Here is a public domain implementation of AES written in C. This should compile in most standard compilers.
This is free and unencumbered software released into the public domain.
Aes.h
////////////////////////////////////////////////////////////////////////////////
// CryptLib_Aes
//
// Implementation of AES block cipher. Originally written by Kokke
// (https://github.com/kokke). Modified by WaterJuice retaining Public Domain
// license.
//
// AES is a block cipher that operates on 128 bit blocks. Encryption and
// Decryption routines use an AesContext which must be initialised with the key
// An AesContext can be initialised with a 128, 192, or 256 bit key. Use the
// AesInitialise[n] functions to initialise the context with the key. Once an
// AES context is initialised its contents are not changed by the encrypting
// and decrypting functions. A context only needs to be initialised once for
// any given key and the context may be used by the encrypt/decrypt functions
// in simultaneous threads. All operations are performed byte wise and this
// implementation works in both little and endian processors. There are no
// alignment requirements with the keys and data blocks.
//
// This is free and unencumbered software released into the public domain
// November 2017 waterjuice.org
////////////////////////////////////////////////////////////////////////////////
#pragma once
////////////////////////////////////////////////////////////////////////////////
// IMPORTS
////////////////////////////////////////////////////////////////////////////////
#include
////////////////////////////////////////////////////////////////////////////////
// TYPES
////////////////////////////////////////////////////////////////////////////////
#define AES_KEY_SIZE_128 16
#define AES_KEY_SIZE_192 24
#define AES_KEY_SIZE_256 32
#define AES_BLOCK_SIZE 16
// AesContext - This must be initialised using AesInitialise128,
// AesInitialise192 or AesInitialise256. Do not modify the contents of this
// structure directly.
typedef struct
{
uint32_t KeySizeInWords;
uint32_t NumberOfRounds;
uint8_t RoundKey[240];
} AesContext;
////////////////////////////////////////////////////////////////////////////////
// PUBLIC FUNCTIONS
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// AesInitialise128
//
// Initialises an AesContext with a 128 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise128
(
uint8_t const Key [AES_KEY_SIZE_128], // [in]
AesContext* Context // [out]
);
////////////////////////////////////////////////////////////////////////////////
// AesInitialise192
//
// Initialises an AesContext with a 192 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise192
(
uint8_t const Key [AES_KEY_SIZE_192], // [in]
AesContext* Context // [out]
);
////////////////////////////////////////////////////////////////////////////////
// AesInitialise256
//
// Initialises an AesContext with a 256 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise256
(
uint8_t const Key [AES_KEY_SIZE_256], // [in]
AesContext* Context // [out]
);
////////////////////////////////////////////////////////////////////////////////
// AesEncrypt
//
// Performs an AES encryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. Input and Output can
// point to same memory location, however it is more efficient to use
// AesEncryptInPlace in this situation.
////////////////////////////////////////////////////////////////////////////////
void
AesEncrypt
(
AesContext const* Context, // [in]
uint8_t const Input [AES_BLOCK_SIZE], // [in]
uint8_t Output [AES_BLOCK_SIZE] // [out]
);
////////////////////////////////////////////////////////////////////////////////
// AesDecrypt
//
// Performs an AES decryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. Input and Output can
// point to same memory location, however it is more efficient to use
// AesDecryptInPlace in this situation.
////////////////////////////////////////////////////////////////////////////////
void
AesDecrypt
(
AesContext const* Context, // [in]
uint8_t const Input [AES_BLOCK_SIZE], // [in]
uint8_t Output [AES_BLOCK_SIZE] // [out]
);
////////////////////////////////////////////////////////////////////////////////
// AesEncryptInPlace
//
// Performs an AES encryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. The encryption is
// performed in place.
////////////////////////////////////////////////////////////////////////////////
void
AesEncryptInPlace
(
AesContext const* Context, // [in]
uint8_t Block [AES_BLOCK_SIZE] // [in out]
);
////////////////////////////////////////////////////////////////////////////////
// AesDecryptInPlace
//
// Performs an AES decryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. The decryption is
// performed in place.
////////////////////////////////////////////////////////////////////////////////
void
AesDecryptInPlace
(
AesContext const* Context, // [in]
uint8_t Block [AES_BLOCK_SIZE] // [in out]
);
Aes.c
////////////////////////////////////////////////////////////////////////////////
// CryptLib_Aes
//
// Implementation of AES block cipher. Originally written by Kokke
// (https://github.com/kokke). Modified by WaterJuice retaining Public Domain
// license.
//
// This is free and unencumbered software released into the public domain
// November 2017 waterjuice.org
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// IMPORTS
////////////////////////////////////////////////////////////////////////////////
#include "CryptLib_Aes.h"
#include
#include
////////////////////////////////////////////////////////////////////////////////
// DEFINES
////////////////////////////////////////////////////////////////////////////////
// Array holding the intermediate results during decryption.
typedef struct
{
uint8_t state[4][4];
} AesState;
////////////////////////////////////////////////////////////////////////////////
// CONSTANTS
////////////////////////////////////////////////////////////////////////////////
// AES lookup values
static const uint8_t SBOX[256] =
{
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b,
0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26,
0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2,
0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed,
0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f,
0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec,
0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14,
0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d,
0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f,
0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11,
0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f,
0xb0, 0x54, 0xbb, 0x16
};
static const uint8_t RSBOX[256] =
{
0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e,
0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32,
0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49,
0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50,
0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05,
0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41,
0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8,
0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b,
0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59,
0x27, 0x80, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d,
0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63,
0x55, 0x21, 0x0c, 0x7d };
// The round constant word array, RCON[i], contains the values given by
// x to the power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
static const uint8_t RCON[11] =
{ 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
////////////////////////////////////////////////////////////////////////////////
// INTERNAL FUNCTIONS
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// KeyExpansion
//
// This function produces Nb(Nr+1) round keys. The round keys are used in each
// round to decrypt the states.
////////////////////////////////////////////////////////////////////////////////
static
void
KeyExpansion
(
uint8_t const* Key, // [in]
AesContext* Context // [in out]
)
{
uint32_t i;
uint8_t k;
uint8_t temp [4]; // Used for the column/row operations
// The first round key is the key itself.
for( i=0; iKeySizeInWords; i++ )
{
Context->RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
Context->RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
Context->RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
Context->RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
}
// All other round keys are found from the previous round keys.
for( i=Context->KeySizeInWords; i<4*(Context->NumberOfRounds+1); i++ )
{
#ifdef _MSC_VER
// Visual Studio code analysis complains about the following code
// that the index into Context->RoundKey may be -4. This is because
// it is concerned that 'i' may be zero. However we know that 'i'
// will not be zero as it starts at Context->KeySizeInWords which
// is never going to be zero when this function is called (It will
// have one of 3 values assigned to it by the initialise functions).
// So we need to just suppress the warning here to stop Visual
// Studio complaining.
#pragma warning( suppress : 6385 )
#endif
temp[0] = Context->RoundKey[(i-1) * 4 + 0];
temp[1] = Context->RoundKey[(i-1) * 4 + 1];
temp[2] = Context->RoundKey[(i-1) * 4 + 2];
temp[3] = Context->RoundKey[(i-1) * 4 + 3];
if( 0 == i % Context->KeySizeInWords )
{
// This function shifts the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
k = temp[0];
temp[0] = temp[1];
temp[1] = temp[2];
temp[2] = temp[3];
temp[3] = k;
// SubWord is a function that takes a four-byte input word and
// applies the S-box to each of the four bytes to produce an output
// word.
temp[0] = SBOX[temp[0]];
temp[1] = SBOX[temp[1]];
temp[2] = SBOX[temp[2]];
temp[3] = SBOX[temp[3]];
temp[0] = temp[0] ^ RCON[i/Context->KeySizeInWords];
}
if( AES_KEY_SIZE_256/4 == Context->KeySizeInWords )
{
// Only performed with 256 bit sized keys
if( 4 == i % Context->KeySizeInWords )
{
// Function Subword()
temp[0] = SBOX[temp[0]];
temp[1] = SBOX[temp[1]];
temp[2] = SBOX[temp[2]];
temp[3] = SBOX[temp[3]];
}
}
Context->RoundKey[i*4 + 0] =
Context->RoundKey[(i-Context->KeySizeInWords)*4 + 0] ^ temp[0];
Context->RoundKey[i*4 + 1] =
Context->RoundKey[(i-Context->KeySizeInWords)*4 + 1] ^ temp[1];
Context->RoundKey[i*4 + 2] =
Context->RoundKey[(i-Context->KeySizeInWords)*4 + 2] ^ temp[2];
Context->RoundKey[i*4 + 3] =
Context->RoundKey[(i-Context->KeySizeInWords)*4 + 3] ^ temp[3];
}
}
////////////////////////////////////////////////////////////////////////////////
// AddRoundKey
//
// This function adds the round key to state. The round key is added to the
// state by an XOR function.
////////////////////////////////////////////////////////////////////////////////
static
void
AddRoundKey
(
uint32_t Round, // [in]
AesContext const* Context, // [in]
AesState* State // [in out]
)
{
uint32_t i;
uint32_t j;
for( i=0; i<4; i++ )
{
for( j=0; j<4; j++ ) { State->state[i][j] ^= Context->RoundKey[(Round*4*4) + (i*4) + j];
}
}
}
////////////////////////////////////////////////////////////////////////////////
// SubBytes
//
// The SubBytes Function Substitutes the values in the state matrix with
// values in an S-box.
////////////////////////////////////////////////////////////////////////////////
static
void
SubBytes
(
AesState* State // [in out]
)
{
uint32_t i;
uint32_t j;
for( i=0; i<4; i++ )
{
for( j=0; j<4; j++ ) { State->state[j][i] = SBOX[ State->state[j][i] ];
}
}
}
////////////////////////////////////////////////////////////////////////////////
// ShiftRows
//
// The ShiftRows() function shifts the rows in the state to the left. Each row
// is shifted with different offset.
// Offset = Row number. So the first row is not shifted.
////////////////////////////////////////////////////////////////////////////////
static
void
ShiftRows
(
AesState* State // [in out]
)
{
uint8_t temp;
// Rotate first row 1 columns to left
temp = State->state[0][1];
State->state[0][1] = State->state[1][1];
State->state[1][1] = State->state[2][1];
State->state[2][1] = State->state[3][1];
State->state[3][1] = temp;
// Rotate second row 2 columns to left
temp = State->state[0][2];
State->state[0][2] = State->state[2][2];
State->state[2][2] = temp;
temp = State->state[1][2];
State->state[1][2] = State->state[3][2];
State->state[3][2] = temp;
// Rotate third row 3 columns to left
temp = State->state[0][3];
State->state[0][3] = State->state[3][3];
State->state[3][3] = State->state[2][3];
State->state[2][3] = State->state[1][3];
State->state[1][3] = temp;
}
////////////////////////////////////////////////////////////////////////////////
// xtime
//
// Performs a calculation
////////////////////////////////////////////////////////////////////////////////
static
uint8_t
xtime
(
uint8_t x // [in]
)
{
return (x<<1) ^ ( ((x>>7) & 1) * 0x1b );
}
////////////////////////////////////////////////////////////////////////////////
// MixColumns
//
// MixColumns function mixes the columns of the state matrix
////////////////////////////////////////////////////////////////////////////////
static
void
MixColumns
(
AesState* State // [in out]
)
{
uint32_t i;
uint8_t Tmp;
uint8_t Tm;
uint8_t t;
for( i=0; i<4; i++ ) { t = State->state[i][0];
Tmp = State->state[i][0] ^ State->state[i][1] ^ State->state[i][2]
^ State->state[i][3] ;
Tm = State->state[i][0] ^ State->state[i][1] ; Tm = xtime(Tm);
State->state[i][0] ^= Tm ^ Tmp ;
Tm = State->state[i][1] ^ State->state[i][2] ; Tm = xtime(Tm);
State->state[i][1] ^= Tm ^ Tmp ;
Tm = State->state[i][2] ^ State->state[i][3] ; Tm = xtime(Tm);
State->state[i][2] ^= Tm ^ Tmp ;
Tm = State->state[i][3] ^ t ; Tm = xtime(Tm);
State->state[i][3] ^= Tm ^ Tmp ;
}
}
////////////////////////////////////////////////////////////////////////////////
// Multiply
//
// Multiply is used to multiply numbers in the field GF(2^8). This is defined
// as a macro.
////////////////////////////////////////////////////////////////////////////////
#define Multiply(x, y) \
( ((y & 1) * x) ^ \
((y>>1 & 1) * xtime(x)) ^ \
((y>>2 & 1) * xtime(xtime(x))) ^ \
((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ \
((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))) \
////////////////////////////////////////////////////////////////////////////////
// InvMixColumns
//
// InvMixColumns function mixes the columns of the state matrix.
////////////////////////////////////////////////////////////////////////////////
static
void
InvMixColumns
(
AesState* State // [in out]
)
{
uint32_t i;
uint8_t a;
uint8_t b;
uint8_t c;
uint8_t d;
for( i=0; i<4; i++ ) { a = State->state[i][0];
b = State->state[i][1];
c = State->state[i][2];
d = State->state[i][3];
State->state[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b)
^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
State->state[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e)
^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
State->state[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09)
^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
State->state[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d)
^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
}
}
////////////////////////////////////////////////////////////////////////////////
// InvSubBytes
//
// The InvSubBytes Function Substitutes the values in the state matrix with
// values in an S-box.
////////////////////////////////////////////////////////////////////////////////
static
void
InvSubBytes
(
AesState* State // [in out]
)
{
uint32_t i;
uint32_t j;
for( i=0; i<4; i++ )
{
for( j=0; j<4; j++ )
{
State->state[j][i] = RSBOX[ State->state[j][i] ];
}
}
}
////////////////////////////////////////////////////////////////////////////////
// InvShiftRows
//
// Inverse of ShiftRows
////////////////////////////////////////////////////////////////////////////////
static
void
InvShiftRows
(
AesState* State // [in out]
)
{
uint8_t temp;
// Rotate first row 1 columns to right
temp = State->state[3][1];
State->state[3][1] = State->state[2][1];
State->state[2][1] = State->state[1][1];
State->state[1][1] = State->state[0][1];
State->state[0][1] = temp;
// Rotate second row 2 columns to right
temp = State->state[0][2];
State->state[0][2] = State->state[2][2];
State->state[2][2] = temp;
temp = State->state[1][2];
State->state[1][2] = State->state[3][2];
State->state[3][2] = temp;
// Rotate third row 3 columns to right
temp = State->state[0][3];
State->state[0][3] = State->state[1][3];
State->state[1][3] = State->state[2][3];
State->state[2][3] = State->state[3][3];
State->state[3][3] = temp;
}
////////////////////////////////////////////////////////////////////////////////
// EXPORTED FUNCTIONS
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
// AesInitialise128
//
// Initialises an AesContext with a 128 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise128
(
uint8_t const Key [AES_KEY_SIZE_128], // [in]
AesContext* Context // [out]
)
{
memset( Context, 0, sizeof(*Context) );
Context->KeySizeInWords = AES_KEY_SIZE_128 / sizeof(uint32_t);
Context->NumberOfRounds = 10;
KeyExpansion( Key, Context );
}
////////////////////////////////////////////////////////////////////////////////
// AesInitialise192
//
// Initialises an AesContext with a 192 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise192
(
uint8_t const Key [AES_KEY_SIZE_192], // [in]
AesContext* Context // [out]
)
{
memset( Context, 0, sizeof(*Context) );
Context->KeySizeInWords = AES_KEY_SIZE_192 / sizeof(uint32_t);
Context->NumberOfRounds = 12;
KeyExpansion( Key, Context );
}
////////////////////////////////////////////////////////////////////////////////
// AesInitialise256
//
// Initialises an AesContext with a 256 bit key.
////////////////////////////////////////////////////////////////////////////////
void
AesInitialise256
(
uint8_t const Key [AES_KEY_SIZE_256], // [in]
AesContext* Context // [out]
)
{
memset( Context, 0, sizeof(*Context) );
Context->KeySizeInWords = AES_KEY_SIZE_256 / sizeof(uint32_t);
Context->NumberOfRounds = 14;
KeyExpansion( Key, Context );
}
////////////////////////////////////////////////////////////////////////////////
// AesEncrypt
//
// Performs an AES encryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. Input and Output can
// point to same memory location, however it is more efficient to use
// AesEncryptInPlace in this situation.
////////////////////////////////////////////////////////////////////////////////
void
AesEncrypt
(
AesContext const* Context, // [in]
uint8_t const Input [AES_BLOCK_SIZE], // [in]
uint8_t Output [AES_BLOCK_SIZE] // [out]
)
{
memcpy( Output, Input, AES_BLOCK_SIZE );
AesEncryptInPlace( Context, Output );
}
////////////////////////////////////////////////////////////////////////////////
// AesDecrypt
//
// Performs an AES decryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. Input and Output can
// point to same memory location, however it is more efficient to use
// AesDecryptInPlace in this situation.
////////////////////////////////////////////////////////////////////////////////
void
AesDecrypt
(
AesContext const* Context, // [in]
uint8_t const Input [AES_BLOCK_SIZE], // [in]
uint8_t Output [AES_BLOCK_SIZE] // [out]
)
{
memcpy( Output, Input, AES_BLOCK_SIZE);
AesDecryptInPlace(Context, Output );
}
////////////////////////////////////////////////////////////////////////////////
// AesEncryptInPlace
//
// Performs an AES encryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. The encryption is
// performed in place.
////////////////////////////////////////////////////////////////////////////////
void
AesEncryptInPlace
(
AesContext const* Context, // [in]
uint8_t Block [AES_BLOCK_SIZE] // [in out]
)
{
uint32_t round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey( 0, Context, (AesState*)Block );
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for( round=1; roundNumberOfRounds; round++ )
{
SubBytes( (AesState*)Block );
ShiftRows( (AesState*)Block );
MixColumns( (AesState*)Block );
AddRoundKey( round, Context, (AesState*)Block );
}
// The last round is given below.
// The MixColumns function is not here in the last round.
SubBytes( (AesState*)Block);
ShiftRows( (AesState*)Block);
AddRoundKey( Context->NumberOfRounds, Context, (AesState*)Block );
}
////////////////////////////////////////////////////////////////////////////////
// AesDecryptInPlace
//
// Performs an AES decryption of one block (128 bits) with the AesContext
// initialised with one of the functions AesInitialise[n]. The decryption is
// performed in place.
////////////////////////////////////////////////////////////////////////////////
void
AesDecryptInPlace
(
AesContext const* Context, // [in]
uint8_t Block [AES_BLOCK_SIZE] // [in out]
)
{
uint32_t round = 0;
// Add the First round key to the state before starting the rounds.
AddRoundKey( Context->NumberOfRounds, Context, (AesState*)Block );
// The first NumberOfRounds-1 rounds are identical.
for( round=(Context->NumberOfRounds-1); round>0; round-- )
{
InvShiftRows( (AesState*)Block );
InvSubBytes( (AesState*)Block );
AddRoundKey( round, Context, (AesState*)Block );
InvMixColumns( (AesState*)Block );
}
// The MixColumns function is not here in the last round.
InvShiftRows( (AesState*)Block );
InvSubBytes( (AesState*)Block );
AddRoundKey( 0, Context, (AesState*)Block );
}
Water Juice 