private void testReset()
{
CipherKeyGenerator gen = new Poly1305KeyGenerator();
gen.Init(new KeyGenerationParameters(new SecureRandom(), 256));
byte[] k = gen.GenerateKey();
byte[] m = new byte[10000];
byte[] check = new byte[16];
byte[] output = new byte[16];
// Generate baseline
IMac poly = new Poly1305(new AesFastEngine());
poly.Init(new ParametersWithIV(new KeyParameter(k), new byte[16]));
poly.BlockUpdate(m, 0, m.Length);
poly.DoFinal(check, 0);
// Check reset after doFinal
poly.BlockUpdate(m, 0, m.Length);
poly.DoFinal(output, 0);
if (!Arrays.AreEqual(check, output))
{
Fail("Mac not reset after doFinal");
}
// Check reset
poly.Update((byte)1);
poly.Update((byte)2);
poly.Reset();
poly.BlockUpdate(m, 0, m.Length);
poly.DoFinal(output, 0);
if (!Arrays.AreEqual(check, output))
{
Fail("Mac not reset after doFinal");
}
// Check init resets
poly.Update((byte)1);
poly.Update((byte)2);
poly.Init(new ParametersWithIV(new KeyParameter(k), new byte[16]));
poly.BlockUpdate(m, 0, m.Length);
poly.DoFinal(output, 0);
if (!Arrays.AreEqual(check, output))
{
Fail("Mac not reset after doFinal");
}
}
public void PolyReferenceTests(byte[] key, byte[] iv, byte[] data, byte[] expected)
{
Poly pmac = new Poly(Common.AesFactory);
pmac.Init(key, iv, 16);
pmac.Process(new ArraySegment <byte>(data));
byte[] mac = pmac.Compute();
var bcpoly = new Poly1305(new AesEngine());
bcpoly.Init(new ParametersWithIV(new KeyParameter(key), iv));
bcpoly.BlockUpdate(data, 0, data.Length);
byte[] bcmac = new byte[bcpoly.GetMacSize()];
bcpoly.DoFinal(bcmac, 0);
var _key = string.Join(", ", key.Select(b => $"0x{b:x2}"));
var _iv = string.Join(", ", iv.Select(b => $"0x{b:x2}"));
var _data = string.Join(", ", data.Select(b => $"0x{b:x2}"));
var _expected = string.Join(", ", bcmac.Select(b => $"0x{b:x2}"));
Log.Verbose($"[InlineData(new byte[] {{{_key}}}, new byte[] {{{_iv}}}, new byte[] {{{_data}}}, new byte[] {{{_expected}}})]");
Assert.Equal(expected, mac);
Assert.Equal(expected, bcmac);
}
// Strings are very unsafe to store passwords, or keys in. This is because strings in .NET will always be subject to garbage collection
// which means they can always be dumped out of memory onto disk through various methods, and exploits. However, especially when dealing
// with website logins through forms. It's almost impossible to avoid the risk completely. Below are some examples of best dealing with
// these conditions. Ultimately however, if you can record your secure input directly in byte, char, or SecureString you will always be better off.
public static void Poly()
{
using var poly = new Poly1305(new PinnedMemory <byte>(new byte[] { 63, 61, 77, 20, 63, 61, 77 }, false));
using var hash = new PinnedMemory <byte>(new byte[poly.GetLength()]);
var unsafeCaw = "caw caw caw"; // this is unsafe because string's can't be pinned and are subject to garbage collection, and being written to disk (pagefile).
var caw = new PinnedMemory <byte>(Encoding.UTF8.GetBytes(unsafeCaw), false); // this is now safe but ONLY the variable caw, unsafeCaw is STILL exposed.
unsafeCaw = string.Empty; // unsafeCaw COULD STILL exposed even tho we set it to empty because this depends on garbage collection getting around to clearing it.
poly.UpdateBlock(caw, 0, caw.Length);
poly.DoFinal(hash, 0);
Console.WriteLine(BitConverter.ToString(hash.ToArray()));
// This is a more uncommon but should be safer example of how to use strings with SecureString for input.
using var exampleHash2 = new PinnedMemory <byte>(new byte[poly.GetLength()]);
var secureCaw = new SecureString();
secureCaw.AppendChar('c');
secureCaw.AppendChar('a');
secureCaw.AppendChar('w');
secureCaw.AppendChar(' ');
secureCaw.AppendChar('c');
secureCaw.AppendChar('a');
secureCaw.AppendChar('w');
secureCaw.AppendChar(' ');
secureCaw.AppendChar('c');
secureCaw.AppendChar('a');
secureCaw.AppendChar('w');
secureCaw.MakeReadOnly();
using var pinnedCaw = new PinnedMemory <char>(new char[secureCaw.Length]);
var cawPointer = Marshal.SecureStringToBSTR(secureCaw);
for (var i = 0; i <= secureCaw.Length - 1; i++)
{
var c = (char)Marshal.ReadByte(cawPointer, i * 2);
pinnedCaw[i] = c;
}
using var pinnedCawBytes = new PinnedMemory <byte>(Encoding.UTF8.GetBytes(pinnedCaw.ToArray()), false);
poly.UpdateBlock(pinnedCawBytes, 0, secureCaw.Length);
poly.DoFinal(exampleHash2, 0);
Console.WriteLine(BitConverter.ToString(exampleHash2.ToArray()));
}
static bool crypto_aead_chacha20poly1305_ietf_decrypt_detached(Memory <byte> m, ReadOnlyMemory <byte> c, ReadOnlyMemory <byte> mac, ReadOnlyMemory <byte> ad, ReadOnlyMemory <byte> npub, ReadOnlyMemory <byte> k)
{
var kk = k._AsSegment();
var nn = npub._AsSegment();
var cc = c._AsSegment();
var aa = ad._AsSegment();
var mm = m._AsSegment();
byte[] block0 = new byte[64];
ChaCha7539Engine ctx = new ChaCha7539Engine();
ctx.Init(true, new ParametersWithIV(new KeyParameter(kk.Array, kk.Offset, kk.Count), nn.Array, nn.Offset, nn.Count));
ctx.ProcessBytes(block0, 0, block0.Length, block0, 0);
Poly1305 state = new Poly1305();
state.Init(new KeyParameter(block0, 0, AeadChaCha20Poly1305KeySize));
state.BlockUpdate(aa.Array, aa.Offset, aa.Count);
if ((aa.Count % 16) != 0)
{
state.BlockUpdate(zero15, 0, 16 - (aa.Count % 16));
}
state.BlockUpdate(cc.Array, cc.Offset, cc.Count);
if ((cc.Count % 16) != 0)
{
state.BlockUpdate(zero15, 0, 16 - (cc.Count % 16));
}
byte[] slen = BitConverter.GetBytes((ulong)aa.Count);
if (Env.IsBigEndian)
{
Array.Reverse(slen);
}
state.BlockUpdate(slen, 0, slen.Length);
byte[] mlen = BitConverter.GetBytes((ulong)cc.Count);
if (Env.IsBigEndian)
{
Array.Reverse(mlen);
}
state.BlockUpdate(mlen, 0, mlen.Length);
byte[] computed_mac = new byte[AeadChaCha20Poly1305MacSize];
state.DoFinal(computed_mac, 0);
if (computed_mac.AsSpan().SequenceEqual(mac.Span) == false)
{
return(false);
}
ctx.ProcessBytes(cc.Array, cc.Offset, cc.Count, mm.Array, mm.Offset);
return(true);
}
/// <summary>
/// Branca specification-level token generation
/// </summary>
/// <param name="payload">The payload to be encrypted into the Branca token</param>
/// <param name="key">32-byte private key used to encrypt and decrypt the Branca token</param>
/// <returns>Base62 encoded Branca Token</returns>
public virtual string CreateToken(string payload, byte[] key)
{
if (string.IsNullOrWhiteSpace(payload))
{
throw new ArgumentNullException(nameof(payload));
}
if (!IsValidKey(key))
{
throw new InvalidOperationException("Invalid encryption key");
}
var nonce = new byte[24];
RandomNumberGenerator.Create().GetBytes(nonce);
var timestamp = Convert.ToUInt32(DateTimeOffset.UtcNow.ToUnixTimeSeconds());
// header
var header = new byte[29];
using (var stream = new MemoryStream(header))
{
// version
stream.WriteByte(0xBA);
// timestamp
stream.Write(BitConverter.GetBytes(timestamp), 0, 4);
// nonce
stream.Write(nonce, 0, nonce.Length);
}
var keyMaterial = new KeyParameter(key);
var parameters = new ParametersWithIV(keyMaterial, nonce);
var engine = new XChaChaEngine();
engine.Init(true, parameters);
var plaintextBytes = Encoding.UTF8.GetBytes(payload);
var ciphertext = new byte[plaintextBytes.Length + 16];
engine.ProcessBytes(plaintextBytes, 0, plaintextBytes.Length, ciphertext, 0);
var poly = new Poly1305();
poly.Init(keyMaterial);
poly.BlockUpdate(header, 0, header.Length);
poly.DoFinal(ciphertext, plaintextBytes.Length);
var tokenBytes = new byte[header.Length + ciphertext.Length];
Buffer.BlockCopy(header, 0, tokenBytes, 0, header.Length);
Buffer.BlockCopy(ciphertext, 0, tokenBytes, header.Length, ciphertext.Length);
return(Base62.Encode(tokenBytes));
}
public static void Poly()
{
using var poly = new Poly1305(new PinnedMemory <byte>(new byte[] { 63, 61, 77, 20, 63, 61, 77 }, false));
using var hash = new PinnedMemory <byte>(new byte[poly.GetLength()]);
// digest.UpdateBlock(new byte[] {63, 61, 77, 20, 63, 61, 77, 20, 63, 61, 77}, 0, 11); // This may be exposed without being pinned.
poly.UpdateBlock(new PinnedMemory <byte>(new byte[] { 63, 61, 77, 20, 63, 61, 77, 20, 63, 61, 77 }, false), 0, 11);
poly.DoFinal(hash, 0);
Console.WriteLine(BitConverter.ToString(hash.ToArray()));
}
private static byte[] CalculateMac(byte[] key, byte[] data)
{
var tag = new byte[16];
Poly1305 poly = new Poly1305();
poly.Init(new KeyParameter(key));
poly.BlockUpdate(data, 0, data.Length);
poly.DoFinal(tag, 0);
return(tag);
}
private void CheckVector(byte[] keyMaterial, byte[] input, byte[] tag)
{
Poly1305 poly1305 = new Poly1305();
poly1305.Init(new KeyParameter(keyMaterial));
poly1305.BlockUpdate(input, 0, input.Length);
byte[] mac = new byte[poly1305.GetMacSize()];
poly1305.DoFinal(mac, 0);
if (!Arrays.AreEqual(tag, mac))
{
Fail("rfc7539", Hex.ToHexString(tag), Hex.ToHexString(mac));
}
}
private byte[] CalcMac(byte[] key, byte[] nonce, byte[] cipherText, byte[] ad)
{
var mac = new Poly1305();
var polyKey = EncryptOrDecrypt(true, new byte[32], key, nonce, false);
mac.Init(new KeyParameter(polyKey));
mac.BlockUpdate(ad, 0, ad.Length);
Pad(mac, ad.Length);
mac.BlockUpdate(cipherText, 0, cipherText.Length);
Pad(mac, cipherText.Length);
WriteLE(mac, ad.Length);
WriteLE(mac, cipherText.Length);
var tag = new byte[16];
var macreslen = mac.DoFinal(tag, 0);
Debug.Assert(macreslen == 16);
return(tag);
}
private byte[] EncryptXSalsa20Poly1305(byte[] bytes, byte[] key, byte[] nonce)
{
var salsa = new XSalsa20Engine();
var poly = new Poly1305();
salsa.Init(true, new ParametersWithIV(new KeyParameter(key), nonce));
byte[] subKey = new byte[key.Length];
salsa.ProcessBytes(subKey, 0, key.Length, subKey, 0);
byte[] output = new byte[bytes.Length + poly.GetMacSize()];
salsa.ProcessBytes(bytes, 0, bytes.Length, output, poly.GetMacSize());
poly.Init(new KeyParameter(subKey));
poly.BlockUpdate(output, poly.GetMacSize(), bytes.Length);
poly.DoFinal(output, 0);
return(output);
}
public void BasicPolyTests(int ivBytes, int dataBytes, int macSize)
{
RandomNumberGenerator rng = new RandomNumberGenerator();
byte[] iv = rng.Generate(ivBytes);
byte[] key = rng.Generate(32);
byte[] data = rng.Generate(dataBytes);
Poly pmac = new Poly(Common.AesFactory);
var bcpoly = new Poly1305(new AesEngine());
pmac.Init(key, iv, macSize);
bcpoly.Init(new ParametersWithIV(new KeyParameter(key), iv));
pmac.Process(new ArraySegment <byte>(data));
byte[] mac = pmac.Compute();
bcpoly.BlockUpdate(data, 0, data.Length);
byte[] bcmac = new byte[bcpoly.GetMacSize()];
bcpoly.DoFinal(bcmac, 0);
bcmac = bcmac.Take(macSize).ToArray();
Assert.Equal(bcmac, mac);
}
public void PolyReuseKeyTest(int ivBytes, int dataBytes, int macSize)
{
RandomNumberGenerator rng = new RandomNumberGenerator();
byte[] iv = rng.Generate(ivBytes);
byte[] key = rng.Generate(32);
byte[] data1 = rng.Generate(dataBytes);
byte[] data2 = rng.Generate(dataBytes);
var pmac = new Poly(Common.AesFactory);
pmac.Init(key, iv, macSize);
pmac.Process(new ArraySegment <byte>(data1));
byte[] mac1 = pmac.Compute();
pmac.Init(key, iv, macSize);
pmac.Process(new ArraySegment <byte>(data2));
byte[] mac2 = pmac.Compute();
var bcpoly1 = new Poly1305(new AesEngine());
bcpoly1.Init(new ParametersWithIV(new KeyParameter(key), iv));
bcpoly1.BlockUpdate(data1, 0, data1.Length);
byte[] bcmac1 = new byte[bcpoly1.GetMacSize()];
bcpoly1.DoFinal(bcmac1, 0);
bcmac1 = bcmac1.Take(macSize).ToArray();
var bcpoly2 = new Poly1305(new AesEngine());
bcpoly2.Init(new ParametersWithIV(new KeyParameter(key), iv));
bcpoly2.BlockUpdate(data2, 0, data2.Length);
byte[] bcmac2 = new byte[bcpoly2.GetMacSize()];
bcpoly2.DoFinal(bcmac2, 0);
bcmac2 = bcmac2.Take(macSize).ToArray();
Assert.Equal(bcmac1, mac1);
Assert.Equal(bcmac2, mac2);
}
public static void SelfTest()
{
byte[] key = new byte[] {
0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04, 0xf6, 0xb5, 0xf0,
0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca, 0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0
};
byte[] nonce = new byte[] {
0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
};
byte[] cipherText = new byte[] {
0x64, 0xa0, 0x86, 0x15, 0x75, 0x86, 0x1a, 0xf4, 0x60, 0xf0, 0x62, 0xc7, 0x9b, 0xe6, 0x43, 0xbd,
0x5e, 0x80, 0x5c, 0xfd, 0x34, 0x5c, 0xf3, 0x89, 0xf1, 0x08, 0x67, 0x0a, 0xc7, 0x6c, 0x8c, 0xb2,
0x4c, 0x6c, 0xfc, 0x18, 0x75, 0x5d, 0x43, 0xee, 0xa0, 0x9e, 0xe9, 0x4e, 0x38, 0x2d, 0x26, 0xb0,
0xbd, 0xb7, 0xb7, 0x3c, 0x32, 0x1b, 0x01, 0x00, 0xd4, 0xf0, 0x3b, 0x7f, 0x35, 0x58, 0x94, 0xcf,
0x33, 0x2f, 0x83, 0x0e, 0x71, 0x0b, 0x97, 0xce, 0x98, 0xc8, 0xa8, 0x4a, 0xbd, 0x0b, 0x94, 0x81,
0x14, 0xad, 0x17, 0x6e, 0x00, 0x8d, 0x33, 0xbd, 0x60, 0xf9, 0x82, 0xb1, 0xff, 0x37, 0xc8, 0x55,
0x97, 0x97, 0xa0, 0x6e, 0xf4, 0xf0, 0xef, 0x61, 0xc1, 0x86, 0x32, 0x4e, 0x2b, 0x35, 0x06, 0x38,
0x36, 0x06, 0x90, 0x7b, 0x6a, 0x7c, 0x02, 0xb0, 0xf9, 0xf6, 0x15, 0x7b, 0x53, 0xc8, 0x67, 0xe4,
0xb9, 0x16, 0x6c, 0x76, 0x7b, 0x80, 0x4d, 0x46, 0xa5, 0x9b, 0x52, 0x16, 0xcd, 0xe7, 0xa4, 0xe9,
0x90, 0x40, 0xc5, 0xa4, 0x04, 0x33, 0x22, 0x5e, 0xe2, 0x82, 0xa1, 0xb0, 0xa0, 0x6c, 0x52, 0x3e,
0xaf, 0x45, 0x34, 0xd7, 0xf8, 0x3f, 0xa1, 0x15, 0x5b, 0x00, 0x47, 0x71, 0x8c, 0xbc, 0x54, 0x6a,
0x0d, 0x07, 0x2b, 0x04, 0xb3, 0x56, 0x4e, 0xea, 0x1b, 0x42, 0x22, 0x73, 0xf5, 0x48, 0x27, 0x1a,
0x0b, 0xb2, 0x31, 0x60, 0x53, 0xfa, 0x76, 0x99, 0x19, 0x55, 0xeb, 0xd6, 0x31, 0x59, 0x43, 0x4e,
0xce, 0xbb, 0x4e, 0x46, 0x6d, 0xae, 0x5a, 0x10, 0x73, 0xa6, 0x72, 0x76, 0x27, 0x09, 0x7a, 0x10,
0x49, 0xe6, 0x17, 0xd9, 0x1d, 0x36, 0x10, 0x94, 0xfa, 0x68, 0xf0, 0xff, 0x77, 0x98, 0x71, 0x30,
0x30, 0x5b, 0xea, 0xba, 0x2e, 0xda, 0x04, 0xdf, 0x99, 0x7b, 0x71, 0x4d, 0x6c, 0x6f, 0x2c, 0x29,
0xa6, 0xad, 0x5c, 0xb4, 0x02, 0x2b, 0x02, 0x70, 0x9b,
0xee, 0xad, 0x9d, 0x67, 0x89, 0x0c, 0xbb, 0x22, 0x39, 0x23, 0x36, 0xfe, 0xa1, 0x85, 0x1f, 0x38
};
byte[] aad = new byte[] {
0xf3, 0x33, 0x88, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4e, 0x91
};
byte[] plainText = new byte[] {
0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2d, 0x44, 0x72, 0x61, 0x66, 0x74, 0x73, 0x20,
0x61, 0x72, 0x65, 0x20, 0x64, 0x72, 0x61, 0x66, 0x74, 0x20, 0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65,
0x6e, 0x74, 0x73, 0x20, 0x76, 0x61, 0x6c, 0x69, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x61, 0x20,
0x6d, 0x61, 0x78, 0x69, 0x6d, 0x75, 0x6d, 0x20, 0x6f, 0x66, 0x20, 0x73, 0x69, 0x78, 0x20, 0x6d,
0x6f, 0x6e, 0x74, 0x68, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x6d, 0x61, 0x79, 0x20, 0x62, 0x65,
0x20, 0x75, 0x70, 0x64, 0x61, 0x74, 0x65, 0x64, 0x2c, 0x20, 0x72, 0x65, 0x70, 0x6c, 0x61, 0x63,
0x65, 0x64, 0x2c, 0x20, 0x6f, 0x72, 0x20, 0x6f, 0x62, 0x73, 0x6f, 0x6c, 0x65, 0x74, 0x65, 0x64,
0x20, 0x62, 0x79, 0x20, 0x6f, 0x74, 0x68, 0x65, 0x72, 0x20, 0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65,
0x6e, 0x74, 0x73, 0x20, 0x61, 0x74, 0x20, 0x61, 0x6e, 0x79, 0x20, 0x74, 0x69, 0x6d, 0x65, 0x2e,
0x20, 0x49, 0x74, 0x20, 0x69, 0x73, 0x20, 0x69, 0x6e, 0x61, 0x70, 0x70, 0x72, 0x6f, 0x70, 0x72,
0x69, 0x61, 0x74, 0x65, 0x20, 0x74, 0x6f, 0x20, 0x75, 0x73, 0x65, 0x20, 0x49, 0x6e, 0x74, 0x65,
0x72, 0x6e, 0x65, 0x74, 0x2d, 0x44, 0x72, 0x61, 0x66, 0x74, 0x73, 0x20, 0x61, 0x73, 0x20, 0x72,
0x65, 0x66, 0x65, 0x72, 0x65, 0x6e, 0x63, 0x65, 0x20, 0x6d, 0x61, 0x74, 0x65, 0x72, 0x69, 0x61,
0x6c, 0x20, 0x6f, 0x72, 0x20, 0x74, 0x6f, 0x20, 0x63, 0x69, 0x74, 0x65, 0x20, 0x74, 0x68, 0x65,
0x6d, 0x20, 0x6f, 0x74, 0x68, 0x65, 0x72, 0x20, 0x74, 0x68, 0x61, 0x6e, 0x20, 0x61, 0x73, 0x20,
0x2f, 0xe2, 0x80, 0x9c, 0x77, 0x6f, 0x72, 0x6b, 0x20, 0x69, 0x6e, 0x20, 0x70, 0x72, 0x6f, 0x67,
0x72, 0x65, 0x73, 0x73, 0x2e, 0x2f, 0xe2, 0x80, 0x9d
};
Poly1305 p = new Poly1305();
byte[] pKey = new byte[] { 0x85, 0xd6, 0xbe, 0x78, 0x57, 0x55, 0x6d, 0x33, 0x7f, 0x44, 0x52, 0xfe, 0x42, 0xd5, 0x06, 0xa8, 0x01, 0x03, 0x80, 0x8a, 0xfb, 0x0d, 0xb2, 0xfd, 0x4a, 0xbf, 0xf6, 0xaf, 0x41, 0x49, 0xf5, 0x1b };
KeyParameter paramsX = new KeyParameter(pKey);
p.Init(paramsX);
byte[] msg = UTF8Encoding.ASCII.GetBytes("Cryptographic Forum Research Group");
p.BlockUpdate(msg, 0, msg.Length);
byte[] output = new byte[30];
p.DoFinal(output, 0);
ChaCha20Poly1305 cipher = new ChaCha20Poly1305();
KeyParameter ContentKey = new KeyParameter(key);
AeadParameters parameters = new AeadParameters(ContentKey, 128, nonce, aad);
cipher.Init(true, parameters);
byte[] C = new byte[cipher.GetOutputSize(plainText.Length)];
int len = cipher.ProcessBytes(plainText, 0, plainText.Length, C, 0);
len += cipher.DoFinal(C, len);
}
public int DoFinal(byte[] output, int outOff)
{
byte[] zeros;
if (data.Length + aadLength == 0)
{
InitCipher();
}
int extra = (int)data.Length;
if (forEncryption)
{
// Check.OutputLength(output, outOff, bufOff, extra + macSize, "Output buffer too short");
}
else
{
if (extra < macSize)
{
throw new InvalidCipherTextException("data too short");
}
extra -= macSize;
// Check.OutputLength(output, outOff, extra, "Output buffer too short");
}
// Pad out the AD
zeros = new byte[16 - (aadLength % 16)];
if (zeros.Length != 16)
{
poly.BlockUpdate(zeros, 0, zeros.Length);
}
chacha20.ProcessBytes(data.GetBuffer(), 0, extra, output, outOff);
if (forEncryption)
{
poly.BlockUpdate(output, outOff, extra);
}
else
{
poly.BlockUpdate(data.GetBuffer(), 0, extra);
}
int resultLen = 0;
zeros = new byte[16 - (extra % 16)];
if (zeros.Length != 16)
{
poly.BlockUpdate(zeros, 0, zeros.Length);
}
byte[] lengths = BitConverter.GetBytes((Int64)aadLength);
poly.BlockUpdate(lengths, 0, lengths.Length);
lengths = BitConverter.GetBytes((Int64)extra);
poly.BlockUpdate(lengths, 0, lengths.Length);
macResult = new byte[macSize];
if (poly.DoFinal(macResult, 0) != macResult.Length)
{
throw new Exception("Internal Error");
}
if (forEncryption)
{
resultLen = extra + macSize;
Array.Copy(macResult, 0, output, extra + outOff, macSize);
}
else
{
bool f = true;
for (int i = 0; i < macSize; i++)
{
f &= (macResult[i] == data.GetBuffer()[extra + i]);
}
if (!f)
{
throw new Exception("Authentication Failed");
}
resultLen = extra;
}
Reset(false);
return(resultLen);
}
/// <summary>
/// Branca specification level token decryption.
/// </summary>
/// <param name="token">Base62 encoded Branca token</param>
/// <param name="key">32-byte private key used to encrypt and decrypt the Branca token</param>
/// <returns>Pared and decrypted Branca Token</returns>
public virtual BrancaToken DecryptToken(string token, byte[] key)
{
if (string.IsNullOrWhiteSpace(token))
{
throw new ArgumentNullException(nameof(token));
}
if (!CanReadToken(token))
{
throw new InvalidCastException("Unable to read token");
}
if (!IsValidKey(key))
{
throw new InvalidOperationException("Invalid decryption key");
}
var tokenBytes = Base62.Decode(token);
using (var stream = new MemoryStream(tokenBytes, false))
{
// header
var header = GuaranteedRead(stream, 29);
byte[] nonce;
uint timestamp;
using (var headerStream = new MemoryStream(header))
{
// version
var version = headerStream.ReadByte();
if (version != 0xBA)
{
throw new SecurityTokenException("Unsupported Branca version");
}
// timestamp
var timestampBytes = GuaranteedRead(headerStream, 4);
timestamp = BitConverter.ToUInt32(timestampBytes, 0);
// nonce
nonce = GuaranteedRead(headerStream, 24);
}
// ciphertext
var ciphertextLength = (stream.Length - 16) - stream.Position;
var ciphertext = GuaranteedRead(stream, (int)ciphertextLength);
// tag
var tag = GuaranteedRead(stream, 16);
// XChaCha20-Poly1305
var keyMaterial = new KeyParameter(key);
var parameters = new ParametersWithIV(keyMaterial, nonce);
var headerMac = new byte[16];
var poly1305 = new Poly1305();
poly1305.Init(keyMaterial);
poly1305.BlockUpdate(header, 0, header.Length);
poly1305.DoFinal(headerMac, 0);
if (!headerMac.SequenceEqual(tag))
{
throw new SecurityTokenException("Invalid message authentication code");
}
var engine = new XChaChaEngine();
engine.Init(false, parameters);
var decryptedPlaintext = new byte[ciphertext.Length];
engine.ProcessBytes(ciphertext, 0, ciphertext.Length, decryptedPlaintext, 0);
return(new BrancaToken(
Encoding.UTF8.GetString(decryptedPlaintext),
timestamp));
}
}
private void testSequential()
{
// Sequential test, adapted from test-poly1305aes
int len;
byte[] kr = new byte[32];
byte[] m = new byte[MAXLEN];
byte[] n = new byte[16];
byte[] output = new byte[16];
int c = 0;
IMac mac = new Poly1305(new AesFastEngine());
for (int loop = 0; loop < 13; loop++)
{
len = 0;
for (;;)
{
c++;
mac.Init(new ParametersWithIV(new KeyParameter(kr), n));
mac.BlockUpdate(m, 0, len);
mac.DoFinal(output, 0);
// if (c == 678)
// {
// TestCase tc = CASES[0];
//
// if (!Arrays.AreEqual(tc.key, kr))
// {
// System.err.println("Key bad");
// System.err.println(Hex.ToHexString(tc.key)));
// System.err.println(Hex.ToHexString(kr)));
// System.exit(1);
// }
// if (!Arrays.AreEqual(tc.nonce, n))
// {
// System.err.println("Nonce bad");
// System.exit(1);
// }
// System.out.printf("[%d] m: %s\n", c, Hex.ToHexString(m, 0, len)));
// System.out.printf("[%d] K: %s\n", c, new string(Hex.encodje(kr)));
// System.out.printf("[%d] N: %s\n", c, Hex.ToHexString(n)));
// System.out.printf("[%d] M: ", c);
// }
// System.out.printf("%d/%s\n", c, Hex.ToHexString(out)));
if (len >= MAXLEN)
{
break;
}
n[0] = (byte)(n[0] ^ loop);
for (int i = 0; i < 16; ++i)
{
n[i] ^= output[i];
}
if (len % 2 != 0)
{
for (int i = 0; i < 16; ++i)
{
kr[i] ^= output[i];
}
}
if (len % 3 != 0)
{
for (int i = 0; i < 16; ++i)
{
kr[i + 16] ^= output[i];
}
}
Poly1305KeyGenerator.Clamp(kr);
m[len++] ^= output[0];
}
}
// Output after 13 loops as generated by poly1305 ref
if (c != 13013 || !Arrays.AreEqual(output, Hex.Decode("c96f60a23701a5b0fd2016f58cbe4f7e")))
{
Fail("Sequential Poly1305 " + c, "c96f60a23701a5b0fd2016f58cbe4f7e", Hex.ToHexString(output));
}
}