LibCrypto: Add Poly1305

Userland/Libraries/LibCrypto/Authentication/Poly1305.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2022, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/ByteBuffer.h>
+
+namespace Crypto::Authentication {
+
+struct State {
+    u32 r[4] {};
+    u32 s[4] {};
+    u64 a[8] {};
+    u8 blocks[17] {};
+    u8 block_count {};
+};
+
+class Poly1305 {
+
+public:
+    explicit Poly1305(ReadonlyBytes key);
+    void update(ReadonlyBytes message);
+    ErrorOr<ByteBuffer> digest();
+
+private:
+    void process_block();
+
+    State m_state;
+};
+
+}