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| -rw-r--r-- | aes_cbc.c | 581 |
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diff --git a/aes_cbc.c b/aes_cbc.c deleted file mode 100644 index 21c8430..0000000 --- a/aes_cbc.c +++ /dev/null @@ -1,581 +0,0 @@ -/* - -This is an implementation of the AES128 algorithm, specifically ECB and CBC mode. - -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. - -*/ - - -/*****************************************************************************/ -/* Includes: */ -/*****************************************************************************/ -#include <stdint.h> -#include <string.h> // CBC mode, for memset -#include "aes.h" - - -/*****************************************************************************/ -/* Defines: */ -/*****************************************************************************/ -// The number of columns comprising a state in AES. This is a constant in AES. Value=4 -#define Nb 4 -// The number of 32 bit words in a key. -#define Nk 4 -// Key length in bytes [128 bit] -#define KEYLEN 16 -// The number of rounds in AES Cipher. -#define Nr 10 - -// 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[176]; - -// The Key input to the AES Program -static const uint8_t* Key; - -// Initial Vector used for CBC mode etc. -static uint8_t* Iv; - -// 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) -// Note that i starts at 1, not 0). -static const uint8_t Rcon[255] = { - 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 }; - - -/*****************************************************************************/ -/* 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, j, k; - uint8_t 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. - for(; (i < (Nb * (Nr + 1))); ++i) - { - for(j = 0; j < 4; ++j) - { - tempa[j]=RoundKey[(i-1) * 4 + j]; - } - if (i % Nk == 0) - { - // This function rotates 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]; - } - else if (Nk > 6 && 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]); - } - } - 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 ((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) \ - ( ((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); -} - -static void BlockCopy(uint8_t* output, uint8_t* input) -{ - uint8_t i; - for (i=0;i<KEYLEN;++i) - { - output[i] = input[i]; - } -} - - - -/*****************************************************************************/ -/* Public functions: */ -/*****************************************************************************/ -#if defined(ECB) && ECB - - -void AES128_ECB_encrypt(uint8_t* input, const uint8_t* key, uint8_t* output) -{ - // Copy input to output, and work in-memory on output - BlockCopy(output, input); - state = (state_t*)output; - - Key = key; - KeyExpansion(); - - // The next function call encrypts the PlainText with the Key using AES algorithm. - Cipher(); -} - -void AES128_ECB_decrypt(uint8_t* input, const uint8_t* key, uint8_t *output) -{ - // Copy input to output, and work in-memory on output - BlockCopy(output, input); - state = (state_t*)output; - - // The KeyExpansion routine must be called before encryption. - Key = key; - KeyExpansion(); - - InvCipher(); -} - - -#endif // #if defined(ECB) && ECB - - - - - -#if defined(CBC) && CBC - - -static void XorWithIv(uint8_t* buf) -{ - uint8_t i; - for(i = 0; i < KEYLEN; ++i) - { - buf[i] ^= Iv[i]; - } -} - -void AES128_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv) -{ - intptr_t i; - uint8_t remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */ - - BlockCopy(output, input); - state = (state_t*)output; - - // 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 += KEYLEN) - { - XorWithIv(input); - BlockCopy(output, input); - state = (state_t*)output; - Cipher(); - Iv = output; - input += KEYLEN; - output += KEYLEN; - } - - if(remainders) - { - BlockCopy(output, input); - memset(output + remainders, 0, KEYLEN - remainders); /* add 0-padding */ - state = (state_t*)output; - Cipher(); - } -} - -void AES128_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, const uint8_t* key, const uint8_t* iv) -{ - intptr_t i; - uint8_t remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */ - - BlockCopy(output, input); - state = (state_t*)output; - - // 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 += KEYLEN) - { - BlockCopy(output, input); - state = (state_t*)output; - InvCipher(); - XorWithIv(output); - Iv = input; - input += KEYLEN; - output += KEYLEN; - } - - if(remainders) - { - BlockCopy(output, input); - memset(output+remainders, 0, KEYLEN - remainders); /* add 0-padding */ - state = (state_t*)output; - InvCipher(); - } -} - - -#endif // #if defined(CBC) && CBC - - |