Encoding and Decoding using MD5 Alg

Encoding ascii = Encoding.ASCII;
Byte[] originalBytes;
Byte[] encodedBytes;
MD5 md5 = new MD5CryptoServiceProvider();
originalBytes = ascii.GetBytes(TextBox1.Text);
encodedBytes = md5.ComputeHash(originalBytes);
lblMD5.Text = ascii.GetString(encodedBytes);

Namepaces required
System.Text
System.Security.Cryptography
System.Data;