public static ArrayLease <byte> DecryptBytes(ArraySegment <byte> ciphertext, ArraySegment <byte> key, out int count)
{
// Blowfish processes things in blocks of 8, so
// it doesn't make sense to have a non-multiple
// of 8 length ciphertext (TODO: right?)
if ((ciphertext.Count & 7) != 0) // ciphertext.Count % 8 != 0
{
// TODO: Have a Strings.resx file for this
// Does project.json support that? / What benefits will that yield?
throw new ArgumentException(
message: "The length of the ciphertext needs to be divisible by 8.",
paramName: nameof(ciphertext));
}
// Since there's guaranteed to be no leftover,
// the count is just ciphertext.Count
count = ciphertext.Count;
var engine = new BlowfishEngine();
var keyParameter = new KeyParameter(key.Array, key.Offset, key.Count);
engine.Init(forEncryption: false, parameters: keyParameter);
var lease = ArrayPool <byte> .Shared.Lease(count);
try
{
var encryptBuffer = ciphertext.Array;
var decryptBuffer = lease.Array;
for (int i = 0; i < count; i += 8)
{
engine.ProcessBlock(encryptBuffer, ciphertext.Offset + i, decryptBuffer, i);
}
}
catch
{
lease.Dispose();
throw;
}
return(lease);
}
static byte[] decrypt(byte[] byteArray, BlowfishEngine bf)
{
int blockSize = 8;
List <byte> decrypted = new List <byte>();
for (int i = 0; i < byteArray.Length; i = i + blockSize)
{
byte[] blockBytes = new byte[blockSize];
byte[] outBytes = new byte[blockSize];
for (int j = 0; j < blockSize; j++)
{
blockBytes[j] = byteArray[i + j];
}
bf.ProcessBlock(blockBytes, 0, outBytes, 0);
decrypted.AddRange(outBytes);
}
unpad(decrypted);
return(decrypted.ToArray());
}
/// <summary>
/// Encrypted the data.
/// </summary>
/// <param name="data">The data to encrypted.</param>
/// <param name="passphrase">The passphrase key used to mask the data.</param>
/// <returns>The encrypted data.</returns>
public byte[] Encrypt(byte[] data, string passphrase)
{
// Create the key parameters.
byte[] key = Encoding.Default.GetBytes(passphrase);
Key.Crypto.Parameters.KeyParameter keyParameter = new KeyParameter(key);
// Initialise the cryptography engine.
Key.Crypto.Engines.BlowfishEngine blowfish = new BlowfishEngine();
blowfish.Init(true, keyParameter);
int dataLength = data.Length;
int blockSize = blowfish.GetBlockSize();
int modBlockSize = dataLength % blockSize;
int blockCount = dataLength / blockSize;
// If there is a remained then add en extra block count.
if ((modBlockSize) > 0)
{
// Add one extra block.
blockCount++;
}
// Encrypted data store.
byte[] encryptedData = new byte[blockCount * blockSize];
byte[] decryptedData = new byte[blockCount * blockSize];
// Copy the decrypted data.
for (int j = 0; j < dataLength; j++)
{
// Assign the data.
decryptedData[j] = data[j];
}
// For each block size in the the data.
for (int i = 0; i < blockCount; i++)
{
// Encrypt the block.
blowfish.ProcessBlock(decryptedData, (i * blockSize), encryptedData, (i * blockSize));
}
// Return the encrypted data.
return(encryptedData);
}
private void decrypt(byte[] value, BlowfishEngine bf)
{
int blockSize = bf.GetBlockSize();
byte[] vector = new byte[blockSize];
for (int i = 0; i < blockSize; i++)
{
vector[i] = 0;
}
for (int i = 0; i < value.Length; i += blockSize)
{
byte[] tmp = new byte[blockSize];
bf.ProcessBlock(vector, 0, tmp, 0);
int chunk = Math.Min(blockSize, value.Length - i);
for (int j = 0; j < chunk; j++)
{
vector[j] = value[i + j];
value[(i + j)] = (byte)(value[(i + j)] ^ tmp[j]);
}
;
}
;
}
private static byte[] ProcessData(byte[] data, byte[] key, bool forEncryption)
{
byte[] input = data;
bool paddingRequired = data.Length % BlockSize > 0;
if (paddingRequired)
{
input = new byte[data.Length + BlockSize - data.Length % BlockSize];
Buffer.BlockCopy(data, 0, input, 0, data.Length);
}
byte[] output = new byte[input.Length];
BlowfishEngine engine = new BlowfishEngine();
engine.Init(forEncryption, key);
int offset = 0;
while (offset < input.Length)
{
engine.ProcessBlock(input, offset, output, offset);
offset += BlockSize;
}
if (paddingRequired)
{
byte[] unpaddedOutput = new byte[data.Length];
Buffer.BlockCopy(output, 0, unpaddedOutput, 0, unpaddedOutput.Length);
return(unpaddedOutput);
}
return(output);
}
public static ArrayLease <byte> EncryptBytes(ArraySegment <byte> plaintext, ArraySegment <byte> key, out int count)
{
// Blowfish encrypts 8 bytes at a time
int leftover = plaintext.Count & 7;
count = (plaintext.Count + 7) & ~7; // branchless version of: n - (n % 8) + 8
// if there's leftover we'll need another extra 8 bytes to hold the input
// note that this should not be part of the outputted array,
// so store it in a new variable
int capacity = count + ((leftover + 7) & ~7);
Debug.Assert(leftover == 0 ^ capacity != plaintext.Count);
var engine = new BlowfishEngine();
var keyParameter = new KeyParameter(key.Array, key.Offset, key.Count);
engine.Init(forEncryption: true, parameters: keyParameter);
var lease = ArrayPool <byte> .Shared.Lease(capacity);
try
{
int i = plaintext.Offset;
int j = 0;
byte[] input = plaintext.Array;
byte[] output = lease.Array;
// Process each block of bytes
while (i + 7 < plaintext.Count)
{
engine.ProcessBlock(input, i, output, j);
i += 8;
j += 8;
}
Debug.Assert(
i + leftover == plaintext.Count &&
leftover >= 0 &&
leftover < 8);
if (leftover != 0)
{
// Handle the leftover input bytes
Debug.Assert(
count > plaintext.Count &&
(count % 8) == 0 &&
capacity == count + 8);
// Copy over the remaining input data to the end of the output array
int inputIndex = i, outputIndex = j + 8;
while (inputIndex < plaintext.Count)
{
output[outputIndex++] = input[inputIndex++];
}
// Since this is a rented array, clear any extraneous data at the end
// Use a regular while loop, since it's less than 8 bytes
Debug.Assert(
outputIndex <= capacity &&
capacity - outputIndex < 8);
while (outputIndex < capacity)
{
output[outputIndex++] = 0;
}
engine.ProcessBlock(output, j + 8, output, j);
}
}
catch
{
lease.Dispose();
throw;
}
return(lease);
}