ZeroTierOne/core/Salsa20.hpp
2020-06-05 13:04:37 -07:00

93 lines
2 KiB
C++

/*
* Copyright (c)2013-2020 ZeroTier, Inc.
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file in the project's root directory.
*
* Change Date: 2024-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2.0 of the Apache License.
*/
/****/
#ifndef ZT_SALSA20_HPP
#define ZT_SALSA20_HPP
#include "Constants.hpp"
#include "Utils.hpp"
#include "TriviallyCopyable.hpp"
#ifdef ZT_ARCH_X64
#define ZT_SALSA20_SSE 1
#endif
#define ZT_SALSA20_KEY_SIZE 32
namespace ZeroTier {
/**
* Salsa20 stream cipher
*
* This supports both the 12-round and 20-round variants.
*
* SECURITY: this code only support up to 2^32 bytes per key. This is
* a minor optimization done here because ZeroTier messages are
* nowhere near this large.
*/
class Salsa20 : public TriviallyCopyable
{
public:
#ifdef ZT_SALSA20_SSE
static constexpr bool accelerated() noexcept { return true; }
#else
static constexpr bool accelerated() noexcept { return false; }
#endif
ZT_INLINE Salsa20() noexcept {}
ZT_INLINE ~Salsa20() noexcept { Utils::burn(&_state,sizeof(_state)); }
/**
* @param key 256-bit (32 byte) key
* @param iv 64-bit initialization vector
*/
ZT_INLINE Salsa20(const void *key,const void *iv) noexcept { init(key,iv); }
/**
* Initialize cipher
*
* @param key Key bits
* @param iv 64-bit initialization vector
*/
void init(const void *key,const void *iv) noexcept;
/**
* Encrypt/decrypt data using Salsa20/12
*
* @param in Input data
* @param out Output buffer
* @param bytes Length of data
*/
void crypt12(const void *in,void *out,unsigned int bytes) noexcept;
/**
* Encrypt/decrypt data using Salsa20/20
*
* @param in Input data
* @param out Output buffer
* @param bytes Length of data
*/
void crypt20(const void *in,void *out,unsigned int bytes) noexcept;
private:
union {
#ifdef ZT_SALSA20_SSE
__m128i v[4];
#endif // ZT_SALSA20_SSE
uint32_t i[16];
} _state;
};
} // namespace ZeroTier
#endif