public static byte[] CTR128(byte[] block, byte[] key, byte[] ctr)
{
var aes = new AesCtr(ctr);
var output = new byte[block.Length];
aes.CreateDecryptor(key).TransformBlock(block, 0, block.Length, output, 0);
return(output);
}
public static void Test()
{
// Taken from http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf
// F.5.1 CTR-AES128.Encrypt and
// F.5.2 CTR-AES128.Decrypt
string[] keys = new[]
{
"2b7e151628aed2a6abf7158809cf4f3c",
"8e73b0f7da0e6452c810f32b809079e562f8ead2522c6b7b",
"603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4",
};
string[] plains = new[]
{
"6bc1bee22e409f96e93d7e117393172a",
"ae2d8a571e03ac9c9eb76fac45af8e51",
"30c81c46a35ce411e5fbc1191a0a52ef",
"f69f2445df4f9b17ad2b417be66c3710",
};
string[][] encrypteds = new[]
{
new[]
{
"874d6191b620e3261bef6864990db6ce",
"9806f66b7970fdff8617187bb9fffdff",
"5ae4df3edbd5d35e5b4f09020db03eab",
"1e031dda2fbe03d1792170a0f3009cee",
},
new[]
{
"1abc932417521ca24f2b0459fe7e6e0b",
"090339ec0aa6faefd5ccc2c6f4ce8e94",
"1e36b26bd1ebc670d1bd1d665620abf7",
"4f78a7f6d29809585a97daec58c6b050",
},
new[]
{
"601ec313775789a5b7a7f504bbf3d228",
"f443e3ca4d62b59aca84e990cacaf5c5",
"2b0930daa23de94ce87017ba2d84988d",
"dfc9c58db67aada613c2dd08457941a6",
},
};
for (int i = 0; i < keys.Length; i++)
{
var aes = new AesCtr();
aes.Key = GetBytes(keys[i]);
aes.IV = GetBytes("f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff");
Console.WriteLine("{0} bits", aes.KeySize);
{
Console.WriteLine("Encrypt");
ICryptoTransform encryptor = aes.CreateEncryptor();
var cipher = new byte[16];
for (int j = 0; j < plains.Length; j++)
{
byte[] plain = GetBytes(plains[j]);
encryptor.TransformBlock(plain, 0, plain.Length, cipher, 0);
string cipherHex = BitConverter.ToString(cipher).Replace("-", string.Empty).ToLowerInvariant();
if (cipherHex != encrypteds[i][j])
{
throw new Exception("Error encrypting " + j);
}
Console.WriteLine(cipherHex);
}
}
Console.WriteLine();
{
Console.WriteLine("Decrypt");
ICryptoTransform decryptor = aes.CreateDecryptor();
var plain = new byte[16];
for (int j = 0; j < encrypteds[i].Length; j++)
{
byte[] encrypted = GetBytes(encrypteds[i][j]);
decryptor.TransformBlock(encrypted, 0, encrypted.Length, plain, 0);
string plainHex = BitConverter.ToString(plain).Replace("-", string.Empty).ToLowerInvariant();
if (plainHex != plains[j])
{
throw new Exception("Error decrypting " + j);
}
Console.WriteLine(plainHex);
}
}
Console.WriteLine();
}
}
