added AES192 and 256

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;
+    input += BLOCKLEN;
-    output += 16;
+    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;
+    input += BLOCKLEN;
-    output += 16;
+    output += BLOCKLEN;
   }
 
   if(extra)

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.

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,
+                     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,
+                     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 };
+                     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);