PKCS7 padding is invalid and cannot be removed

Question

Hi All, I get this Cryptography exception while decrypting a querystring. Any Help in this will be appreciated. Thanks Here is my code for encryption/decryption. using System; using System.IO; using System.Text; using System.Security.Cryptography; namespace lweb { ///

/// Summary description for Encryption. ///

public class Encryption { byte [] key; byte [] IV; byte [] inputByteArray; RijndaelManaged myR = new RijndaelManaged(); public Encryption() { myR.GenerateKey(); myR.GenerateIV(); key = myR.Key; IV = myR.IV; } public string Decrypt(string stringToDecrypt) { inputByteArray = new byte[stringToDecrypt.Length]; ICryptoTransform decryptor = myR.CreateDecryptor(key, IV); try { inputByteArray = Convert.FromBase64String(stringToDecrypt); MemoryStream ms = new MemoryStream(); CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Write); cs.Write(inputByteArray, 0, inputByteArray.Length); cs.FlushFinalBlock(); ASCIIEncoding encoding = new ASCIIEncoding(); return encoding.GetString(ms.ToArray()); } catch(System.Exception ex) { throw ex; } } public string Encrypt(string stringToEncrypt) { inputByteArray = Encoding.UTF8.GetBytes(stringToEncrypt); ICryptoTransform encryptor = myR.CreateEncryptor(key, IV); try { MemoryStream ms = new MemoryStream(); CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write); cs.Write(inputByteArray, 0, inputByteArray.Length); cs.FlushFinalBlock(); return Convert.ToBase64String(ms.ToArray()); } catch(System.Exception ex) { throw ex; } } } } I am using this for Encryption, which works fine string userModURL = "updateProfile.aspx?FN="; string test = oES.Encrypt(fn.Text.ToString()); userModURL = userModURL + test; Decryption which doesnt works string ff = Request.QueryString["FN"]; string dd = ff.Replace(" ", "+"); string ee = oES.Decrypt(dd); The decrypt page works fine within the same page, i.e., if i encrypt and decrypt the strings on the same page.