/// <summary>
/// Get a stream as the result of the specified stream being compressed using the specified method. Optionally specify a length
/// for the number of bytes to read.
/// </summary>
public static MemoryStream Compress(System.Net.DecompressionMethods method, CompressionLevel level, Stream source, int length = -1)
{
// create a new memory stream to receive the compressed stream
MemoryStream memStream = new MemoryStream(Global.BufferSizeLocal);
// resolve the compression stream
Stream compressionStream;
switch (method)
{
case System.Net.DecompressionMethods.Deflate:
compressionStream = new GZipStream(memStream, level, true);
break;
case System.Net.DecompressionMethods.GZip:
compressionStream = new DeflateStream(memStream, level, true);
break;
default:
// no compression - return uncompressed
source.CopyTo(memStream);
return(memStream);
}
// was the length specifed?
if (length == -1)
{
// no, write the buffer to the compression
source.CopyTo(compressionStream, Global.BufferSizeLocal);
}
else
{
// yes, create a buffer for the copy
byte[] buffer = BufferCache.Get();
int count = Global.BufferSizeLocal;
// while the buffer is filled by reading from the stream
while (count == Global.BufferSizeLocal)
{
// read from the stream
count = length < Global.BufferSizeLocal ?
source.Read(buffer, 0, length) :
source.Read(buffer, 0, Global.BufferSizeLocal);
// write to the compression stream
compressionStream.Write(buffer, 0, count);
// decrement the remaining bytes
length -= count;
}
BufferCache.Set(buffer);
}
// close the compression stream
compressionStream.Close();
// return the memory stream
return(memStream);
}
/// <summary>
/// Inner method compress stream method.
/// </summary>
private static void Compress(IRun callback, Stream result, Stream destination, Stream source,
int length, bool dispose)
{
// reset the buffer
byte[] buffer = BufferCache.Get();
int count;
if (length == -1)
{
// read from the stream
count = source.Read(buffer, 0, Global.BufferSizeLocal);
}
else
{
// read from the stream
count = length < Global.BufferSizeLocal ?
source.Read(buffer, 0, length) :
source.Read(buffer, 0, Global.BufferSizeLocal);
// decrement the remaining bytes
length -= count;
}
// write to the compression stream
destination.Write(buffer, 0, count);
// reset the buffer
BufferCache.Set(buffer);
// has the compression been completed?
if (count == Global.BufferSizeLocal)
{
// no, run a new compression iteration
ManagerUpdate.Control.AddSingle(Compress, callback, result, destination, source, length, dispose);
}
else
{
// yes, dispose of the compression stream
destination.Dispose();
// should the source be disposed? yes
if (dispose)
{
source.Dispose();
}
// reset the memory stream position
result.Position = 0L;
// yes, run the callback
callback.Run();
}
}
/// <summary>
/// Continuing compute of a hash of the specified stream.
/// </summary>
protected void ComputeHashInner(Stream stream, IAction <byte[]> onComplete, byte[] buffer, int index)
{
if (buffer == null)
{
buffer = BufferCache.Get();
index = 0;
}
int count = stream.Read(buffer, index, Global.BufferSizeLocal);
bool last = count != Global.BufferSizeLocal;
_h1 = _seed;
_length = 0;
// read 128 bits, 16 bytes, 2 longs in eacy cycle
while (index + 16 <= count)
{
ulong k1 = GetUInt64(buffer, index);
ulong k2 = GetUInt64(buffer, index + 8);
_length += ReadSize;
MixBody(k1, k2);
index += 16;
}
if (index + 16 == count)
{
BufferCache.Set(buffer);
buffer = null;
}
else
{
if (last)
{
// if the input MOD 16 != 0
if (index < count)
{
ProcessBytesRemaining(buffer, count - index, index);
}
onComplete.ArgA = Hash;
onComplete.Run();
return;
}
Micron.CopyMemory(buffer, index, buffer, 0, count - index);
index -= count;
}
ManagerUpdate.Control.AddSingle(ComputeHashInner, stream, onComplete, buffer, index);
}
/// <summary>
/// Compress the specified byte buffer.
/// </summary>
public static Stream Decompress(System.Net.DecompressionMethods method, Stream source, ref int count)
{
// create a new memory stream to receive the compressed stream
MemoryStream memStream = new MemoryStream();
// resolve the compression stream
Stream compressionStream;
switch (method)
{
case System.Net.DecompressionMethods.Deflate:
compressionStream = new DeflateStream(memStream, CompressionMode.Decompress, true);
break;
case System.Net.DecompressionMethods.GZip:
compressionStream = new GZipStream(memStream, CompressionMode.Decompress, true);
break;
default:
// no compression - return uncompressed
return(source);
}
// write the buffer to the compression
var buffer = BufferCache.Get();
int bufferCount = Global.BufferSizeLocal;
while (bufferCount == Global.BufferSizeLocal)
{
bufferCount = source.Read(buffer, 0, count > Global.BufferSizeLocal ? Global.BufferSizeLocal : count);
count -= bufferCount;
compressionStream.Write(buffer, 0, bufferCount);
}
// pass the buffer back to the cache
BufferCache.Set(buffer);
// close the stream
compressionStream.Dispose();
// get the count
memStream.Position = 0L;
count = (int)memStream.Length;
// get the bytes from the memory stream
return(memStream);
}
/// <summary>
/// Copy the content of a stream to another over a series of async tasks.
/// </summary>
public static void BufferedCopy(this Stream inStream, Stream outStream, IAction onComplete = null)
{
var buffer = BufferCache.Get();
int count = inStream.Read(buffer, 0, Global.BufferSizeLocal);
if (count == 0)
{
outStream.Flush();
BufferCache.Set(buffer);
if (onComplete != null)
{
onComplete.Run();
}
}
else
{
outStream.Write(buffer, 0, count);
BufferCache.Set(buffer);
ManagerUpdate.Control.AddSingle(BufferedCopy, inStream, outStream, onComplete);
}
}
/// <summary>
/// Decrypt with password. The stream must be navigatable.
/// </summary>
public static Stream DecryptWithPassword(Stream stream, string password, int nonSecretPayloadLength = 0)
{
const int ivLength = BlockBitSize / 8;
var cryptSalt = new byte[SaltBitSize];
var authSalt = new byte[SaltBitSize];
var streamStartPosition = stream.Position;
// grab Salt from Non-Secret Payload
if (nonSecretPayloadLength != 0)
{
stream.Position = streamStartPosition + nonSecretPayloadLength;
}
stream.Read(cryptSalt, 0, SaltBitSize);
stream.Read(authSalt, 0, SaltBitSize);
// grab IV from message
var iv = new byte[ivLength];
stream.Read(iv, 0, ivLength);
byte[] cryptKey;
byte[] authKey;
// generate crypt key
using (var generator = new Rfc2898DeriveBytes(password, cryptSalt, Iterations)) {
cryptKey = generator.GetBytes(KeyBitSize);
}
// generate auth key
using (var generator = new Rfc2898DeriveBytes(password, authSalt, Iterations)) {
authKey = generator.GetBytes(KeyBitSize);
}
using (var hmac = new HMACSHA256(authKey)) {
int sentTagLength = hmac.HashSize / 8;
// if message length is to small just return null
if (stream.Length - streamStartPosition < sentTagLength + nonSecretPayloadLength + ivLength)
{
throw new CryptographicException("Insufficient bytes in stream.");
}
// get the number of encrypted bytes that constitute the message
int count = (int)(stream.Length -
streamStartPosition -
sentTagLength -
nonSecretPayloadLength -
ivLength -
SaltBitSize - SaltBitSize);
byte[] tagContent = BufferCache.Get(count);
// read the bytes required for the tag hash
count = stream.Read(tagContent, 0, count);
// calculate the tag hash
byte[] calcTag = hmac.ComputeHash(tagContent, 0, count);
// read sent tag
stream.Read(tagContent, 0, sentTagLength);
// compare tag with constant time comparison
var compare = 0;
for (var i = 0; i < sentTagLength; ++i)
{
compare |= tagContent[i] ^ calcTag[i];
}
BufferCache.Set(tagContent);
// if message doesn't authenticate, throw
if (compare != 0)
{
throw new CryptographicException("Data hash was not correct.");
}
using (var aes = new AesManaged {
Key = cryptKey,
IV = iv,
BlockSize = BlockBitSize,
Mode = CipherMode.CBC,
Padding = PaddingMode.Zeros
}) {
// create a memory stream for the decrypted bytes
var decrypted = new MemoryStream();
using (var decrypter = aes.CreateDecryptor()) {
var decrypterStream = new CryptoStream(decrypted, decrypter, CryptoStreamMode.Write);
byte[] buffer = BufferCache.Get();
// move to the start of the encrypted data
stream.Position = streamStartPosition +
nonSecretPayloadLength +
SaltBitSize + SaltBitSize +
ivLength;
// determine the bytes to be written to the decrypter stream
int remaining = (int)(stream.Length - stream.Position - sentTagLength);
// read the first buffer from the stream
count = stream.Read(buffer, 0, remaining > Global.BufferSizeLocal ? Global.BufferSizeLocal : remaining);
// while the buffer is full
while (count == Global.BufferSizeLocal)
{
// decrement the remaining bytes
remaining -= count;
// write the buffer
decrypterStream.Write(buffer, 0, count);
// read a new buffer
count = stream.Read(buffer, 0, Global.BufferSizeLocal);
}
// if the stream ended prematurely, throw
if (count != remaining)
{
throw new EndOfStreamException();
}
// write final buffer
decrypterStream.Write(buffer, 0, count);
BufferCache.Set(buffer);
// flush the decryption stream
decrypterStream.FlushFinalBlock();
// set the decrpted memory stream position
decrypted.Position = 0;
// return the decrypted stream
return(decrypted);
}
}
}
}
/// <summary>
/// Encrypt bytes from the stream using a string password.
/// </summary>
public static MemoryStream EncryptWithPassword(Stream stream, string password, byte[] nonSecretPayload = null)
{
byte[] payload;
int payloadIndex;
if (nonSecretPayload == null)
{
payload = BufferCache.Get(SaltBitSize * 2);
payloadIndex = 0;
}
else
{
payload = BufferCache.Get((SaltBitSize * 2) + nonSecretPayload.Length);
Array.Copy(nonSecretPayload, payload, nonSecretPayload.Length);
payloadIndex = nonSecretPayload.Length;
}
byte[] cryptKey;
byte[] authKey;
//Use Random Salt to prevent pre-generated weak password attacks.
using (var generator = new Rfc2898DeriveBytes(password, SaltBitSize, Iterations)) {
var salt = generator.Salt;
// generate the cryptography key
cryptKey = generator.GetBytes(KeyBitSize);
// copy the salt
Array.Copy(salt, 0, payload, payloadIndex, salt.Length);
payloadIndex += salt.Length;
}
//Deriving separate key, might be less efficient than using HKDF,
//but now compatible with RNEncryptor which had a very similar wireformat and requires less code than HKDF.
using (var generator = new Rfc2898DeriveBytes(password, SaltBitSize, Iterations)) {
var salt = generator.Salt;
// generate the auth key
authKey = generator.GetBytes(KeyBitSize);
// create the rest of the non-secret payload
Array.Copy(salt, 0, payload, payloadIndex, salt.Length);
payloadIndex += salt.Length;
}
byte[] iv;
byte[] buffer = BufferCache.Get();
using (var aes = new AesManaged {
Key = cryptKey,
BlockSize = BlockBitSize,
Mode = CipherMode.CBC,
Padding = PaddingMode.Zeros
}) {
// use random IV
aes.GenerateIV();
iv = aes.IV;
using (var encrypter = aes.CreateEncryptor())
using (var cipherStream = new MemoryStream())
using (var cryptoStream = new CryptoStream(cipherStream, encrypter, CryptoStreamMode.Write)) {
// read from the stream
int count = stream.Read(buffer, 0, Global.BufferSizeLocal);
// while the buffer is filled
while (count == Global.BufferSizeLocal)
{
// write to the crypto stream
cryptoStream.Write(buffer, 0, count);
// read from the stream
count = stream.Read(buffer, 0, Global.BufferSizeLocal);
}
// write the final buffer
cryptoStream.Write(buffer, 0, count);
// flush the encryped stream
cryptoStream.Flush();
cipherStream.Position = 0;
// assemble encrypted message and add authentication
var encryptedStream = new MemoryStream();
// prepend payload
encryptedStream.Write(payload, 0, payloadIndex);
// prepend IV
encryptedStream.Write(iv, 0, iv.Length);
// read from the stream
count = cipherStream.Read(buffer, 0, Global.BufferSizeLocal);
while (count == Global.BufferSizeLocal)
{
// write to the crypto stream
encryptedStream.Write(buffer, 0, count);
// read from the stream
count = cipherStream.Read(buffer, 0, Global.BufferSizeLocal);
}
// write the final buffer
encryptedStream.Write(buffer, 0, count);
BufferCache.Set(buffer);
// authenticate all data by postpending a hash of all data
encryptedStream.Position = payloadIndex + iv.Length;
using (var hmac = new HMACSHA256(authKey)) {
// calculate a hash of the entire stream excluding the payload and iv
// that can be used to authenticate the received data
byte[] tag = hmac.ComputeHash(encryptedStream);
// write the tag to the end of the encrypted stream
encryptedStream.Write(tag, 0, tag.Length);
}
// reset the stream position
encryptedStream.Position = 0;
// return the complete, encrypted stream
return(encryptedStream);
}
}
}