Encryption and Decryption

Question

I have to encrypt an id from sql but encrypted key should be short like u00b1 also to decrypt it. For Ex. http://localhost/Survey/Survey.aspx?id=%u00b1

Ananth G · Answer

Encryption Sometimes we want to encrypt the values that time we use MD5 Encryption and Decryption Here i give the code for Encryption and Decryption. passPhrase ,saltValue ,initVector this variables are the key for Encryption and Decryption public static string passPhrase = "YOUR KEY1"; public static string saltValue = "YOUR KE2"; public static string initVector = "YOUR KE3"; public static string FunForEncrypt(string objText) { int keySize = 256; int passwordIterations = 03; string hashAlgorithm = "MD5"; byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); byte[] plainTextBytes = Encoding.UTF8.GetBytes(objText); PasswordDeriveBytes password = new PasswordDeriveBytes ( passPhrase, saltValueBytes, hashAlgorithm, passwordIterations ); byte[] keyBytes = password.GetBytes(keySize / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform encryptor = symmetricKey.CreateEncryptor ( keyBytes, initVectorBytes ); MemoryStream memoryStream = new MemoryStream(); CryptoStream cryptoStream = new CryptoStream ( memoryStream, encryptor, CryptoStreamMode.Write ); cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length); cryptoStream.FlushFinalBlock(); byte[] cipherTextBytes = memoryStream.ToArray(); memoryStream.Close(); cryptoStream.Close(); string cipherText = Convert.ToBase64String(cipherTextBytes); cipherText = HttpUtility.UrlEncode(cipherText); return cipherText; } Decryption : this below code used to Decrypt the text public static string FunForDecrypt(string cipherText) { string plainText = ""; int keySize = 256; int passwordIterations = 03; string hashAlgorithm = "MD5"; try { cipherText = HttpUtility.UrlDecode(cipherText); byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector); byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue); byte[] cipherTextBytes = Convert.FromBase64String(cipherText); PasswordDeriveBytes password = new PasswordDeriveBytes ( passPhrase, saltValueBytes, hashAlgorithm, passwordIterations ); byte[] keyBytes = password.GetBytes(keySize / 8); RijndaelManaged symmetricKey = new RijndaelManaged(); symmetricKey.Mode = CipherMode.CBC; ICryptoTransform decryptor = symmetricKey.CreateDecryptor ( keyBytes, initVectorBytes ); MemoryStream memoryStream = new MemoryStream(cipherTextBytes); CryptoStream cryptoStream = new CryptoStream ( memoryStream, decryptor, CryptoStreamMode.Read ); byte[] plainTextBytes = new byte[cipherTextBytes.Length]; int decryptedByteCount = cryptoStream.Read ( plainTextBytes, 0, plainTextBytes.Length ); memoryStream.Close(); cryptoStream.Close(); plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount); } catch (Exception ex) { plainText = ""; } return plainText; }

Bikesh Srivastava · Answer

See this code to encrypt and decrypt username and password. I have done already in my application ,its working fine . privatestringEncrypt(stringclearText) { stringEncryptionKey= "MAKV2SPBNI99212" ; byte []clearBytes=Encoding.Unicode.GetBytes(clearText); using (Aesencryptor=Aes.Create()) { Rfc2898DeriveBytespdb=newRfc2898DeriveBytes(EncryptionKey,newbyte[]{0x49,0x76,0x61,0x6e,0x20,0x4d,0x65,0x64,0x76,0x65,0x64,0x65,0x76}); encryptor.Key=pdb.GetBytes(32); encryptor.IV=pdb.GetBytes(16); using (MemoryStreamms=newMemoryStream()) { using (CryptoStreamcs=newCryptoStream(ms,encryptor.CreateEncryptor(),CryptoStreamMode.Write)) { cs.Write(clearBytes,0,clearBytes.Length); cs.Close(); } clearText=Convert.ToBase64String(ms.ToArray()); } } returnclearText; } privatestringDecrypt(stringcipherText) { stringEncryptionKey= "MAKV2SPBNI99212" ; byte []cipherBytes=Convert.FromBase64String(cipherText); using (Aesencryptor=Aes.Create()) { Rfc2898DeriveBytespdb=newRfc2898DeriveBytes(EncryptionKey,newbyte[]{0x49,0x76,0x61,0x6e,0x20,0x4d,0x65,0x64,0x76,0x65,0x64,0x65,0x76}); encryptor.Key=pdb.GetBytes(32); encryptor.IV=pdb.GetBytes(16); using (MemoryStreamms=newMemoryStream()) { using (CryptoStreamcs=newCryptoStream(ms,encryptor.CreateDecryptor(),CryptoStreamMode.Write)) { cs.Write(cipherBytes,0,cipherBytes.Length); cs.Close(); } cipherText=Encoding.Unicode.GetString(ms.ToArray()); } } returncipherText; } mark as answer if resolve your problem.

Vinay Singh · Answer

Hi Saurabh, It the same thin which i have posted. It's a sql query which perform encryption and decryption in sql only. Please check the query and it's output posted by me.

Vinay Singh · Answer

Hi you can user encryption and decryption in sql as shown : declare @encrypt varbinary(200) select @encrypt = EncryptByPassPhrase( 'key' , 'abc' ) select @encrypt select convert(varchar(100),DecryptByPassPhrase( 'key' , @encrypt )) Output --------------------------------------------------------------------------- 0x010000009912C2B009EEAC5B7F2A9020D433D3EAFA026004ADD5AAB4 (1 row(s) affected) --------------------------------------------------------------------------- abc (1 row(s) affected) for detail check the links http://www.codeproject.com/Questions/376609/How-to-encrypt-decrypt-string-in-sql-server https://msdn.microsoft.com/en-us/library/ms174361.aspx http://sqlmag.com/t-sql/simple-string-encryption-and-decryption

Saurabh Singh · Answer

Thanks for your reply but I have to encrypt it in SQL Server.

Avikshith Aradhya · Answer

You can refer below link for information on how to Encrypt query string in URL, http://www.c-sharpcorner.com/UploadFile/cd7c2e/global-query-string-encryption-in-C-Sharp/

Encryption and Decryption

Answers (6)