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authorMatteo Brichese <bricke@users.noreply.github.com>2017-06-06 22:35:21 +0200
committerGitHub <noreply@github.com>2017-06-06 22:35:21 +0200
commit7fbaf55246306046255452acbb439445c2807939 (patch)
treed9c7994cb0d9c8e04b7c5a362ee9f1dfe8191a29 /aes.c
parentMerge branch 'master' of https://github.com/bricke/tiny-AES128-C (diff)
parentadded AES192 and 256 (diff)
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Diffstat (limited to 'aes.c')
-rw-r--r--aes.c62
1 files changed, 26 insertions, 36 deletions
diff --git a/aes.c b/aes.c
index bb026fd..e58498f 100644
--- a/aes.c
+++ b/aes.c
@@ -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();
}