/// <summary>
/// Register the standard hash algorithms.
/// </summary>
static MultiHash()
{
HashingAlgorithm.Register("sha1", 0x11, 20, SHA1.Create);
HashingAlgorithm.Register("sha2-256", 0x12, 32, SHA256.Create);
HashingAlgorithm.Register("sha2-512", 0x13, 64, SHA512.Create);
//HashingAlgorithm.Register("sha3-512", 0x14, 64, () => { return new SHA3.SHA3Managed(512); });
//HashingAlgorithm.Register("blake2b", 0x40, 64);
//HashingAlgorithm.Register("blake2s", 0x41, 32);
}
private void RaiseUnknownHashingAlgorithm(HashingAlgorithm algorithm)
{
//"Unknown hashing algorithm number 0x{0:x2}.", algorithm.Code
var handler = UnknownHashingAlgorithm;
if (handler != null)
{
var args = new UnknownHashingAlgorithmEventArgs {
Algorithm = algorithm
};
handler(this, args);
}
}
private void ValidateAlgorithm(byte fnCode, byte size)
{
Algorithm = HashingAlgorithm.Codes[fnCode];
if (Algorithm == null)
{
Algorithm = HashingAlgorithm.Register("custom-" + fnCode, fnCode, size);
RaiseUnknownHashingAlgorithm(Algorithm);
}
else if (size != Algorithm.DigestSize)
{
throw new InvalidDataException(string.Format("The digest size {0} is wrong for {1}; it should be {2}.", size, Algorithm.Name, Algorithm.DigestSize));
}
}
/// <summary>
/// Creates a new instance of the <see cref="MultiHash"/> class with the
/// specified <see cref="HashingAlgorithm">Algorithm name</see> and <see cref="Digest"/> value.
/// </summary>
/// <param name="algorithmName">
/// A valid IPFS hashing algorithm name, e.g. "sha2-256" or "sha2-512".
/// </param>
/// <param name="digest">
/// The digest value as a byte array.
/// </param>
public MultiHash(string algorithmName, byte[] digest)
{
Guard.NotNull(algorithmName, nameof(algorithmName));
Guard.NotNull(digest, nameof(digest));
HashingAlgorithm a;
if (!HashingAlgorithm.Names.TryGetValue(algorithmName, out a))
{
throw new ArgumentException(string.Format("The hashing algorithm '{0}' is unknown.", algorithmName));
}
Algorithm = a;
if (Algorithm.DigestSize != digest.Length)
{
throw new ArgumentException(string.Format("The digest size for '{0}' is {1} bytes, not {2}.", algorithmName, Algorithm.DigestSize, digest.Length));
}
Digest = digest;
}