Diff: hmac/hmac-sha1.c

Revision:

7:94ef5824c3c0

Child:

9:f354b4859b0b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hmac/hmac-sha1.c	Thu Sep 05 12:58:41 2019 +0000
@@ -0,0 +1,90 @@
+#include <stdint.h>
+
+#include "hmac-sha1.h"
+#include "sha1.h"
+
+#define BLOCK_SIZE 64
+#define  HASH_SIZE 20
+
+void HmacSha1(const uint8_t* key, int keyLength, const uint8_t* message, int messageLength, uint8_t* mac)
+{
+    uint8_t hmacKey[BLOCK_SIZE];
+    
+    //Make the key BLOCK_SIZE bytes long by hashing longer ones or padding shorter one with 0s
+    if (keyLength > BLOCK_SIZE)
+    {
+        Sha1(key, keyLength, hmacKey);
+        for (int i = HASH_SIZE; i < BLOCK_SIZE; i++) hmacKey[i] = 0;
+    }
+    else
+    {
+        for (int i = 0;         i < keyLength;  i++) hmacKey[i] = key[i];
+        for (int i = keyLength; i < BLOCK_SIZE; i++) hmacKey[i] = 0;
+    }
+    
+    //Make the inner and outer padded keys
+    uint8_t oKeyPad[BLOCK_SIZE];
+    uint8_t iKeyPad[BLOCK_SIZE];
+    for (int i = 0; i < BLOCK_SIZE; i++)
+    {
+        oKeyPad[i] = hmacKey[i] ^ 0x5c; //Outer padded key
+        iKeyPad[i] = hmacKey[i] ^ 0x36; //Inner padded key
+    }
+    
+    //hash(o_key_pad + hash(i_key_pad + message) where + is concatenation
+    uint8_t* tempi = alloca(BLOCK_SIZE + messageLength);
+    for (int i = 0; i < BLOCK_SIZE;    i++) tempi[i             ] = iKeyPad[i];
+    for (int i = 0; i < messageLength; i++) tempi[i + BLOCK_SIZE] = message[i];
+    uint8_t tmpHash[HASH_SIZE];
+    Sha1(tempi, BLOCK_SIZE + messageLength, tmpHash);
+    
+    uint8_t tmpMsg[BLOCK_SIZE + HASH_SIZE];
+    for (int i = 0; i < BLOCK_SIZE; i++) tmpMsg[i             ] = oKeyPad[i];
+    for (int i = 0; i <  HASH_SIZE; i++) tmpMsg[i + BLOCK_SIZE] = tmpHash[i];
+    Sha1(tmpMsg, BLOCK_SIZE + HASH_SIZE, mac);
+}
+void HmacSha1Start(struct HmacSha1Struct* md, const uint8_t* key, int keyLength)
+{
+    //Make the key BLOCK_SIZE bytes long by hashing longer ones or padding shorter one with 0s
+    if (keyLength > BLOCK_SIZE)
+    {
+        Sha1(key, keyLength, md->hmacKey);
+        for (int i = HASH_SIZE; i < BLOCK_SIZE; i++) md->hmacKey[i] = 0;
+    }
+    else
+    {
+        for (int i = 0;         i < keyLength;  i++) md->hmacKey[i] = key[i];
+        for (int i = keyLength; i < BLOCK_SIZE; i++) md->hmacKey[i] = 0;
+    }
+    Sha1Start(&md->shaStruct);
+    
+    //Make the inner and outer padded keys
+    uint8_t iKeyPad[BLOCK_SIZE];
+    for (int i = 0; i < BLOCK_SIZE; i++)
+    {
+        iKeyPad[i] = md->hmacKey[i] ^ 0x36; //Inner padded key
+    }
+    Sha1Add(&md->shaStruct, iKeyPad, BLOCK_SIZE);
+}
+void HmacSha1Add(struct HmacSha1Struct* md, const uint8_t* message, int messageLength)
+{
+    Sha1Add(&md->shaStruct, message, messageLength);
+}
+void HmacSha1Finish(struct HmacSha1Struct* md, uint8_t* mac)
+{
+    //Make the inner and outer padded keys
+    uint8_t oKeyPad[BLOCK_SIZE];
+    for (int i = 0; i < BLOCK_SIZE; i++)
+    {
+        oKeyPad[i] = md->hmacKey[i] ^ 0x5c; //Outer padded key
+    }
+    
+    uint8_t innerHash[HASH_SIZE];
+    Sha1Finish(&md->shaStruct, innerHash);
+    
+    Sha1Start(&md->shaStruct);
+    Sha1Add(&md->shaStruct, oKeyPad, BLOCK_SIZE);
+    Sha1Add(&md->shaStruct, innerHash, HASH_SIZE);
+    
+    Sha1Finish(&md->shaStruct, mac);
+}
\ No newline at end of file