求在SQL Server 2000自定义的加密与解密函数及思路!

byte[] byKey = null; 
byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; 
byte[] inputByteArray = new Byte[inputString.Length];
try
{
byKey = System.Text.Encoding.UTF8.GetBytes(decryptKey.Substring(0,8));
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
inputByteArray = Convert.FromBase64String(inputString);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
System.Text.Encoding encoding = new System.Text.UTF8Encoding();
outString=encoding.GetString(ms.ToArray());
}
catch(System.Exception error)
{
this.errorMessage=error.Message;
outString="";
}
return outString;这是用C#写的解密算法,能否用SQL转下,求思路!