public static string EncodeCheck(VersionByte versionByte, byte[] data)
{
var bytes = new List <byte>
{
(byte)versionByte
};
bytes.AddRange(data);
var checksum = CalculateChecksum(bytes.ToArray());
bytes.AddRange(checksum);
return(Base32Encoding.ToString(bytes.ToArray(), options => options.OmitPadding = true));
}
private static byte[] CheckedBase32Decode(string encoded)
{
if (encoded.Length == 0)
{
throw new ArgumentException("Encoded string is empty");
}
foreach (var t in encoded)
{
if (t > 127)
{
throw new ArgumentException("Illegal characters in encoded string.");
}
}
return(Base32Encoding.ToBytes(encoded));
}
public static byte[] DecodeCheck(VersionByte versionByte, string encoded)
{
for (var i = 0; i < encoded.Length; i++)
{
if (encoded[i] > 127)
{
throw new ArgumentException("Illegal characters in encoded char array.");
}
}
var decoded = Base32Encoding.ToBytes(encoded);
var decodedVersionByte = decoded[0];
var payload = new byte[decoded.Length - 2];
Array.Copy(decoded, 0, payload, 0, payload.Length);
var data = new byte[payload.Length - 1];
Array.Copy(payload, 1, data, 0, data.Length);
var checksum = new byte[2];
Array.Copy(decoded, decoded.Length - 2, checksum, 0, checksum.Length);
if (decodedVersionByte != (byte)versionByte)
{
throw new FormatException("Version byte is invalid");
}
var expectedChecksum = CalculateChecksum(payload);
if (!expectedChecksum.SequenceEqual(checksum))
{
throw new FormatException("Checksum invalid");
}
return(data);
}