Encrypt a String Using an AES Key

AES is a block cipher, therefore, you must send data to the server in chunks of 16 bytes. If String size is not multiple of 16, set to CBC mode. This will use padding to meet the 16-byte requirement. In the CBC mode, the AES algorithm requires a 16-byte initialization vector (IV).

To encrypt a string:

1. Create a NAE Session. Pass the NAE username, password, and property file path as arguments.

   NaeSession session = new NaeSession(user, passwd, propFilePath);
   

2. Create an NaeRijndaelKey object. Pass the NaeSession object and keyname as arguments.

   NaeRijndaelKey key = new NaeRijndaelKey(session, keyname);
   

3. Specify an IV, if necessary, by creating a new byte array.

   byte[] iv = { 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x30, 0x31,
   0x32, 0x33, 0x34, 0x35 };
   key.IV = iv;
   

4. Set key mode and padding.

   key.Padding = PaddingMode.PKCS7;
   key.Mode = CipherMode.CBC;
   

5. Encrypt the data.

   ICryptoTransform encryptor = key.CreateEncryptor();
   System.IO.MemoryStream memstr = new System.IO.MemoryStream();
   CryptoStream encrstr = new CryptoStream(memstr, encryptor, CryptoStreamMode.Write);
   encrstr.Write(inputBytes, 0, inputBytes.Length);
   encrstr.Close();
   encrBytes = memstr.ToArray();
   Console.WriteLine("Encrypted Data (B64 encoded): {0}", Convert.ToBase64String(encrBytes));