/// <summary>Hashes a message, with an optional key, using the BLAKE2b primitive.</summary>
/// <param name="message">The message to be hashed.</param>
/// <param name="key">The key; may be null, otherwise between 16 and 64 bytes.</param>
/// <param name="bytes">The size (in bytes) of the desired result.</param>
/// <returns>Returns a byte array.</returns>
/// <exception cref="KeyOutOfRangeException"></exception>
/// <exception cref="BytesOutOfRangeException"></exception>
public static byte[] Hash(byte[] message, byte[] key, int bytes)
{
//validate the length of the key
int keyLength;
if (key != null)
{
if (key.Length > KEY_BYTES_MAX || key.Length < KEY_BYTES_MIN)
{
throw new KeyOutOfRangeException(string.Format("key must be between {0} and {1} bytes in length.",
KEY_BYTES_MIN, KEY_BYTES_MAX));
}
keyLength = key.Length;
}
else
{
key = new byte[0];
keyLength = 0;
}
//validate output length
if (bytes > BYTES_MAX || bytes < BYTES_MIN)
{
throw new BytesOutOfRangeException("bytes", bytes,
string.Format("bytes must be between {0} and {1} bytes in length.", BYTES_MIN, BYTES_MAX));
}
var buffer = new byte[bytes];
SodiumLibrary.crypto_generichash(buffer, buffer.Length, message, message.Length, key, keyLength);
return(buffer);
}
