diff options
Diffstat (limited to 'aes.c')
| -rw-r--r-- | aes.c | 62 |
1 files changed, 26 insertions, 36 deletions
@@ -42,6 +42,7 @@ NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0) /*****************************************************************************/ // The number of columns comprising a state in AES. This is a constant in AES. Value=4 #define Nb 4 +#define BLOCKLEN 16 //Block length in bytes AES is 128b block only #ifdef AES256 #define Nk 8 @@ -177,7 +178,7 @@ static void KeyExpansion(void) // All other round keys are found from the previous round keys. //i == Nk - for(i = Nk; i < Nb * (Nr + 1); ++i) + for(; i < Nb * (Nr + 1); ++i) { { tempa[0]=RoundKey[(i-1) * 4 + 0]; @@ -448,16 +449,6 @@ static void InvCipher(void) AddRoundKey(0); } -static void BlockCopy(uint8_t* output, const uint8_t* input) -{ - uint8_t i; - for (i=0;i<KEYLEN;++i) - { - output[i] = input[i]; - } -} - - /*****************************************************************************/ /* Public functions: */ @@ -465,10 +456,10 @@ static void BlockCopy(uint8_t* output, const uint8_t* input) #if defined(ECB) && ECB -void AES_ECB_encrypt(const uint8_t* input, const uint8_t* key, uint8_t* output) +void AES_ECB_encrypt(const uint8_t* input, const uint8_t* key, uint8_t* output, const uint32_t length) { // Copy input to output, and work in-memory on output - BlockCopy(output, input); + memcpy(output, input, length); state = (state_t*)output; Key = key; @@ -478,10 +469,10 @@ void AES_ECB_encrypt(const uint8_t* input, const uint8_t* key, uint8_t* output) Cipher(); } -void AES_ECB_decrypt(const uint8_t* input, const uint8_t* key, uint8_t *output) +void AES_ECB_decrypt(const uint8_t* input, const uint8_t* key, uint8_t *output, const uint32_t length) { // Copy input to output, and work in-memory on output - BlockCopy(output, input); + memcpy(output, input, length); state = (state_t*)output; // The KeyExpansion routine must be called before encryption. @@ -504,7 +495,7 @@ void AES_ECB_decrypt(const uint8_t* input, const uint8_t* key, uint8_t *output) static void XorWithIv(uint8_t* buf) { uint8_t i; - for(i = 0; i < KEYLEN; ++i) + for(i = 0; i < BLOCKLEN; ++i) //WAS for(i = 0; i < KEYLEN; ++i) but the block in AES is always 128bit so 16 bytes! { buf[i] ^= Iv[i]; } @@ -513,9 +504,9 @@ static void XorWithIv(uint8_t* buf) 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 remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */ + uint8_t extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */ - BlockCopy(output, input); + memcpy(output, input, BLOCKLEN); state = (state_t*)output; // Skip the key expansion if key is passed as 0 @@ -530,21 +521,21 @@ void AES_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, co Iv = (uint8_t*)iv; } - for(i = 0; i < length; i += KEYLEN) + for(i = 0; i < length; i += BLOCKLEN) { XorWithIv(input); - BlockCopy(output, input); + memcpy(output, input, BLOCKLEN); state = (state_t*)output; Cipher(); Iv = output; - input += KEYLEN; - output += KEYLEN; + input += BLOCKLEN; + output += BLOCKLEN; + //printf("Step %d - %d", i/16, i); } - if(remainders) + if(extra) { - BlockCopy(output, input); - memset(output + remainders, 0, KEYLEN - remainders); /* add 0-padding */ + memcpy(output, input, extra); state = (state_t*)output; Cipher(); } @@ -553,11 +544,11 @@ void AES_CBC_encrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, co 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 remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */ - - BlockCopy(output, input); - state = (state_t*)output; + uint8_t extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */ + memcpy(output, input, BLOCKLEN); + state = (state_t*)output; + // Skip the key expansion if key is passed as 0 if(0 != key) { @@ -571,21 +562,20 @@ void AES_CBC_decrypt_buffer(uint8_t* output, uint8_t* input, uint32_t length, co Iv = (uint8_t*)iv; } - for(i = 0; i < length; i += KEYLEN) + for(i = 0; i < length; i += BLOCKLEN) { - BlockCopy(output, input); + memcpy(output, input, BLOCKLEN); state = (state_t*)output; InvCipher(); XorWithIv(output); Iv = input; - input += KEYLEN; - output += KEYLEN; + input += BLOCKLEN; + output += BLOCKLEN; } - if(remainders) + if(extra) { - BlockCopy(output, input); - memset(output+remainders, 0, KEYLEN - remainders); /* add 0-padding */ + memcpy(output, input, extra); state = (state_t*)output; InvCipher(); } |