Add HMAC support to all of the hash algorithms

libraries/Crypto/examples/TestSHA1/TestSHA1.ino

@@ -29,16 +29,19 @@ This example runs tests on the SHA1 implementation to verify correct behaviour.
 #include <string.h>
 
 #define HASH_SIZE 20
+#define BLOCK_SIZE 64
 
 struct TestHashVector
 {
     const char *name;
+    const char *key;
     const char *data;
     uint8_t hash[HASH_SIZE];
 };
 
 static TestHashVector const testVectorSHA1_1 = {
     "SHA-1 #1",
+    0,
     "abc",
     {0xA9, 0x99, 0x3E, 0x36, 0x47, 0x06, 0x81, 0x6A,
      0xBA, 0x3E, 0x25, 0x71, 0x78, 0x50, 0xC2, 0x6C,
@@ -46,11 +49,28 @@ static TestHashVector const testVectorSHA1_1 = {
 };
 static TestHashVector const testVectorSHA1_2 = {
     "SHA-1 #2",
+    0,
     "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
     {0x84, 0x98, 0x3E, 0x44, 0x1C, 0x3B, 0xD2, 0x6E,
      0xBA, 0xAE, 0x4A, 0xA1, 0xF9, 0x51, 0x29, 0xE5,
      0xE5, 0x46, 0x70, 0xF1}
 };
+static TestHashVector const testVectorHMAC_SHA1_1 = {
+    "HMAC-SHA-1 #1",
+    "",
+    "",
+    {0xfb, 0xdb, 0x1d, 0x1b, 0x18, 0xaa, 0x6c, 0x08,
+     0x32, 0x4b, 0x7d, 0x64, 0xb7, 0x1f, 0xb7, 0x63,
+     0x70, 0x69, 0x0e, 0x1d}
+};
+static TestHashVector const testVectorHMAC_SHA1_2 = {
+    "HMAC-SHA-1 #2",
+    "key",
+    "The quick brown fox jumps over the lazy dog",
+    {0xde, 0x7c, 0x9b, 0x85, 0xb8, 0xb7, 0x8a, 0xa6,
+     0xbc, 0x8a, 0x7a, 0x36, 0xf7, 0x0a, 0x90, 0x70,
+     0x1c, 0x9d, 0xb4, 0xd9}
+};
 
 SHA1 sha1;
 
@@ -100,6 +120,86 @@ void testHash(Hash *hash, const struct TestHashVector *test)
         Serial.println("Failed");
 }
 
+// Very simple method for hashing a HMAC inner or outer key.
+void hashKey(Hash *hash, const uint8_t *key, size_t keyLen, uint8_t pad)
+{
+    size_t posn;
+    uint8_t buf;
+    uint8_t result[HASH_SIZE];
+    if (keyLen <= BLOCK_SIZE) {
+        hash->reset();
+        for (posn = 0; posn < BLOCK_SIZE; ++posn) {
+            if (posn < keyLen)
+                buf = key[posn] ^ pad;
+            else
+                buf = pad;
+            hash->update(&buf, 1);
+        }
+    } else {
+        hash->reset();
+        hash->update(key, keyLen);
+        hash->finalize(result, HASH_SIZE);
+        hash->reset();
+        for (posn = 0; posn < BLOCK_SIZE; ++posn) {
+            if (posn < HASH_SIZE)
+                buf = result[posn] ^ pad;
+            else
+                buf = pad;
+            hash->update(&buf, 1);
+        }
+    }
+}
+
+void testHMAC(Hash *hash, size_t keyLen)
+{
+    uint8_t result[HASH_SIZE];
+
+    Serial.print("HMAC-SHA-1 keysize=");
+    Serial.print(keyLen);
+    Serial.print(" ... ");
+
+    // Construct the expected result with a simple HMAC implementation.
+    memset(buffer, (uint8_t)keyLen, keyLen);
+    hashKey(hash, buffer, keyLen, 0x36);
+    memset(buffer, 0xBA, sizeof(buffer));
+    hash->update(buffer, sizeof(buffer));
+    hash->finalize(result, HASH_SIZE);
+    memset(buffer, (uint8_t)keyLen, keyLen);
+    hashKey(hash, buffer, keyLen, 0x5C);
+    hash->update(result, HASH_SIZE);
+    hash->finalize(result, HASH_SIZE);
+
+    // Now use the library to compute the HMAC.
+    hash->resetHMAC(buffer, keyLen);
+    memset(buffer, 0xBA, sizeof(buffer));
+    hash->update(buffer, sizeof(buffer));
+    memset(buffer, (uint8_t)keyLen, keyLen);
+    hash->finalizeHMAC(buffer, keyLen, buffer, HASH_SIZE);
+
+    // Check the result.
+    if (!memcmp(result, buffer, HASH_SIZE))
+        Serial.println("Passed");
+    else
+        Serial.println("Failed");
+}
+
+void testHMAC(Hash *hash, const struct TestHashVector *test)
+{
+    uint8_t result[HASH_SIZE];
+
+    Serial.print(test->name);
+    Serial.print(" ... ");
+
+    hash->resetHMAC(test->key, strlen(test->key));
+    hash->update(test->data, strlen(test->data));
+    hash->finalizeHMAC(test->key, strlen(test->key), result, sizeof(result));
+
+    if (!memcmp(result, test->hash, HASH_SIZE))
+        Serial.println("Passed");
+    else
+        Serial.println("Failed");
+}
+
 void perfHash(Hash *hash)
 {
     unsigned long start;
@@ -133,6 +233,14 @@ void setup()
     Serial.println("Test Vectors:");
     testHash(&sha1, &testVectorSHA1_1);
     testHash(&sha1, &testVectorSHA1_2);
+    testHMAC(&sha1, &testVectorHMAC_SHA1_1);
+    testHMAC(&sha1, &testVectorHMAC_SHA1_2);
+    testHMAC(&sha1, (size_t)0);
+    testHMAC(&sha1, 1);
+    testHMAC(&sha1, HASH_SIZE);
+    testHMAC(&sha1, BLOCK_SIZE);
+    testHMAC(&sha1, BLOCK_SIZE + 1);
+    testHMAC(&sha1, sizeof(buffer));
 
     Serial.println();