public void Encrypt(ReadOnlySpan <byte> nonce, ReadOnlySpan <byte> source,
Span <byte> destination, Span <byte> tag, ReadOnlySpan <byte> associatedData = default)
{
if (nonce.Length != NonceSize)
{
throw new ArgumentException(@"Nonce size must be 12 bytes", nameof(nonce));
}
if (destination.Length != source.Length)
{
throw new ArgumentException(string.Empty, nameof(destination));
}
_chacha20.SetIV(nonce);
_chacha20.SetCounter(1);
_chacha20.Update(source, destination);
var buffer = _buffer.AsSpan(0, Poly1305Utils.KeySize);
_chacha20.SetCounter(0);
_chacha20.Update(Init, buffer);
using var poly1305 = Poly1305Utils.Create(buffer);
poly1305.Update(associatedData);
poly1305.Update(destination);
Span <byte> block = _buffer.AsSpan(Poly1305Utils.BlockSize);
BinaryPrimitives.WriteUInt64LittleEndian(block, (ulong)associatedData.Length);
BinaryPrimitives.WriteUInt64LittleEndian(block[8..], (ulong)source.Length);
public void Test(string keyHex, string plainHex, string cipherHex)
{
var key = keyHex.FromHex();
Test(new Poly1305SF(key), plainHex, cipherHex);
Test(new Poly1305X86(key), plainHex, cipherHex);
Test(Poly1305Utils.Create(key), plainHex, cipherHex);
}
public void Decrypt(ReadOnlySpan <byte> nonce, ReadOnlySpan <byte> source, ReadOnlySpan <byte> tag,
Span <byte> destination, ReadOnlySpan <byte> associatedData = default)
{
if (nonce.Length != NonceSize)
{
throw new ArgumentException(@"Nonce size must be 24 bytes", nameof(nonce));
}
if (destination.Length != source.Length)
{
throw new ArgumentException(string.Empty, nameof(destination));
}
_chacha20.SetIV(nonce);
var buffer = _buffer.AsSpan(0, Poly1305Utils.KeySize);
_chacha20.SetCounter(0);
_chacha20.Update(Init, buffer);
using var poly1305 = Poly1305Utils.Create(buffer);
poly1305.Update(associatedData);
poly1305.Update(source);
Span <byte> block = _buffer.AsSpan(TagSize);
BinaryPrimitives.WriteUInt64LittleEndian(block, (ulong)associatedData.Length);
BinaryPrimitives.WriteUInt64LittleEndian(block.Slice(8), (ulong)source.Length);
poly1305.Update(block);
poly1305.GetMac(block);
if (!block.SequenceEqual(tag))
{
throw new ArgumentException(@"Unable to decrypt input with these parameters.");
}
_chacha20.SetCounter(1);
_chacha20.Update(source, destination);
}
