public static byte[] EncryptProfileFor(string email)
{
var profile = ProfileFor(email);
var bytes = System.Text.Encoding.ASCII.GetBytes(profile);
var padded = PaddingUtil.Pad(bytes, BlockSizeBytes);
return(AesEcb.Encrypt(Key, padded));
}
public static Dictionary <string, string> DecryptProfile(byte[] encrypted)
{
var decrypted = AesEcb.Decrypt(Key, encrypted);
var encoded = PaddingUtil.RemovePad(decrypted);
var decoded = KvpParser.Decode(System.Text.Encoding.ASCII.GetString(encoded));
return(decoded);
}
private static byte[] EncryptionOracle(byte[] data)
{
var combined = new List <byte>();
combined.AddRange(data);
combined.AddRange(Convert.FromBase64String(EncodedSuffix));
var padded = PaddingUtil.Pad(combined.ToArray(), BlockSizeBytes);
return(AesEcb.Encrypt(Key, padded));
}
public static bool ConfirmEcbMode(int blockSize)
{
var b = SecureRng.GenerateRandomBytes(blockSize);
var duplicateBlocks = new List <byte>();
duplicateBlocks.AddRange(b);
duplicateBlocks.AddRange(b);
var encrypted = EncryptionOracle(duplicateBlocks.ToArray());
return(AesEcb.IsEcbEncrypted(encrypted, blockSize));
}
private static byte[] EncryptionOracle(byte[] data)
{
if (_randomPrefix == null || _randomPrefix.Length == 0)
{
var r = new Random();
var prefixLength = r.Next(1, MaxPrefixLength + 1);
_randomPrefix = SecureRng.GenerateRandomBytes(prefixLength);
}
var combined = new List <byte>();
combined.AddRange(_randomPrefix);
combined.AddRange(data);
combined.AddRange(Convert.FromBase64String(EncodedSuffix));
var padded = PaddingUtil.Pad(combined.ToArray(), BlockSizeBytes);
return(AesEcb.Encrypt(Key, padded));
}
public static byte[] Encrypt(byte[] key, byte[] nonce, byte[] data)
{
ulong counter = 0;
var keyStream = new byte[BlockSizeBytes];
var blocks = data.Chunks(BlockSizeBytes);
var xord = new List <byte>(data.Length);
foreach (var block in blocks)
{
var counterBytes = BitConverter.GetBytes(counter);
Array.Copy(nonce, keyStream, nonce.Length);
Array.Copy(counterBytes, 0, keyStream, nonce.Length, counterBytes.Length);
var blockKey = AesEcb.Encrypt(key, keyStream);
xord.AddRange(XorUtil.Xor(block, blockKey));
counter++;
}
return(xord.ToArray());
}
public static byte[] Decrypt(byte[] key, byte[] iv, byte[] data, bool removePadding = true)
{
var blocks = data.Chunks(BlockSizeBytes);
var clearText = new byte[data.Length];
int index = 0;
var previousBlock = iv;
foreach (var block in blocks)
{
var blockArray = block.ToArray();
var decrypted = AesEcb.Decrypt(key, blockArray);
var xord = XorUtil.Xor(decrypted, previousBlock);
Array.Copy(xord, 0, clearText, index, BlockSizeBytes);
previousBlock = blockArray;
index += BlockSizeBytes;
}
if (removePadding)
{
return(PaddingUtil.RemovePad(clearText));
}
return(clearText);
}
public static byte[] Encrypt(byte[] key, byte[] iv, byte[] data)
{
int paddingLength = BlockSizeBytes - (data.Length % BlockSizeBytes);
paddingLength = paddingLength == 0 ? BlockSizeBytes : paddingLength;
int cipherTextLength = data.Length + paddingLength;
var cipherText = new byte[cipherTextLength];
var paddedData = PaddingUtil.Pad(data, BlockSizeBytes);
var blocks = paddedData.Chunks(BlockSizeBytes);
int index = 0;
var previousBlock = iv;
foreach (var block in blocks)
{
var xord = XorUtil.Xor(block.ToArray(), previousBlock);
var encrypted = AesEcb.Encrypt(key, xord);
Array.Copy(encrypted, 0, cipherText, index, BlockSizeBytes);
previousBlock = encrypted;
index += BlockSizeBytes;
}
return(cipherText);
}
public static CipherMode EncryptEcbOrCbc(byte[] data, out CipherMode actualMode)
{
actualMode = Rand.Next(0, 2) == 0 ? CipherMode.ECB : CipherMode.CBC;
var key = SecureRng.GenerateRandomBytes(KeySizeBytes);
// Add prefix and suffix to data
data = TransformData(data);
byte[] encrypted;
if (actualMode == CipherMode.ECB)
{
var padded = PaddingUtil.Pad(data, BlockSizeBytes);
encrypted = AesEcb.Encrypt(key, padded);
}
else
{
var iv = SecureRng.GenerateRandomBytes(BlockSizeBytes);
encrypted = AesCbc.Encrypt(key, iv, data);
}
var guessedMode = AesEcb.IsEcbEncrypted(encrypted, BlockSizeBytes)
? CipherMode.ECB
: CipherMode.CBC;
return(guessedMode);
}
