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authorMatteo Brichese <matteo.brichese@wunderbar.com>2017-06-06 22:33:36 +0200
committerMatteo Brichese <matteo.brichese@wunderbar.com>2017-06-06 22:33:36 +0200
commitc1c5fb1974203abf974d6ad359f22dd64b203e45 (patch)
treed9c7994cb0d9c8e04b7c5a362ee9f1dfe8191a29
parentEncrypt CBC works (diff)
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-rw-r--r--aes.c30
-rw-r--r--aes.h2
-rw-r--r--test.c20
3 files changed, 29 insertions, 23 deletions
diff --git a/aes.c b/aes.c
index 6a2a531..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];
@@ -494,7 +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 < 16; ++i) //WAS for(i = 0; i < KEYLEN; ++i) but the block in AES is always 128bit so 16 bytes!
+ 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];
}
@@ -503,9 +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 extra = length % 16; /* Remaining bytes in the last non-full block */
+ uint8_t extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */
- memcpy(output, input, 16);
+ memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
// Skip the key expansion if key is passed as 0
@@ -520,21 +521,20 @@ 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 += 16)
+ for(i = 0; i < length; i += BLOCKLEN)
{
XorWithIv(input);
- memcpy(output, input, 16);
+ memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
Cipher();
Iv = output;
- input += 16;
- output += 16;
+ input += BLOCKLEN;
+ output += BLOCKLEN;
//printf("Step %d - %d", i/16, i);
}
if(extra)
{
- printf("NONO\n");
memcpy(output, input, extra);
state = (state_t*)output;
Cipher();
@@ -544,9 +544,9 @@ 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 extra = length % 16; /* Remaining bytes in the last non-full block */
+ uint8_t extra = length % BLOCKLEN; /* Remaining bytes in the last non-full block */
- memcpy(output, input, 16);
+ memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
// Skip the key expansion if key is passed as 0
@@ -562,15 +562,15 @@ 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 += 16)
+ for(i = 0; i < length; i += BLOCKLEN)
{
- memcpy(output, input, 16);
+ memcpy(output, input, BLOCKLEN);
state = (state_t*)output;
InvCipher();
XorWithIv(output);
Iv = input;
- input += 16;
- output += 16;
+ input += BLOCKLEN;
+ output += BLOCKLEN;
}
if(extra)
diff --git a/aes.h b/aes.h
index 15b504e..624b4ab 100644
--- a/aes.h
+++ b/aes.h
@@ -6,7 +6,7 @@
// #define the macros below to 1/0 to enable/disable the mode of operation.
//
-// CBC enables AES128 encryption in CBC-mode of operation and handles 0-padding.
+// CBC enables AES encryption in CBC-mode of operation.
// ECB enables the basic ECB 16-byte block algorithm. Both can be enabled simultaneously.
// The #ifndef-guard allows it to be configured before #include'ing or at compile time.
diff --git a/test.c b/test.c
index baf2219..8900e91 100644
--- a/test.c
+++ b/test.c
@@ -20,13 +20,18 @@ static void test_decrypt_cbc(void);
int main(void)
{
+
#ifdef AES128
- printf("\nAES128\n\n");
+ printf("\nTesting AES128\n\n");
#elif defined(AES192)
- printf("\nAES192\n\n");
+ printf("\nTesting AES192\n\n");
#elif defined(AES256)
- printf("\nAES256\n\n");
+ printf("\nTesting AES256\n\n");
+#else
+ printf("You need to specify a symbol between AES128, AES192 or AES256. Exiting");
+ return 0;
#endif
+
test_encrypt_cbc();
test_decrypt_cbc();
test_decrypt_ecb();
@@ -151,12 +156,13 @@ static void test_decrypt_cbc(void)
0x39, 0xf2, 0x33, 0x69, 0xa9, 0xd9, 0xba, 0xcf, 0xa5, 0x30, 0xe2, 0x63, 0x04, 0x23, 0x14, 0x61,
0xb2, 0xeb, 0x05, 0xe2, 0xc3, 0x9b, 0xe9, 0xfc, 0xda, 0x6c, 0x19, 0x07, 0x8c, 0x6a, 0x9d, 0x1b };
#endif
- uint8_t iv[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };
+ uint8_t iv[] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };
uint8_t out[] = { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96, 0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
- 0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c, 0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
- 0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11, 0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
- 0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17, 0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10 };
+ 0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c, 0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
+ 0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11, 0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
+ 0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17, 0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10 };
uint8_t buffer[64];
+ uint8_t buffer2[64];
AES_CBC_decrypt_buffer(buffer, in, 64, key, iv);