/* Source: https://github.com/kokke/tiny-AES-c This is an implementation of the AES algorithm, specifically ECB and CBC mode. Block size can be chosen in aes.h - available choices are AES128, AES192, AES256. The implementation is verified against the test vectors in: National Institute of Standards and Technology Special Publication 800-38A 2001 ED ECB-AES128 ---------- plain-text: 6bc1bee22e409f96e93d7e117393172a ae2d8a571e03ac9c9eb76fac45af8e51 30c81c46a35ce411e5fbc1191a0a52ef f69f2445df4f9b17ad2b417be66c3710 key: 2b7e151628aed2a6abf7158809cf4f3c resulting cipher 3ad77bb40d7a3660a89ecaf32466ef97 f5d3d58503b9699de785895a96fdbaaf 43b1cd7f598ece23881b00e3ed030688 7b0c785e27e8ad3f8223207104725dd4 NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0) You should pad the end of the string with zeros if this is not the case. For AES192/256 the block size is proportionally larger. */ /*****************************************************************************/ /* Includes: */ /*****************************************************************************/ #include #include "aes.h" /*****************************************************************************/ /* Defines: */ /*****************************************************************************/ // The number of columns comprising a state in AES. This is a constant in AES. Value=4 #define Nb 4 #if defined(AES_256) && (AES_256 == 1) #define Nk 8 #define KEYLEN 32 #define Nr 14 #define keyExpSize 240 #elif defined(AES_192) && (AES_192 == 1) #define Nk 6 #define KEYLEN 24 #define Nr 12 #define keyExpSize 208 #elif defined(AES_128) && (AES_128 == 1) #define Nk 4 // The number of 32 bit words in a key. #define KEYLEN 16 // Key length in bytes #define Nr 10 // The number of rounds in AES Cipher. #define keyExpSize 176 #else #error Must define either AES_128, AES_192 or AES_256. #endif // jcallan@github points out that declaring Multiply as a function // reduces code size considerably with the Keil ARM compiler. // See this link for more information: https://github.com/kokke/tiny-AES128-C/pull/3 #ifndef MULTIPLY_AS_A_FUNCTION #define MULTIPLY_AS_A_FUNCTION 0 #endif /*****************************************************************************/ /* Private variables: */ /*****************************************************************************/ // state - array holding the intermediate results during decryption. typedef uint8_t state_t[4][4]; static state_t* state; // The array that stores the round keys. static uint8_t RoundKey[keyExpSize]; // The Key input to the AES Program static const uint8_t* Key; #if defined(AES_CBC) && AES_CBC // Initial Vector used only for CBC mode static uint8_t* Iv; #endif // The lookup-tables are marked const so they can be placed in read-only storage instead of RAM // The numbers below can be computed dynamically trading ROM for RAM - // This can be useful in (embedded) bootloader applications, where ROM is often limited. static const uint8_t sbox[256] = { //0 1 2 3 4 5 6 7 8 9 A B C D E F 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 th e 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 }; /* * Jordan Goulder points out in PR #12 (https://github.com/kokke/tiny-AES128-C/pull/12), * that you can remove most of the elements in the Rcon array, because they are unused. * * From Wikipedia's article on the Rijndael key schedule @ https://en.wikipedia.org/wiki/Rijndael_key_schedule#Rcon * * "Only the first some of these constants are actually used – up to rcon[10] for AES-128 (as 11 round keys are needed), * up to rcon[8] for AES-192, up to rcon[7] for AES-256. rcon[0] is not used in AES algorithm." * * ... which is why the full array below has been 'disabled' below. */ #if 0 static const uint8_t Rcon[256] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d }; #endif /*****************************************************************************/ /* Private functions: */ /*****************************************************************************/ static uint8_t getSBoxValue(uint8_t num) { return sbox[num]; } static uint8_t getSBoxInvert(uint8_t num) { return rsbox[num]; } // This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states. static void KeyExpansion(void) { uint32_t i; uint8_t k, tempa[4]; // Used for the column/row operations // The first round key is the key itself. for (i = 0; i < Nk; ++i) { RoundKey[(i * 4) + 0] = Key[(i * 4) + 0]; RoundKey[(i * 4) + 1] = Key[(i * 4) + 1]; RoundKey[(i * 4) + 2] = Key[(i * 4) + 2]; RoundKey[(i * 4) + 3] = Key[(i * 4) + 3]; } // All other round keys are found from the previous round keys. //i == Nk for (; i < Nb * (Nr + 1); ++i) { { tempa[0]=RoundKey[(i-1) * 4 + 0]; tempa[1]=RoundKey[(i-1) * 4 + 1]; tempa[2]=RoundKey[(i-1) * 4 + 2]; tempa[3]=RoundKey[(i-1) * 4 + 3]; } if (i % Nk == 0) { // This function shifts the 4 bytes in a word to the left once. // [a0,a1,a2,a3] becomes [a1,a2,a3,a0] // Function RotWord() { k = tempa[0]; tempa[0] = tempa[1]; tempa[1] = tempa[2]; tempa[2] = tempa[3]; tempa[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. // Function Subword() { tempa[0] = getSBoxValue(tempa[0]); tempa[1] = getSBoxValue(tempa[1]); tempa[2] = getSBoxValue(tempa[2]); tempa[3] = getSBoxValue(tempa[3]); } tempa[0] = tempa[0] ^ Rcon[i/Nk]; } #if defined(AES256) && (AES256 == 1) if (i % Nk == 4) { // Function Subword() { tempa[0] = getSBoxValue(tempa[0]); tempa[1] = getSBoxValue(tempa[1]); tempa[2] = getSBoxValue(tempa[2]); tempa[3] = getSBoxValue(tempa[3]); } } #endif RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0]; RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1]; RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2]; RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3]; } } // This function adds the round key to state. // The round key is added to the state by an XOR function. static void AddRoundKey(uint8_t round) { uint8_t i,j; for (i=0;i<4;++i) { for (j = 0; j < 4; ++j) { (*state)[i][j] ^= RoundKey[round * Nb * 4 + i * Nb + j]; } } } // The SubBytes Function Substitutes the values in the // state matrix with values in an S-box. static void SubBytes(void) { uint8_t i, j; for (i = 0; i < 4; ++i) { for (j = 0; j < 4; ++j) { (*state)[j][i] = getSBoxValue((*state)[j][i]); } } } // 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(void) { uint8_t temp; // Rotate first row 1 columns to left 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; // Rotate second row 2 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; // Rotate third row 3 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; } static uint8_t xtime(uint8_t x) { return (uint8_t)((x << 1) ^ (((x >> 7) & 1) * 0x1b)); } // MixColumns function mixes the columns of the state matrix static void MixColumns(void) { uint8_t i; uint8_t Tmp,Tm,t; for (i = 0; i < 4; ++i) { t = (*state)[i][0]; Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3] ; Tm = (*state)[i][0] ^ (*state)[i][1] ; Tm = xtime(Tm); (*state)[i][0] ^= Tm ^ Tmp ; Tm = (*state)[i][1] ^ (*state)[i][2] ; Tm = xtime(Tm); (*state)[i][1] ^= Tm ^ Tmp ; Tm = (*state)[i][2] ^ (*state)[i][3] ; Tm = xtime(Tm); (*state)[i][2] ^= Tm ^ Tmp ; Tm = (*state)[i][3] ^ t ; Tm = xtime(Tm); (*state)[i][3] ^= Tm ^ Tmp ; } } // Multiply is used to multiply numbers in the field GF(2^8) #if MULTIPLY_AS_A_FUNCTION static uint8_t Multiply(uint8_t x, uint8_t y) { return (((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)))))); } #else #define Multiply(x, y) (uint8_t) \ ( ((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)))))) \ #endif // MixColumns function mixes the columns of the state matrix. // The method used to multiply may be difficult to understand for the inexperienced. // Please use the references to gain more information. static void InvMixColumns(void) { int i; uint8_t a, b, c, d; for (i = 0; i < 4; ++i) { a = (*state)[i][0]; b = (*state)[i][1]; c = (*state)[i][2]; d = (*state)[i][3]; (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09); (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d); (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b); (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e); } } // The SubBytes Function Substitutes the values in the // state matrix with values in an S-box. static void InvSubBytes(void) { uint8_t i,j; for (i = 0; i < 4; ++i) { for (j = 0; j < 4; ++j) { (*state)[j][i] = getSBoxInvert((*state)[j][i]); } } } static void InvShiftRows(void) { uint8_t temp; // Rotate first row 1 columns to right 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; // Rotate second row 2 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; // Rotate third row 3 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; } // Cipher is the main function that encrypts the PlainText. static void Cipher(void) { uint8_t round = 0; // Add the First round key to the state before starting the rounds. AddRoundKey(0); // 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; round < Nr; ++round) { SubBytes(); ShiftRows(); MixColumns(); AddRoundKey(round); } // The last round is given below. // The MixColumns function is not here in the last round. SubBytes(); ShiftRows(); AddRoundKey(Nr); } static void InvCipher(void) { uint8_t round=0; // Add the First round key to the state before starting the rounds. AddRoundKey(Nr); // There will be Nr rounds. // The first Nr-1 rounds are identical. // These Nr-1 rounds are executed in the loop below. for (round = (Nr - 1); round > 0; --round) { InvShiftRows(); InvSubBytes(); AddRoundKey(round); InvMixColumns(); } // The last round is given below. // The MixColumns function is not here in the last round. InvShiftRows(); InvSubBytes(); AddRoundKey(0); } /*****************************************************************************/ /* Public functions: */ /*****************************************************************************/ #if defined(AES_ECB) && (AES_ECB == 1) void AES_ECB_encrypt(uint8_t *output, const uint8_t *input, const uint32_t length, const uint8_t *key) { // Copy input to output, and work in-memory on output memcpy(output, input, length); state = (state_t*)output; Key = key; KeyExpansion(); // The next function call encrypts the PlainText with the Key using AES algorithm. Cipher(); bzero( RoundKey, keyExpSize ); } void AES_ECB_decrypt(uint8_t *output, const uint8_t *input, const uint32_t length, const uint8_t *key) { // Copy input to output, and work in-memory on output memcpy(output, input, length); state = (state_t*)output; // The KeyExpansion routine must be called before encryption. Key = key; KeyExpansion(); InvCipher(); bzero( RoundKey, keyExpSize ); } #endif // #if defined(AES_ECB) && (AES_ECB == 1) #if defined(AES_CBC) && (AES_CBC == 1) static void XorWithIv(uint8_t* buf) { uint8_t i; for (i = 0; i < AES_BLOCKLEN; ++i) //WAS for(i = 0; i < KEYLEN; ++i) but the block in AES is always 128bit so 16 bytes! { buf[i] ^= Iv[i]; } } void AES_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv) { uintptr_t i; uint8_t extra = (uint8_t)(length % AES_BLOCKLEN); /* Remaining bytes in the last non-full block */ // Skip the key expansion if key is passed as 0 if (0 != key) { Key = key; KeyExpansion(); } if (iv != 0) { Iv = (uint8_t*)iv; } for (i = 0; i < length; i += AES_BLOCKLEN) { XorWithIv(input); memcpy(output, input, AES_BLOCKLEN); state = (state_t*)output; Cipher(); Iv = output; input += AES_BLOCKLEN; output += AES_BLOCKLEN; //printf("Step %d - %d", i/16, i); } if (extra) { memcpy(output, input, extra); state = (state_t*)output; Cipher(); } bzero( RoundKey, keyExpSize ); } void AES_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv) { uintptr_t i; uint8_t extra = (uint8_t)(length % AES_BLOCKLEN); /* Remaining bytes in the last non-full block */ // Skip the key expansion if key is passed as 0 if (0 != key) { Key = key; KeyExpansion(); } // If iv is passed as 0, we continue to encrypt without re-setting the Iv if (iv != 0) { Iv = (uint8_t*)iv; } for (i = 0; i < length; i += AES_BLOCKLEN) { memcpy(output, input, AES_BLOCKLEN); state = (state_t*)output; InvCipher(); XorWithIv(output); Iv = input; input += AES_BLOCKLEN; output += AES_BLOCKLEN; } if (extra) { memcpy(output, input, extra); state = (state_t*)output; InvCipher(); } bzero( RoundKey, keyExpSize ); } #endif // #if defined(AES_CBC) && (AES_CBC == 1)