public static byte[] Decrypt36(string value)
{
//Split 4 part Id into 4 ulong
string[] _ids = value.Split('-');
if (_ids.Length != 4)
{
throw new ArgumentException("Wrong value!");
}
//Combine 4 part Id into one byte array
byte[] _value = new byte[16];
Buffer.BlockCopy(BitConverter.GetBytes(BASE36.Decode(_ids[0])), 0, _value, 0, 8);
Buffer.BlockCopy(BitConverter.GetBytes(BASE36.Decode(_ids[1])), 0, _value, 8, 8);
Buffer.BlockCopy(BitConverter.GetBytes(BASE36.Decode(_ids[2])), 0, _value, 16, 8);
Buffer.BlockCopy(BitConverter.GetBytes(BASE36.Decode(_ids[3])), 0, _value, 24, 8);
return(_value);
}
public static string Encrypt36(string value)
{
//Combine the IDs and get bytes
byte[] _byteIds = Encoding.UTF8.GetBytes(value);
//Use MD5 to get the fixed length checksum of the ID string
MD5CryptoServiceProvider _md5 = new MD5CryptoServiceProvider();
byte[] _checksum = _md5.ComputeHash(_byteIds);
//Convert checksum into 4 ulong parts and use BASE36 to encode both
string _part1Id = BASE36.Encode(BitConverter.ToUInt32(_checksum, 0));
string _part2Id = BASE36.Encode(BitConverter.ToUInt32(_checksum, 4));
string _part3Id = BASE36.Encode(BitConverter.ToUInt32(_checksum, 8));
string _part4Id = BASE36.Encode(BitConverter.ToUInt32(_checksum, 12));
//Concat these 4 part into one string
return(string.Format("{0}-{1}-{2}-{3}", _part1Id, _part2Id, _part3Id, _part4Id));
}
