public static (HashingPreferences Prefs, byte[] Salt, byte[] Hash) DecodeHash(string encodedHash)
{
if (!encodedHash.StartsWith("$argon2id"))
{
throw new Exception("not an argon2id encoded hash");
}
var split = encodedHash.Split("$");
if (split.Length != 6)
{
throw new Exception("invalid hash format");
}
if (GetKvValue("v", split[2]) != ARGON2ID_VERSION)
{
throw new Exception("invalid hash version");
}
var prefs = new HashingPreferences();
var paramsSplit = split[3].Split(",");
prefs.MemorySize = GetKvValue("m", paramsSplit[0]);
prefs.Iterations = GetKvValue("t", paramsSplit[1]);
prefs.DegreeOfParallelism = GetKvValue("p", paramsSplit[2]);
var salt = Convert.FromBase64String(split[4]);
prefs.SaltLength = salt.Length;
var hash = Convert.FromBase64String(split[5]);
prefs.KeyLength = hash.Length;
return(prefs, salt, hash);
}
public async Task <bool> CompareEncodedHash(string password, string encodedHash)
{
if (password == null)
{
throw new ArgumentNullException(nameof(password));
}
if (password.Length == 0)
{
throw new ArgumentException("invalid length", nameof(password));
}
if (encodedHash == null)
{
throw new ArgumentNullException(nameof(encodedHash));
}
if (encodedHash.Length == 0)
{
throw new ArgumentException("invalid length", nameof(encodedHash));
}
var(prefs, salt, hash) = HashingPreferences.DecodeHash(encodedHash);
var hasher = prefs.MakeUnsaltedHasher(password);
hasher.Salt = salt;
var compHash = await hasher.GetBytesAsync(prefs.KeyLength);
return(compHash.SequenceEqual(hash));
}
