AES Encryption/decryption
internal sealed class Cryptography
{
private static readonly byte[] Salt = Encoding.ASCII.GetBytes("X");
private static readonly string Sec = "Y"; // Can also be shared through functions!
public static string EncryptStringAES(string plainText)
{
if (string.IsNullOrEmpty(plainText))
throw new ArgumentNullException("plainText");
string outStr;
RijndaelManaged aesAlg = null;
try
{
var key = new Rfc2898DeriveBytes(Sec, Salt);
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
var encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
using (var msEncrypt = new MemoryStream())
{
msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0, sizeof(int));
msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (var swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(plainText);
}
}
outStr = Convert.ToBase64String(msEncrypt.ToArray());
}
}
finally
{
if (aesAlg != null)
{
aesAlg.Clear();
}
}
return outStr;
}
public static string DecryptStringAES(string cipherText)
{
if (string.IsNullOrEmpty(cipherText))
throw new ArgumentNullException("cipherText");
RijndaelManaged aesAlg = null;
string plaintext;
try
{
var key = new Rfc2898DeriveBytes(Sec, Salt);
byte[] bytes = Convert.FromBase64String(cipherText);
using (var msDecrypt = new MemoryStream(bytes))
{
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
aesAlg.IV = ReadByteArray(msDecrypt);
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
plaintext = srDecrypt.ReadToEnd();
}
}
}
finally
{
if (aesAlg != null)
aesAlg.Clear();
}
return plaintext;
}
private static byte[] ReadByteArray(Stream s)
{
var rawLength = new byte[sizeof(int)];
if (s.Read(rawLength, 0, rawLength.Length) != rawLength.Length)
{
throw new SystemException("Stream did not contain properly formatted byte array!");
}
var buffer = new byte[BitConverter.ToInt32(rawLength, 0)];
if (s.Read(buffer, 0, buffer.Length) != buffer.Length)
{
throw new SystemException("Did not read byte array properly!");
}
return buffer;
}
}