1、aes256cbc.h
#ifndef _AES256CBC_H_ #define _AES256CBC_H_ #define AES_BLOCKLEN 16 #define AES_KEYLEN 32 #define AES_keyExpSize 240 struct AES_ctx { unsigned char RoundKey[AES_keyExpSize]; unsigned char Iv[AES_BLOCKLEN]; }; void AES256CBC_init_ctx_iv(struct AES_ctx* ctx, const unsigned char* key, const unsigned char* iv); void AES256CBC_encrypt(struct AES_ctx* ctx, unsigned char* buf, unsigned int length); void AES256CBC_decrypt(struct AES_ctx* ctx, unsigned char* buf, unsigned int length); #endif
2、aes256cbc.c
#include <string.h> #include "aes256cbc.h" #define Nb 4 #define Nk 8 #define Nr 14 #ifndef MULTIPLY_AS_A_FUNCTION #define MULTIPLY_AS_A_FUNCTION 0 #endif typedef unsigned char state_t[4][4]; // 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 unsigned char 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 unsigned char 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 }; static const unsigned char Rcon[11] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; #define getSBoxValue(num) (sbox[(num)]) #define getSBoxInvert(num) (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(unsigned char* RoundKey, const unsigned char* Key) { unsigned i, j, k; unsigned char 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 = Nk; i < Nb * (Nr + 1); ++i) { { k = (i - 1) * 4; tempa[0]=RoundKey[k + 0]; tempa[1]=RoundKey[k + 1]; tempa[2]=RoundKey[k + 2]; tempa[3]=RoundKey[k + 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() { const unsigned char u8tmp = tempa[0]; tempa[0] = tempa[1]; tempa[1] = tempa[2]; tempa[2] = tempa[3]; tempa[3] = u8tmp; } // 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 (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]); } } j = i * 4; k=(i - Nk) * 4; RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0]; RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1]; RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2]; RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3]; } } void AES256CBC_init_ctx_iv(struct AES_ctx* ctx, const unsigned char* key, const unsigned char* iv) { KeyExpansion(ctx->RoundKey, key); memcpy (ctx->Iv, iv, AES_BLOCKLEN); } static void AddRoundKey(unsigned char round, state_t* state, const unsigned char* RoundKey) { unsigned char 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(state_t* state) { unsigned char 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(state_t* state) { unsigned char 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 unsigned char xtime(unsigned char x) { return ((x<<1) ^ (((x>>7) & 1) * 0x1b)); } // MixColumns function mixes the columns of the state matrix static void MixColumns(state_t* state) { unsigned char i; unsigned char 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 ; } } #if MULTIPLY_AS_A_FUNCTION static unsigned char Multiply(unsigned char x, unsigned char 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)))))); /* this last call to xtime() can be omitted */ } #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 static void InvMixColumns(state_t* state) { int i; unsigned char 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); } } static void InvSubBytes(state_t* state) { unsigned char i, j; for (i = 0; i < 4; ++i) { for (j = 0; j < 4; ++j) { (*state)[j][i] = getSBoxInvert((*state)[j][i]); } } } static void InvShiftRows(state_t* state) { unsigned char 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; } static void Cipher(state_t* state, const unsigned char* RoundKey) { unsigned char round = 0; // Add the First round key to the state before starting the rounds. AddRoundKey(0, state, RoundKey); // 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(state); ShiftRows(state); MixColumns(state); AddRoundKey(round, state, RoundKey); } // The last round is given below. // The MixColumns function is not here in the last round. SubBytes(state); ShiftRows(state); AddRoundKey(Nr, state, RoundKey); } static void InvCipher(state_t* state, const unsigned char* RoundKey) { unsigned char round = 0; // Add the First round key to the state before starting the rounds. AddRoundKey(Nr, state, RoundKey); // 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(state); InvSubBytes(state); AddRoundKey(round, state, RoundKey); InvMixColumns(state); } // The last round is given below. // The MixColumns function is not here in the last round. InvShiftRows(state); InvSubBytes(state); AddRoundKey(0, state, RoundKey); } static void XorWithIv(unsigned char* buf, const unsigned char* Iv) { unsigned char i; for (i = 0; i < AES_BLOCKLEN; ++i) // The block in AES is always 128bit no matter the key size { buf[i] ^= Iv[i]; } } void AES256CBC_encrypt(struct AES_ctx *ctx, unsigned char* buf, unsigned int length) { unsigned int i; unsigned char *Iv = ctx->Iv; for (i = 0; i < length; i += AES_BLOCKLEN) { XorWithIv(buf, Iv); Cipher((state_t*)buf, ctx->RoundKey); Iv = buf; buf += AES_BLOCKLEN; //printf("Step %d - %d", i/16, i); } /* store Iv in ctx for next call */ memcpy(ctx->Iv, Iv, AES_BLOCKLEN); } void AES256CBC_decrypt(struct AES_ctx* ctx, unsigned char* buf, unsigned int length) { unsigned int i; unsigned char storeNextIv[AES_BLOCKLEN]; for (i = 0; i < length; i += AES_BLOCKLEN) { memcpy(storeNextIv, buf, AES_BLOCKLEN); InvCipher((state_t*)buf, ctx->RoundKey); XorWithIv(buf, ctx->Iv); memcpy(ctx->Iv, storeNextIv, AES_BLOCKLEN); buf += AES_BLOCKLEN; } }
test
#include <stdio.h> #include <string.h> #include "aes256cbc.h" #define IV_LEN 16 #define KEY_LEN 32 //256 bit #define DATA_LEN 64 //data length must be : length % 16 == 0 and less than 4G Bytes int main() { unsigned char iv[IV_LEN] = { 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff }; unsigned char key[KEY_LEN] = { 0x60, 0x3d, 0xeb, 0x10, 0x15, 0xca, 0x71, 0xbe, 0x2b, 0x73, 0xae, 0xf0, 0x85, 0x7d, 0x77, 0x81, 0x1f, 0x35, 0x2c, 0x07, 0x3b, 0x61, 0x08, 0xd7, 0x2d, 0x98, 0x10, 0xa3, 0x09, 0x14, 0xdf, 0xf4 }; unsigned char data[DATA_LEN] = {0x60, 0x1e, 0xc3, 0x13, 0x77, 0x57, 0x89, 0xa5, 0xb7, 0xa7, 0xf5, 0x04, 0xbb, 0xf3, 0xd2, 0x28, 0xf4, 0x43, 0xe3, 0xca, 0x4d, 0x62, 0xb5, 0x9a, 0xca, 0x84, 0xe9, 0x90, 0xca, 0xca, 0xf5, 0xc5, 0x2b, 0x09, 0x30, 0xda, 0xa2, 0x3d, 0xe9, 0x4c, 0xe8, 0x70, 0x17, 0xba, 0x2d, 0x84, 0x98, 0x8d, 0xdf, 0xc9, 0xc5, 0x8d, 0xb6, 0x7a, 0xad, 0xa6, 0x13, 0xc2, 0xdd, 0x08, 0x45, 0x79, 0x41, 0xa6 }; //compare with openssl /*AES_KEY aes_key; unsigned char data_in[DATA_LEN]; unsigned char data_out[DATA_LEN]; unsigned char iv_in[IV_LEN]; memcpy(data_in,data,DATA_LEN); AES_set_encrypt_key(key, KEY_LEN*8, &aes_key);// 2nd parameter is bits of key length memcpy(iv_in,iv,IV_LEN); AES_cbc_encrypt(data_in,data_out,DATA_LEN,&aes_key,iv_in,AES_ENCRYPT); //-------------------------------------------------------------------------// AES_set_decrypt_key(key, KEY_LEN*8, &aes_key); memcpy(iv_in,iv,IV_LEN); AES_cbc_encrypt(data_out, data_in, DATA_LEN, &aes_key, iv_in, AES_DECRYPT); //end compare with openssl */ //begin test struct AES_ctx ctx; AES256CBC_init_ctx_iv(&ctx, key, iv); AES256CBC_encrypt(&ctx, data, DATA_LEN); //must re-initiate after use key and iv AES256CBC_init_ctx_iv(&ctx, key, iv); AES256CBC_decrypt(&ctx, data, DATA_LEN); return 0; }
