public static byte[] Decrypt(byte[] key, byte[] initializationVector, byte[] cipher)
{
var decryptor = _cryptoProvider.CreateDecryptor(key, initializationVector);
using (var stream = new MemoryStream(cipher))
using (var cryptoStream = new CryptoStream(stream, decryptor, CryptoStreamMode.Read))
return(cryptoStream.ReadAll());
}
public static byte[] EncryptAes256(byte[] plaintext, byte[] key, PaddingMode padding = PaddingMode.None)
{
using (var aes = CreateAes256Cbc(key, padding))
using (var encryptor = aes.CreateEncryptor())
using (var stream = new MemoryStream(plaintext, false))
using (var cryptoStream = new CryptoStream(stream, encryptor, CryptoStreamMode.Read))
return(cryptoStream.ReadAll(256));
}
/// <summary>
/// Decrypts using AES/CBC/PKCS7 with an input byte array and key, using the random IV prepended using AES/ECB/None
/// </summary>
static byte[] SymmetricDecrypt(byte[] input, byte[] key, out byte[] iv)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricDecrypt used with non 32 byte key!");
using (var aes = Aes.Create())
{
aes.BlockSize = 128;
aes.KeySize = 256;
// first 16 bytes of input is the ECB encrypted IV
byte[] cryptedIv = new byte[16];
iv = new byte[cryptedIv.Length];
Array.Copy(input, 0, cryptedIv, 0, cryptedIv.Length);
// the rest is ciphertext
byte[] cipherText = new byte[input.Length - cryptedIv.Length];
Array.Copy(input, cryptedIv.Length, cipherText, 0, cipherText.Length);
// decrypt the IV using ECB
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.None;
using (var aesTransform = aes.CreateDecryptor(key, null))
{
iv = aesTransform.TransformFinalBlock(cryptedIv, 0, cryptedIv.Length);
}
// decrypt the remaining ciphertext in cbc with the decrypted IV
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateDecryptor(key, iv))
using (var ms = new MemoryStream(cipherText))
using (var cs = new CryptoStream(ms, aesTransform, CryptoStreamMode.Read))
{
// plaintext is never longer than ciphertext
byte[] plaintext = new byte[cipherText.Length];
int len = cs.ReadAll(plaintext);
byte[] output = new byte[len];
Array.Copy(plaintext, 0, output, 0, len);
return(output);
}
}
}
//Decryption
public static byte[] Decrypt(byte[] data, byte[] keySeed, byte[] ivSeed)
{
if (data == null)
{
throw new ArgumentNullException("data");
}
if (data.Length == 0)
{
return(new byte[0]);
}
if (keySeed == null)
{
throw new ArgumentNullException("keySeed");
}
if (keySeed.Length == 0)
{
throw new ArgumentException("keySeed length is zero!", "keySeed");
}
if (ivSeed == null)
{
throw new ArgumentNullException("IvSeed");
}
if (ivSeed.Length == 0)
{
throw new ArgumentException("IvSeed length is zero!", "IV");
}
byte[] Key = DeriveKeyFromSeed(keySeed);
byte[] IV = DeriveIVFromSeed(ivSeed);
byte[] decrypted;
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
using (MemoryStream msDecrypt = new MemoryStream(data))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
decrypted = csDecrypt.ReadAll();
}
}
}
return(decrypted);
}
public static byte[] Decrypt(Stream cipher, byte[] key, byte[] iv)
{
if (cipher == null || cipher.Length <= 0)
{
throw new ArgumentNullException(nameof(cipher));
}
if (key == null || key.Length <= 0)
{
throw new ArgumentNullException(nameof(key));
}
if (iv == null || iv.Length <= 0)
{
throw new ArgumentNullException(nameof(iv));
}
using (CryptoStream csDecrypt = DecryptStream(cipher, key, iv))
{
return(csDecrypt.ReadAll());
}
}
/// <summary>
/// Decrypts an input byte array using AES/CBC/PKCS7 with a given key and IV
/// </summary>
public static byte[] AESDecrypt(byte[] input, byte[] key, byte[] iv)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
if (iv == null)
{
throw new ArgumentNullException(nameof(iv));
}
using (var aes = Aes.Create())
{
aes.BlockSize = 128;
aes.KeySize = 128;
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
byte[] plainText = new byte[input.Length];
int outLen = 0;
using (var aesTransform = aes.CreateDecryptor(key, iv))
using (var ms = new MemoryStream(input))
using (var cs = new CryptoStream(ms, aesTransform, CryptoStreamMode.Read))
{
outLen = cs.ReadAll(plainText);
}
byte[] output = new byte[outLen];
Array.Copy(plainText, 0, output, 0, output.Length);
return(output);
}
}