/// <summary>
/// Creates a new randomly generated key.
/// </summary>
/// <returns>A new randomly generated key.</returns>
public static XChaChaKey Generate()
{
Sodium.Initialize();
GuardedMemoryHandle.Alloc(KeyLengthBytes, out var handle);
var keySpan = handle.DangerousGetSpan();
crypto_secretstream_xchacha20poly1305_keygen(ref MemoryMarshal.GetReference(keySpan));
handle.MakeReadOnly();
return(new XChaChaKey(handle));
}
public static void Alloc(int length, out GuardedMemoryHandle handle)
{
handle = sodium_malloc((UIntPtr)length);
handle.length = length;
// GC.AddMemoryPressure informs the runtime of a large allocation of unmanaged memory that should be
// taken into account when scheduling garbage collection.
// 16 = length of the canary
// 0x3FFF = 4 * dwPageSize (on Windows x64 dwPageSize is 0xFFF = 4096 bytes).
// Sodium rounds (length + dwPageSize) down to the nearest dwPageSize, and then adds 3 * dwPageSize extra.
// Thus (length + 16 + 0x3FFF) is initial amount to allocate and & ~(0xFFF) rounds down to the nearest dwPageSize
GC.AddMemoryPressure((length + 16 + 0x3FFF) & ~0xFFF);
}
/// <summary>
/// Create a new instance from an existing key.
/// </summary>
/// <param name="key">The key.</param>
public XChaChaKey(ReadOnlySpan <byte> key)
{
Sodium.Initialize();
if (key.Length != KeyLengthBytes)
{
throw new ArgumentException("key has invalid length", nameof(key));
}
GuardedMemoryHandle.Alloc(KeyLengthBytes, out this.handle);
this.handle.Write(key);
this.handle.MakeReadOnly();
}
internal XChaChaStreamState()
{
GuardedMemoryHandle.Alloc(Length, out this.handle);
}
public static extern int crypto_secretstream_xchacha20poly1305_push(
GuardedMemoryHandle state,
ref byte c,
out UInt64 clen_p,
in byte m,
public static extern int crypto_secretstream_xchacha20poly1305_init_push(
GuardedMemoryHandle state,
byte[] header,
GuardedMemoryHandle k);
private XChaChaKey(GuardedMemoryHandle handle)
{
this.handle = handle;
}
