public static string HMAC(byte[] data, byte[] key)
{
// initialize key with zeros
//unsigned char usedKey[HashMethod::BlockSize] = {0};
uint numDataBytes = (uint)data.Length;
uint numKeyBytes = (uint)key.Length;
byte[] usedKey = new byte[BlockSize];
// adjust length of key: must contain exactly blockSize bytes
if (numKeyBytes <= BlockSize)
{
// copy key
//memcpy(usedKey, key, numKeyBytes);
usedKey = key;
Array.Resize(ref usedKey, (int)BlockSize);
}
else
{
// shorten key: usedKey = hashed(key)
HMAC_SHA256 keyHasher = new HMAC_SHA256();
keyHasher.add(key, numKeyBytes);
keyHasher.getHash(usedKey);
}
// create initial XOR padding
for (int i = 0; i < BlockSize; i++)
{
usedKey[i] ^= 0x36;
}
// inside = hash((usedKey ^ 0x36) + data)
byte[] inside = new byte[HashBytes];
HMAC_SHA256 insideHasher = new HMAC_SHA256();
insideHasher.add(usedKey, BlockSize);
insideHasher.add(data, numDataBytes);
inside = insideHasher.getHash(inside);
// undo usedKey's previous 0x36 XORing and apply a XOR by 0x5C
for (int i = 0; i < BlockSize; i++)
{
usedKey[i] ^= 0x5C ^ 0x36;
}
// hash((usedKey ^ 0x5C) + hash((usedKey ^ 0x36) + data))
HMAC_SHA256 finalHasher = new HMAC_SHA256();
finalHasher.add(usedKey, BlockSize);
finalHasher.add(inside, HashBytes);
byte[] buffer = new byte[32];
return(Convert.ToBase64String(finalHasher.getHash(buffer)));
}
public static string GetSHA256(string key, string message)
{
return(HMAC_SHA256.HMAC(Encoding.UTF8.GetBytes(message), Encoding.UTF8.GetBytes(key)));
//MacAlgorithmProvider sha256 = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA256");
//IBuffer contentBuffer = CryptographicBuffer.ConvertStringToBinary(message, BinaryStringEncoding.Utf8);
//IBuffer keyBuffer = CryptographicBuffer.ConvertStringToBinary(key, BinaryStringEncoding.Utf8);
//var signatureKey = sha256.CreateKey(keyBuffer);
//IBuffer digest = CryptographicEngine.Sign(signatureKey, contentBuffer);
//return CryptographicBuffer.EncodeToBase64String(digest);
}