/// <summary>
/// Encrypt data with Salsa20
/// </summary>
/// <param name="input">Input stream to encrypt</param>
/// <param name="output">Output stream</param>
/// <param name="key">Key</param>
/// <param name="nonce">Nonce</param>
/// <param name="notifyProgression">Notify progression method</param>
/// <param name="bufferSize">Buffer size</param>
public static void Encrypt(Stream input, Stream output, byte[] key, byte[] nonce, Action <int> notifyProgression = null, int bufferSize = 4096)
{
Salsa20Engine engine = new Salsa20Engine();
ParametersWithIV parameters = new ParametersWithIV(new KeyParameter(key, 0, key.Length), nonce, 0, nonce.Length);
engine.Init(true, parameters);
int bytesRead;
byte[] buffer = new byte[bufferSize];
byte[] enc = new byte[bufferSize];
do
{
bytesRead = input.Read(buffer, 0, bufferSize);
if (bytesRead > 0)
{
engine.ProcessBytes(buffer, 0, bytesRead, enc, 0);
output.Write(enc, 0, bytesRead);
if (notifyProgression != null)
{
notifyProgression(bytesRead);
}
}
} while (bytesRead == bufferSize);
}
private void salsa20Test1(
int rounds,
ICipherParameters parameters,
string v0,
string v192,
string v256,
string v448)
{
IStreamCipher salsa = new Salsa20Engine(rounds);
byte[] buf = new byte[64];
salsa.Init(true, parameters);
for (int i = 0; i != 7; i++)
{
salsa.ProcessBytes(zeroes, 0, 64, buf, 0);
switch (i)
{
case 0:
if (!AreEqual(buf, Hex.Decode(v0)))
{
mismatch("v0/" + rounds, v0, buf);
}
break;
case 3:
if (!AreEqual(buf, Hex.Decode(v192)))
{
mismatch("v192/" + rounds, v192, buf);
}
break;
case 4:
if (!AreEqual(buf, Hex.Decode(v256)))
{
mismatch("v256/" + rounds, v256, buf);
}
break;
default:
// ignore
break;
}
}
for (int i = 0; i != 64; i++)
{
buf[i] = salsa.ReturnByte(zeroes[i]);
}
if (!AreEqual(buf, Hex.Decode(v448)))
{
mismatch("v448", v448, buf);
}
}
/// <summary>
/// Decrypt data with Salsa20
/// </summary>
/// <param name="data">Data to decrypt</param>
/// <param name="key">Key</param>
/// <param name="nonce">Nonce</param>
/// <returns>Decrypted data</returns>
public static byte[] Decrypt(byte[] data, byte[] key, byte[] nonce)
{
byte[] dec = new byte[data.Length];
Salsa20Engine engine = new Salsa20Engine();
ParametersWithIV parameters = new ParametersWithIV(new KeyParameter(key, 0, key.Length), nonce, 0, nonce.Length);
engine.Init(false, parameters);
engine.ProcessBytes(data, 0, data.Length, dec, 0);
return(dec);
}
private byte[] SalsaB(byte[] Key, byte[] Vector, byte[] Data)
{
int len = Data.Length;
int ct = 0;
byte[] output = new byte[len];
Salsa20Engine salsa = new Salsa20Engine();
salsa.Init(true, Key, Vector);
while (ct < len)
{
salsa.ProcessBytes(Data, ct, 64, output, ct);
ct += 64;
}
return(output);
}
/// <summary>
/// Gets an ID for the key.
/// </summary>
/// <returns>
/// A byte array that can be used as an identifier for the key.
/// </returns>
/// <remarks>
/// C# implementation of the GO code at
/// <see href="https://github.com/libp2p/go-libp2p-pnet/blob/bed5e6afdf9099121029f6fb675be12a50196114/fingerprint.go#L10"/>.
/// </remarks>
public byte[] Fingerprint()
{
// Encrypt data first so we don't feed PSK to hash function.
// Salsa20 function is not reversible thus increasing our security margin.
var encrypted = new byte[64];
var nonce = Encoding.ASCII.GetBytes("finprint");
var cipher = new Salsa20Engine();
cipher.Init(true, new ParametersWithIV(new KeyParameter(this.Value), nonce));
cipher.ProcessBytes(encrypted, 0, encrypted.Length, encrypted, 0);
// Then do Shake-128 hash to reduce its length.
// This way if for some reason Shake is broken and Salsa20 preimage is possible,
// attacker has only half of the bytes necessary to recreate psk.
return(MultiHash
.GetHashAlgorithm("shake-128")
.ComputeHash(encrypted));
}
private void salsa20Test2(
ICipherParameters parameters,
string v0,
string v65472,
string v65536)
{
IStreamCipher salsa = new Salsa20Engine();
byte[] buf = new byte[64];
salsa.Init(true, parameters);
for (int i = 0; i != 1025; i++)
{
salsa.ProcessBytes(zeroes, 0, 64, buf, 0);
switch (i)
{
case 0:
if (!AreEqual(buf, Hex.Decode(v0)))
{
mismatch("v0", v0, buf);
}
break;
case 1023:
if (!AreEqual(buf, Hex.Decode(v65472)))
{
mismatch("v65472", v65472, buf);
}
break;
case 1024:
if (!AreEqual(buf, Hex.Decode(v65536)))
{
mismatch("v65536", v65536, buf);
}
break;
default:
// ignore
break;
}
}
}
private byte[] Salsa2Test(byte[] Key, byte[] Vector, byte[] Data)
{
int len = Data.Length;
int ct = 0;
byte[] output = new byte[len];
Salsa20Engine salsa = new Salsa20Engine();
salsa.Init(true, Key, Vector);
while (ct < len)
{
salsa.ProcessBytes(Data, ct, 64, output, ct);
ct += 64;
}
return output;
}