i2pd/libi2pd/ChaCha20.h

/*
* Copyright (c) 2013-2020, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*
* Kovri go write your own code
*
*/
#ifndef LIBI2PD_CHACHA20_H
#define LIBI2PD_CHACHA20_H

#include <cstdint>
#include <cstring>
#include <inttypes.h>
#include <string.h>
#include "Crypto.h"

#if !OPENSSL_AEAD_CHACHA20_POLY1305
namespace i2p {
    namespace crypto {
        const std::size_t CHACHA20_KEY_BYTES = 32;
        const std::size_t CHACHA20_NOUNCE_BYTES = 12;

        namespace chacha {
            constexpr std::size_t
            blocksize = 64;
            constexpr int rounds = 20;

            struct Chacha20State;

            struct Chacha20Block {
                Chacha20Block() {};

                Chacha20Block(Chacha20Block &&) = delete;

                uint8_t data[blocksize];

                void operator<<(const Chacha20State &st);
            };

            struct Chacha20State {
                Chacha20State() : offset(0) {};

                Chacha20State(Chacha20State &&) = delete;

                Chacha20State &operator+=(const Chacha20State &other) {
                    for (int i = 0; i < 16; i++)
                        data[i] += other.data[i];
                    return *this;
                }

                void Copy(const Chacha20State &other) {
                    memcpy(data, other.data, sizeof(uint32_t) * 16);
                }

                uint32_t data[16];
                Chacha20Block block;
                size_t offset;
            };

            void Chacha20Init(Chacha20State &state, const uint8_t *nonce, const uint8_t *key, uint32_t counter);

            void Chacha20SetCounter(Chacha20State &state, uint32_t counter);

            void Chacha20Encrypt(Chacha20State &state, uint8_t *buf, size_t sz); // encrypt buf in place
        } // namespace chacha
    } // namespace crypto
} // namespace i2p

#endif
#endif