public static void Encrypt(StreamCtx ctx, Stream instr, Stream outstr, StreamCipherMonitor monitor)
{
if (instr.Length <= 0)
{
return;
}
byte[] buffer = new byte[ctx.BlockSize()];
byte[] output = new byte[ctx.BlockSize()];
bool ivInited = false;
int i = 0;
if (monitor != null)
{
monitor.Progress(0, instr.Length);
}
do
{
if (monitor != null)
{
if (monitor.ShouldStop())
{
return;
}
monitor.Progress(instr.Position, instr.Length);
}
i = instr.Read(buffer, 0, ctx.BlockSize());
if (i < 0)
{
i = 0;
}
if ((i > 0) && (!ivInited)) // first block
{
ivInited = true;
if (ctx.Mode == Mode.CBC)
{
Array.Copy(ctx.IV, 0, output, 0, output.Length);
}
}
if ((i <= 0) || (i < buffer.Length)) // lastBlock
{
PrepareLastBuffer(buffer, i);
PrepareBuffer(ctx.Mode, buffer, output);
ctx.Ibc.Cipher(buffer, output);
outstr.Write(output, 0, output.Length);
break;
}
PrepareBuffer(ctx.Mode, buffer, output);
ctx.Ibc.Cipher(buffer, output);
outstr.Write(output, 0, output.Length);
} while(true);
outstr.Flush();
if (monitor != null)
{
if (!monitor.ShouldStop())
{
monitor.Progress(instr.Length, instr.Length);
}
}
}
public static void Decrypt(StreamCtx ctx, Stream instr, Stream outstr, StreamCipherMonitor monitor)
{
// in this method we fail silently
if (instr.Length <= 0)
{
return;
}
byte[] buffer = new byte[ctx.BlockSize()];
byte[] output = new byte[ctx.BlockSize()];
int i = 0;
bool ivInited = false;
byte[] iv = new byte[ctx.BlockSize()];
// to delay the output, required because we do not rely in
// instr.Length to find the end of stream
bool lastInited = false;
byte[] last = new byte[ctx.BlockSize()];
if (monitor != null)
{
monitor.Progress(0, instr.Length);
}
do
{
if (monitor != null)
{
if (monitor.ShouldStop())
{
return;
}
monitor.Progress(instr.Position, instr.Length);
}
i = instr.Read(buffer, 0, buffer.Length);
if (i < 0)
{
i = 0;
}
// must be a multiple of ctx.blockSize
if ((i > 0) && (i != buffer.Length))
{
return; //throw new Exception();
}
if ((i > 0) && (!ivInited))
{
ivInited = true;
if (ctx.Mode == Mode.CBC)
{
Array.Copy(ctx.IV, 0, iv, 0, ctx.IV.Length);
}
}
if (i <= 0) //lastblock
{
// buffer has no data
if (!lastInited)
{
return; // throw new Exception();
}
Array.Copy(last, output, output.Length);
// remove padd data
int k = (int)output[output.Length - 1];
if (k > output.Length)
{
return;
}
outstr.Write(output, 0, output.Length - k);
break;
}
ctx.Ibc.InvCipher(buffer, output);
if (ctx.Mode == Mode.CBC)
{
PrepareBuffer(ctx.Mode, output, iv);
Array.Copy(buffer, iv, buffer.Length);
}
//delay output
if (!lastInited)
{
Array.Copy(output, last, output.Length);
lastInited = true;
}
else
{
outstr.Write(last, 0, last.Length);
Array.Copy(output, last, output.Length);
}
} while(true);
outstr.Flush();
if (monitor != null)
{
if (!monitor.ShouldStop())
{
monitor.Progress(instr.Length, instr.Length);
}
}
}
