Encryption and Decryption

 I am using the following functions for encryption and decryption of query strings from google search.
Public Shared Function Encrypt(ByVal strToEncrypt As String, ByVal strKey As String) As String
        Try
            Dim objDESCrypto As New TripleDESCryptoServiceProvider()
            Dim objHashMD5 As New MD5CryptoServiceProvider()
            Dim byteHash As Byte(), byteBuff As Byte()
            Dim strTempKey As String = strKey
            byteHash = objHashMD5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(strTempKey))
            objHashMD5 = Nothing
    ...