------------------------------------
Main functions for ECB-AES block ciphering
-----------------------------------------------------------------------------*/
#if ECB
void AES_ECB_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
char AES_ECB_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* ECB */
/**----------------------------------------------------------------------------
Main functions for CBC-AES block ciphering
-----------------------------------------------------------------------------*/
#if CBC
char AES_CBC_encrypt(const uint8_t *key, /* encryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
char AES_CBC_decrypt(const uint8_t *key, /* decryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* CBC */
/**----------------------------------------------------------------------------
Main functions for CFB-AES block ciphering
-----------------------------------------------------------------------------*/
#if CFB
void AES_CFB_encrypt(const uint8_t *key, /* encryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
void AES_CFB_decrypt(const uint8_t *key, /* decryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* CFB */
/**----------------------------------------------------------------------------
Main functions for OFB-AES block ciphering
-----------------------------------------------------------------------------*/
#if OFB
void AES_OFB_encrypt(const uint8_t *key, /* encryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
void AES_OFB_decrypt(const uint8_t *key, /* decryption key */
const uint8_t iVec[16], /* initialization vector */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* OFB */
/**----------------------------------------------------------------------------
Main functions for XTS-AES block ciphering
-----------------------------------------------------------------------------*/
#if XTS
char AES_XTS_encrypt(const uint8_t *keys, /* encryption key pair */
const uint8_t *tweak, /* tweak value (unit/sector ID) */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
char AES_XTS_decrypt(const uint8_t *keys, /* decryption key pair */
const uint8_t *tweak, /* tweak value (unit/sector ID) */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* XTS */
/**----------------------------------------------------------------------------
Main functions for CTR-AES block ciphering
-----------------------------------------------------------------------------*/
#if CTR_NA
void AES_CTR_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *iv, /* initialization vector/ nonce */
const uint8_t *pntxt, /* plaintext buffer */
const size_t ptextLen, /* length of input plain text */
uint8_t *crtxt); /* cipher-text result */
void AES_CTR_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *iv, /* initialization vector/ nonce */
const uint8_t *crtxt, /* cipher-text buffer */
const size_t crtxtLen, /* length of input cipher text */
uint8_t *pntxt); /* plaintext result */
#endif /* CTR */
/**----------------------------------------------------------------------------
Main functions for SIV-AES block ciphering
-----------------------------------------------------------------------------*/
#if SIV
void AES_SIV_encrypt(const uint8_t *keys, /* encryption key pair */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t iv[16], /* synthesized initial-vector */
uint8_t *crtxt); /* cipher-text result */
char AES_SIV_decrypt(const uint8_t *keys, /* decryption key pair */
const uint8_t iv[16], /* provided initial-vector */
const uint8_t *crtxt, /* cipher text */
const size_t crtxtLen, /* length of input cipher-text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *pntxt); /* plain-text result */
#endif /* SIV */
/**----------------------------------------------------------------------------
Main functions for GCM-AES block ciphering
-----------------------------------------------------------------------------*/
#if GCM
void AES_GCM_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *crtxt, /* cipher-text result */
uint8_t auTag[16]); /* message authentication tag */
char AES_GCM_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *crtxt, /* cipher text + appended tag */
const size_t crtxtLen, /* length of input cipher-text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
const uint8_t tagLen, /* size of tag (if any) */
uint8_t *pntxt); /* plain-text result */
#endif /* GCM */
/**----------------------------------------------------------------------------
Main functions for CCM-AES block ciphering
-----------------------------------------------------------------------------*/
#if CCM
void AES_CCM_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *crtxt, /* cipher-text result */
uint8_t auTag[16]); /* message authentication tag */
char AES_CCM_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *crtxt, /* cipher text + appended tag */
const size_t crtxtLen, /* length of input cipher-text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
const uint8_t tagLen, /* size of tag (if any) */
uint8_t *pntxt); /* plain-text result */
#endif /* CCM */
/**----------------------------------------------------------------------------
Main functions for OCB-AES block ciphering
-----------------------------------------------------------------------------*/
#if OCB
void AES_OCB_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *crtxt, /* cipher-text result */
uint8_t auTag[16]); /* message authentication tag */
char AES_OCB_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *nonce, /* a.k.a initialization vector */
const uint8_t *crtxt, /* cipher text + appended tag */
const size_t crtxtLen, /* length of input cipher-text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
const uint8_t tagLen, /* size of tag (if any) */
uint8_t *pntxt); /* plain-text result */
#endif /* OCB */
/**----------------------------------------------------------------------------
Main functions for EAX-AES mode; more info at the bottom of this document.
-----------------------------------------------------------------------------*/
#if EAX
void AES_EAX_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *nonce, /* arbitrary-size nonce array */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
#if EAXP
const size_t nonceLen, /* size of provided nonce */
uint8_t *crtxt); /* cipher-text result + mac (4) */
#else
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *crtxt, /* cipher-text result */
uint8_t auTag[16]); /* message authentication tag */
#endif
char AES_EAX_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *nonce, /* arbitrary-size nonce array */
const uint8_t *crtxt, /* cipher text + appended tag */
const size_t crtxtLen, /* length of input cipher-text */
#if EAXP
const size_t nonceLen, /* size of provided nonce */
#else
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
const uint8_t tagLen, /* size of tag (if any) */
#endif
uint8_t *pntxt); /* plain-text result */
#endif /* EAX */
/**----------------------------------------------------------------------------
Main functions for GCM-SIV-AES block ciphering
-----------------------------------------------------------------------------*/
#if GCM_SIV
void GCM_SIV_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *nonce, /* provided 96-bit nonce */
const uint8_t *pntxt, /* plain text */
const size_t ptextLen, /* length of input plain text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
uint8_t *crtxt, /* cipher-text result */
uint8_t auTag[16]); /* 16-bytes mandatory tag */
char GCM_SIV_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *nonce, /* provided 96-bit nonce */
const uint8_t *crtxt, /* cipher text + appended tag */
const size_t crtxtLen, /* length of input cipher-text */
const uint8_t *aData, /* added authentication data */
const size_t aDataLen, /* size of authentication data */
const uint8_t tagLen, /* size of tag (must be 16) */
uint8_t *pntxt); /* plain-text result */
#endif /* GCM-SIV */
/**----------------------------------------------------------------------------
Main functions for AES key-wrapping
-----------------------------------------------------------------------------*/
#if KWA
char AES_KEY_wrap(const uint8_t *kek, /* key encryption key */
const uint8_t *secret, /* input secret to be wrapped */
const size_t secretLen, /* size of input */
uint8_t *wrapped); /* key-wrapped output */
char AES_KEY_unwrap(const uint8_t *kek, /* key encryption key */
const uint8_t *wrapped, /* key-wrapped secret */
const size_t wrapLen, /* size of input (secretLen +8) */
uint8_t *secret); /* buffer for unwrapped key */
#endif /* KWA */
/**----------------------------------------------------------------------------
Main functions for FPE-AES; more info at the bottom of this page.
-----------------------------------------------------------------------------*/
#if FPE
char AES_FPE_encrypt(const uint8_t *key, /* encryption key */
const uint8_t *tweak, /* tweak bytes */
#if FF_X == 3
#define FF3_TWEAK_LEN 7 /* set 7 for FF3-1, or 8 if FF3 */
#else
const size_t tweakLen, /* size of tweak array */
#endif
const void *pntxt, /* input plaintext string */
const size_t ptextLen, /* length of plaintext string */
void *crtxt); /* cipher-text result */
char AES_FPE_decrypt(const uint8_t *key, /* decryption key */
const uint8_t *tweak, /* tweak bytes */
#if FF_X != 3
const size_t tweakLen, /* size of tweak array */
#endif
const void *crtxt, /* input ciphertext string */
const size_t crtxtLen, /* length of ciphertext string */
void *pntxt); /* plain-text result */
#endif /* FPE */
/**----------------------------------------------------------------------------
Main function for Poly1305-AES message authentication code
-----------------------------------------------------------------------------*/
#if POLY1305
void AES_Poly1305(const uint8_t *keys, /* encryption/mixing key pair */
const uint8_t nonce[16], /* the 128-bit nonce */
const void *data, /* input data buffer */
const size_t dataSize, /* size of data in bytes */
uint8_t mac[16]); /* poly1305-AES mac of data */
#endif
/**----------------------------------------------------------------------------
Main function for AES Cipher-based Message Authentication Code
-----------------------------------------------------------------------------*/
#if CMAC
void AES_CMAC(const uint8_t *key, /* encryption/cipher key */
const void *data, /* input data buffer */
const size_t dataSize, /* size of data in bytes */
uint8_t mac[16]); /* CMAC result of input data */
#endif
/**----------------------------------------------------------------------------
The error codes and key length should be defined here for external references:
-----------------------------------------------------------------------------*/
#define ENCRYPTION_FAILURE 0x1E
#define DECRYPTION_FAILURE 0x1D
#define AUTHENTICATION_FAILURE 0x1A
#define ENDED_IN_SUCCESS 0x00
#if (AES___ != 256) && (AES___ != 192)
#define AES_KEY_SIZE 16
#else
#define AES_KEY_SIZE (AES___ / 8)
#endif
/******************************************************************************\
¦ Notes and remarks about the above-defined macros ¦
--------------------------------------------------------------------------------
* In EBC/CBC/XEX modes, the size of input must be a multiple of block-size.
Otherwise it needs to be padded. The simplest (default) padding mode is to
fill the rest of block by zeros. Supported standard padding methods are
PKCS#7 and ISO/IEC 7816-4, which can be enabled by the AES_PADDING macro.
* In many texts, you may see that the words 'nonce' and 'initialization vector'
are used interchangeably. But they have a subtle difference. Sometimes nonce
is a part of the I.V, which itself can either be a full block or a partial
one. In CBC/CFB/OFB modes, the provided I.V must be a full block. In pure
CTR mode (CTR_NA) you can either provide a 96-bit I.V and let the count
start at CTR_STARTVALUE, or use a full block IV.
* In AEAD modes, the size of nonce and tag might be a parameter of the algorithm
such that changing them affect the results. The GCM/EAX modes support
arbitrary sizes for nonce. In CCM, the nonce length may vary from 8 to 13
bytes. Also the tag size is an EVEN number between 4..16. In OCB, the nonce
size is 1..15 and the tag is 0..16 bytes. Note that the 'calculated' tag-
size is always 16 bytes which can later be truncated to desired values. So
in encryption functions, the provided authTag buffer must be 16 bytes long.
* For the EAX mode of operation, the IEEE-1703 standard defines EAX' which is a
modified version that combines AAD and nonce. Also the tag size is fixed to
4 bytes. So EAX-prime functions don't need to take additional authentication
data and tag-size as separate parameters.
* In SIV mode, multiple separate units of authentication headers can be provided
for the nonce synthesis. Here we assume that only one unit of AAD (aData) is
sufficient, which is practically true.
* The FPE mode has two distinct NIST-approved algorithms, namely FF1 and FF3-1.
Use the FF_X macro to change the encryption method, which is FF1 by default.
The input and output strings must be consisted of a fixed set of characters
called 'the alphabet'. The default alphabet is the set of digits {'0'..'9'}.
If you want to use a different alphabet, set the CUSTOM_ALPHABET macro and
refer to the "micro_fpe.h" header. This file is needed only when a custom
alphabet has to be defined, and contains some illustrative examples and
clear guidelines on how to do so.
* The key wrapping mode is also denoted by KW. In this mode, the input secret is
divided into 64bit blocks. Number of blocks is at least 2, and it is assumed
that no padding is required. For padding, the KWP mode must be used which is
easily implementable, but left as an exercise! In the NIST document you may
find some mentions of TKW which is for 3DES and irrelevant here. Anyway, the
wrapped output has an additional block, i.e. wrappedSize = secretSize + 8.
* Let me explain three extra options that are defined in the source file. If the
length of the input cipher/plain text is 'always' less than 4KB, you can
enable the SMALL_CIPHER macro to save a few bytes in the compiled code. This
assumption is likely to be valid for some embedded systems and small-scale
applications. Furthermore, disabling that other macro, DONT_USE_FUNCTIONS
had a considerable effect on the size of the compiled code in my own tests.
Nonetheless, others might get a different result from them.
The INCREASE_SECURITY macro, as its name suggests, is dealing with security
considerations. For example, since the RoundKey is declared as static array
it might get exposed to some attacks. By enabling this macro, round-keys are
wiped out at the end of ciphering operations. However, please keep in mind
that this is NOT A GUARANTEE against side-channel attacks.
*/
/*----------------------------------------------------------------------------*\
Global constants, data types, and important / useful MACROs
\*----------------------------------------------------------------------------*/
#define KEYSIZE AES_KEY_SIZE
#define BLOCKSIZE (128 / 8) /* Block length in AES is 'always' 128-bits. */
#define Nb (BLOCKSIZE / 4) /* The number of columns comprising a AES state */
#define Nk (KEYSIZE / 4) /* The number of 32 bit words in a key. */
#define ROUNDS (Nk + 6) /* The number of rounds in AES Cipher. */
#define IMPLEMENT(x) (x) > 0
#define INCREASE_SECURITY 0
#define DONT_USE_FUNCTIONS 0
#define SMALL_CIPHER 0 /* for more info, see the bottom of header file */
/** block_t indicates fixed-size memory blocks, and state_t represents the state
* matrix. note that state[i][j] means the i-th COLUMN and j-th ROW of matrix */
typedef uint8_t block_t[BLOCKSIZE];
typedef uint8_t state_t[Nb][4];
/*----------------------------------------------------------------------------*\
Private variables:
\*----------------------------------------------------------------------------*/
/** The array that stores all round keys during the AES key-expansion process */
static uint8_t RoundKey[BLOCKSIZE * ROUNDS + KEYSIZE];
/** Lookup-tables are static constant, so that they can be placed in read-only
* storage instead of RAM. They can be computed dynamically trading ROM for RAM.
* This may be useful in (embedded) bootloader applications, where ROM is often
* limited. Note that sbox[y] = x, if and only if rsbox[x] = y. You may read the
* wikipedia article for more info: https://en.wikipedia.org/wiki/Rijndael_S-box
*/
static const char sbox[256] =
"c|w{\362ko\3050\1g+\376\327\253\x76\312\202\311}\372YG\360\255\324\242\257"
"\234\244r\300\267\375\223&6\?\367\3144\245\345\361q\3301\25\4\307#\303\030"
"\226\5\232\a\22\200\342\353\'\262u\t\203,\32\33nZ\240R;\326\263)\343/\204S"
"\321\0\355 \374\261[j\313\2769JLX\317\320\357\252\373CM3\205E\371\02\177P<"
"\237\250Q\243@\217\222\2358\365\274\266\332!\20\377\363\322\315\f\023\354_"
"\227D\27\304\247~=d]\31s`\201O\334\"*\220\210F\356\270\24\336^\v\333\3402:"
"\nI\06$\\\302\323\254b\221\225\344y\347\3107m\215\325N\251lV\364\352ez\256"
"\b\272x%.\034\246\264\306\350\335t\37K\275\213\212p>\265fH\3\366\16a5W\271"
"\206\301\035\236\341\370\230\21i\331\216\224\233\036\207\351\316U(\337\214"
"\241\211\r\277\346BhA\231-\17\260T\273\26";
#if DECRYPTION
static const char rsbox[256] =
"R\tj\32506\2458\277@\243\236\201\363\327\373|\3439\202\233/\377\2074\216CD"
"\304\336\351\313T{\2242\246\302#=\356L\225\vB\372\303N\b.\241f(\331$\262v["
"\242Im\213\321%r\370\366d\206h\230\026\324\244\\\314]e\266\222lpHP\375\355"
"\271\332^\25FW\247\215\235\204\220\330\253\0\214\274\323\n\367\344X\05\270"
"\263E\6\320,\036\217\312?\17\2\301\257\275\3\1\023\212k:\221\21AOg\334\352"
"\227\362\317\316\360\264\346s\226\254t\"\347\2555\205\342\3717\350\34u\337"
"nG\361\32q\35)\305\211o\267b\16\252\30\276\33\374V>K\306\322y \232\333\300"
"\376x\315Z\364\037\335\2503\210\a\3071\261\22\20Y\'\200\354_`Q\177\251\031"
"\265J\r-\345z\237\223\311\234\357\240\340;M\256*\365\260\310\353\273<\203S"
"\231a\27+\4~\272w\326&\341i\24cU!\f}";
#endif
/*----------------------------------------------------------------------------*\
Auxiliary functions for the Rijndael algorithm
\*----------------------------------------------------------------------------*/
#define SBoxValue(x) (sbox[x])
#define InvSBoxValue(x) (rsbox[x]) /* omitted dynamic s-box calculation */
#define COPY32BIT(x, y) *(int32_t *) &(y) = *(int32_t *) &x
#define XOR32BITS(x, y) *(int32_t *) &(y) ^= *(int32_t *) &x
#if DONT_USE_FUNCTIONS
/** note: 'long long' type is NOT supported in C89. so this may throw errors: */
#define xorBlock(x, y) \
{ \
*(long long *) &(y)[0] ^= *(long long const *) &(x)[0]; \
*(long long *) &(y)[8] ^= *(long long const *) &(x)[8]; \
}
#define xtime(x) (x & 0x80 ? x << 1 ^ 0x11b : x * 2)
#define gmul(x, y) \
(x * (y <= 13)) ^ (xtime(x) * (y / 2 & 1)) ^ \
(xtime(xtime(x)) * (y >= 13)) ^ (xtime(xtime(xtime(x))))
#else
/** XOR two 128bit numbers (blocks) called src and dest, so that: dest ^= src */
static void xorBlock(const block_t src, block_t dest)
{
uint8_t i;
for (i = 0; i < BLOCKSIZE; ++i) /* many CPUs have single instruction */
{ /* such as XORPS for 128-bit-xor. */
dest[i] ^= src[i]; /* see the file: x86-improvements */
}
}
/** doubling in GF(2^8): left-shift and if carry bit is set, xor it with 0x1b */
static uint8_t xtime(uint8_t x)
{
return (x > 0x7f) * 0x1b ^ (x << 1);
}
#if DECRYPTION
/** This function multiplies two numbers in the Galois bit field of GF(2^8).. */
static uint8_t gmul(uint8_t x, uint8_t y)
{
uint8_t m;
for (m = 0; y > 1; y >>= 1) /* optimized algorithm for nonzero y */
{
if (y & 01)
m ^= x;
x = xtime(x);
}
return m ^ x; /* or use (9 11 13 14) lookup tables */
}
#endif
#endif
/*----------------------------------------------------------------------------*\
Main functions for the Rijndael encryption algorithm
\*----------------------------------------------------------------------------*/
/** This function produces (ROUNDS+1) round keys, which are used in each round
* to encrypt/decrypt the intermediate states. First round key is the main key
* itself, and other rounds are constructed from the previous ones as follows */
static void KeyExpansion(const uint8_t *key)
{
uint8_t rcon = 1, i;
memcpy(RoundKey, key, KEYSIZE);
for (i = KEYSIZE; i < (ROUNDS + 1) * Nb * 4; i += 4) {
switch (i % KEYSIZE) {
case 0:
memcpy(&RoundKey[i], &RoundKey[i - KEYSIZE], KEYSIZE);
#if Nk == 4
if (!rcon)
rcon = 0x1b; /* RCON may reach 0 only in AES-128. */
#endif
RoundKey[i] ^= SBoxValue(RoundKey[i - 3]) ^ rcon;
RoundKey[i + 1] ^= SBoxValue(RoundKey[i - 2]);
RoundKey[i + 2] ^= SBoxValue(RoundKey[i - 1]);
RoundKey[i + 3] ^= SBoxValue(RoundKey[i - 4]);
rcon <<= 1;
break;
#if Nk == 8 /* additional round only for AES-256 */
case 16:
RoundKey[i] ^= SBoxValue(RoundKey[i - 4]);
RoundKey[i + 1] ^= SBoxValue(RoundKey[i - 3]);
RoundKey[i + 2] ^= SBoxValue(RoundKey[i - 2]);
RoundKey[i + 3] ^= SBoxValue(RoundKey[i - 1]);
break;
#endif
default:
XOR32BITS(RoundKey[i - 0x4], RoundKey[i]);
break;
}
}
}
/** Add the round keys to the rijndael state matrix (adding in GF means XOR). */
static void AddRoundKey(const uint8_t round, block_t state)
{
xorBlock(RoundKey + BLOCKSIZE * round, state);
}
/** Substitute values in the state matrix with associated values in the S-box */
static void SubBytes(block_t state)
{
uint8_t i;
for (i = 0; i < BLOCKSIZE; ++i) {
state[i] = SBoxValue(state[i]);
}
}
/** Shift/rotate the rows of the state matrix to the left. Each row is shifted
* with a different offset (= Row number). So the first row is not shifted .. */
static void ShiftRows(state_t *state)
{
uint8_t temp = (*state)[0][1];
(*state)[0][1] = (*state)[1][1];
(*state)[1][1] = (*state)[2][1];
(*state)[2][1] = (*state)[3][1];
(*state)[3][1] = temp; /* Rotated the 1st row 1 columns to left */
temp = (*state)[0][2];
(*state)[0][2] = (*state)[2][2];
(*state)[2][2] = temp;
temp = (*state)[1][2];
(*state)[1][2] = (*state)[3][2];
(*state)[3][2] = temp; /* Rotated the 2nd row 2 columns to left */
temp = (*state)[0][3];
(*state)[0][3] = (*state)[3][3];
(*state)[3][3] = (*state)[2][3];
(*state)[2][3] = (*state)[1][3];
(*state)[1][3] = temp; /* Rotated the 3rd row 3 columns to left */
}
/** Mix the columns of the state matrix. See: crypto.stackexchange.com/q/2402 */
static void MixColumns(state_t *state)
{
uint8_t a, b, c, d, i;
for (i = 0; i < Nb; ++i) {
a = (*state)[i][0] ^ (*state)[i][1];
b = (*state)[i][1] ^ (*state)[i][2];
c = (*state)[i][2] ^ (*state)[i][3];
d = a ^ c; /* d is XOR of all elements in a column */
(*state)[i][0] ^= d ^ xtime(a);
(*state)[i][1] ^= d ^ xtime(b);
b ^= d; /* -> b = (*state)[i][3] ^ (*state)[i][0] */
(*state)[i][2] ^= d ^ xtime(c);
(*state)[i][3] ^= d ^ xtime(b);
}
}
/** Encrypt a plaintext input block and save the result/ciphertext as output. */
static void rijndaelEncrypt(const block_t input, block_t output)
{
uint8_t r;
state_t *state = (void *) output;
/* copy the input to the state matrix, and beware of undefined behavior.. */
if (input != output)
memcpy(state, input, BLOCKSIZE);
/* The encryption is carried out in #ROUNDS iterations, of which the first
* #ROUNDS-1 are identical. The last round doesn't involve mixing columns */
for (r = 0; r != ROUNDS;) {
AddRoundKey(r, output);
SubBytes(output);
ShiftRows(state);
++r != ROUNDS ? MixColumns(state) : AddRoundKey(ROUNDS, output);
}
}
/*----------------------------------------------------------------------------*\
Block-decryption part of the Rijndael algorithm
\*----------------------------------------------------------------------------*/
#if IMPLEMENT(DECRYPTION)
/** Substitutes the values in state matrix with values of the inverted S-box. */
static void InvSubBytes(block_t state)
{
uint8_t i;
for (i = 0; i < BLOCKSIZE; ++i) {
state[i] = InvSBoxValue(state[i]);
}
}
/** This function shifts/rotates the rows of the state matrix to the right .. */
static void InvShiftRows(state_t *state)
{
uint8_t temp = (*state)[3][1];
(*state)[3][1] = (*state)[2][1];
(*state)[2][1] = (*state)[1][1];
(*state)[1][1] = (*state)[0][1];
(*state)[0][1] = temp; /* Rotated first row 1 columns to right */
temp = (*state)[0][2];
(*state)[0][2] = (*state)[2][2];
(*state)[2][2] = temp;
temp = (*state)[1][2];
(*state)[1][2] = (*state)[3][2];
(*state)[3][2] = temp; /* Rotated second row 2 columns to right */
temp = (*state)[0][3];
(*state)[0][3] = (*state)[1][3];
(*state)[1][3] = (*state)[2][3];
(*state)[2][3] = (*state)[3][3];
(*state)[3][3] = temp; /* Rotated third row 3 columns to right */
}
/** Mixes the columns of (already-mixed) state matrix to reverse the process. */
static void InvMixColumns(state_t *state)
{
uint8_t i, x[4];
for (i = 0; i < Nb; ++i) /* see: crypto.stackexchange.com/q/2569 */
{
COPY32BIT((*state)[i][0], x[0]);
(*state)[i][0] =
gmul(x[0], 14) ^ gmul(x[1], 11) ^ gmul(x[2], 13) ^ gmul(x[3], 9);
(*state)[i][1] =
gmul(x[1], 14) ^ gmul(x[2], 11) ^ gmul(x[3], 13) ^ gmul(x[0], 9);
(*state)[i][2] =
gmul(x[2], 14) ^ gmul(x[3], 11) ^ gmul(x[0], 13) ^ gmul(x[1], 9);
(*state)[i][3] =
gmul(x[3], 14) ^ gmul(x[0], 11) ^ gmul(x[1], 13) ^ gmul(x[2], 9);
}
}
/** Decrypt a ciphertext input block and save the result/plaintext to output. */
static void rijndaelDecrypt(const block_t input, block_t output)
{
uint8_t r;
state_t *state = (void *) output;
/* copy the input into state matrix, i.e. state is initialized by input.. */
if (input != output)
memcpy(state, input, BLOCKSIZE);
/* Decryption completes after #ROUNDS iterations. All rounds except the 1st
* one are identical. The first round doesn't involve [inv]mixing columns */
for (r = ROUNDS; r != 0;) {
r-- != ROUNDS ? InvMixColumns(state) : AddRoundKey(ROUNDS, output);
InvShiftRows(state);
InvSubBytes(output);
AddRoundKey(r, output);
}
}
#endif /* DECRYPTION */
#if M_RIJNDAEL
/**
* @brief encrypt or decrypt a single block with a given key
* @param key a byte array with a fixed size of KEYSIZE
* @param mode mode of operation: 'E' (1) to encrypt, 'D' (0) to decrypt
* @param x input byte array with BLOCKSIZE bytes
* @param y output byte array with BLOCKSIZE bytes
*/
void AES_Cipher(const uint8_t *key, const char mode, const block_t x, block_t y)
{
KeyExpansion(key);
mode & 1 ? rijndaelEncrypt(x, y) : rijndaelDecrypt(x, y);
}
#endif
/*----------------------------------------------------------------------------*\
* Implementation of different block ciphers modes *
* Definitions & Auxiliary Functions *
\*----------------------------------------------------------------------------*/
#define AES_SetKey(key) KeyExpansion(key)
#if INCREASE_SECURITY
#define BURN(key) memset(key, 0, sizeof key)
#define SABOTAGE(buf, len) memset(buf, 0, len)
#define MISMATCH constmemcmp /* a.k.a secure memcmp */
#else
#define MISMATCH memcmp
#define SABOTAGE(buf, len) (void) buf
#define BURN(key) (void) key /* the line is ignored. */
#endif
#if INCREASE_SECURITY && AEAD_MODES
/** for constant-time comparison of memory blocks, to avoid "timing attacks". */
static uint8_t constmemcmp(const uint8_t *src, const uint8_t *dst, uint8_t n)
{
uint8_t cmp = 0;
while (n--) {
cmp |= src[n] ^ dst[n];
}
return cmp;
}
#endif
/** function-pointer types, indicating functions that take fixed-size blocks: */
typedef void (*fdouble_t)(block_t);
typedef void (*fmix_t)(const block_t, block_t);
#define LAST (BLOCKSIZE - 1) /* last index in a block */
#if SMALL_CIPHER
typedef uint8_t count_t;
#define incBlock(block, big) ++block[big ? LAST : 0]
#define xor2BVal(buf, num, pos) \
buf[pos - 1] ^= (num) >> 8; \
buf[pos] ^= num
#define copyLVal(buf, num, pos) \
buf[pos + 1] = (num) >> 8; \
buf[pos] = num
#else
typedef size_t count_t;
#if CTR || KWA || FPE
/** xor a byte array with a big-endian integer, whose LSB is at specified pos */
static void xor2BVal(uint8_t *buff, size_t val, uint8_t pos)
{
do
buff[pos--] ^= (uint8_t) val;
while (val >>= 8);
}
#endif
#if XTS || GCM_SIV
/** copy a little endian integer to the block, with LSB at specified position */
static void copyLVal(block_t block, size_t val, uint8_t pos)
{
do
block[pos++] = (uint8_t) val;
while (val >>= 8);
}
#endif
#if CTR
/** increment the value of a 128-bit counter block, regarding its endian-ness */
static void incBlock(block_t block, const char big)
{
uint8_t i = big ? LAST : 0;
if (i) /* big-endian counter */
{
while (!++block[i])
--i; /* (inc until no overflow) */
} else {
while (i < 4 && !++block[i])
++i;
}
}
#endif
#endif /* SMALL CIPHER */
#if EAX && !EAXP || SIV || OCB || CMAC
/** Multiply a block by two in Galois bit field GF(2^128): big-endian version */
static void doubleBGF128(block_t block)
{
int i, c = 0;
for (i = BLOCKSIZE; i; c >>= 8) /* from last byte (LSB) to */
{ /* first: left-shift, then */
c |= block[--i] << 1; /* append the previous MSBit */
block[i] = (uint8_t) c;
} /* if first MSBit is carried */
block[LAST] ^= c * 0x87; /* .. B ^= 10000111b (B.E.) */
}
#endif
#if XTS || EAXP
/** Multiply a block by two in the GF(2^128) field: the little-endian version */
static void doubleLGF128(block_t block)
{
int c = 0, i;
for (i = 0; i < BLOCKSIZE; c >>= 8) /* the same as doubleBGF128 */
{ /* ..but with reversed bytes */
c |= block[i] << 1;
block[i++] = (uint8_t) c;
}
block[0] ^= c * 0x87; /* B ^= 10000111b (L.E.) */
}
#endif
#if GCM
/** Divide a block by two in GF(2^128) field: used in big endian, 128bit mul. */
static void halveBGF128(block_t block)
{
unsigned i, c = 0;
for (i = 0; i < BLOCKSIZE; c <<= 8) /* from first to last byte, */
{ /* prepend the previous LSB */
c |= block[i]; /* then shift it to right. */
block[i++] = (uint8_t) (c >> 1);
} /* if block is odd (LSB = 1) */
if (c & 0x100)
block[0] ^= 0xe1; /* .. B ^= 11100001b << 120 */
}
/** This function carries out multiplication in 128bit Galois field GF(2^128) */
static void mulGF128(const block_t x, block_t y)
{
uint8_t i, j, result[BLOCKSIZE] = {0}; /* working memory */
for (i = 0; i < BLOCKSIZE; ++i) {
for (j = 0; j < 8; ++j) /* check all the bits of X, */
{
if (x[i] << j & 0x80) /* ..and if any bit is set, */
{
xorBlock(y, result); /* ..add Y to the result */
}