lc_chacha20_poly1305.h

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/*
 * Copyright (C) 2022 - 2025, Stephan Mueller <smueller@chronox.de>
 *
 * License: see LICENSE file in root directory
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
 
#ifndef LC_CHACHA20_POLY1305_H
#define LC_CHACHA20_POLY1305_H
 
#include "lc_aead.h"
#include "lc_chacha20.h"
#include "lc_memset_secure.h"
#include "lc_poly1305.h"
 
#ifdef __cplusplus
extern "C" {
#endif

struct lc_chacha20_poly1305_cryptor {
        struct lc_sym_ctx chacha20;
        struct lc_poly1305_context poly1305_ctx;
        size_t datalen;
        size_t aadlen;
};
 
#define LC_CHACHA20_POLY1305_STATE_SIZE (LC_SYM_STATE_SIZE(lc_chacha20))
#define LC_CHACHA20_POLY1305_CTX_SIZE                                          \
        (sizeof(struct lc_aead) +                                              \
         sizeof(struct lc_chacha20_poly1305_cryptor) +                         \
         LC_CHACHA20_POLY1305_STATE_SIZE)
 
/* AES-CBC with HMAC based AEAD-algorithm */
extern const struct lc_aead *lc_chacha20_poly1305_aead;
 
#define _LC_CHACHA20_POLY1305_SET_CTX(name)                                    \
        _LC_SYM_SET_CTX((&name->chacha20), lc_chacha20, name,                  \
                        (sizeof(struct lc_chacha20_poly1305_cryptor)));        \
        (name)->datalen = 0;                                                   \
        (name)->aadlen = 0
 
#define LC_CHACHA20_POLY1305_SET_CTX(name)                                     \
        LC_AEAD_CTX(name, lc_chacha20_poly1305_aead);                          \
        _LC_CHACHA20_POLY1305_SET_CTX(                                         \
                ((struct lc_chacha20_poly1305_cryptor *)name->aead_state))

int lc_chacha20_poly1305_alloc(struct lc_aead_ctx **ctx);

#define LC_CHACHA20_POLY1305_CTX_ON_STACK(name)                                     \
        _Pragma("GCC diagnostic push")                                              \
                _Pragma("GCC diagnostic ignored \"-Wvla\"") _Pragma(                \
                        "GCC diagnostic ignored \"-Wdeclaration-after-statement\"") \
                        LC_ALIGNED_BUFFER(name##_ctx_buf,                           \
                                          LC_CHACHA20_POLY1305_CTX_SIZE,            \
                                          LC_MEM_COMMON_ALIGNMENT);                 \
        struct lc_aead_ctx *name = (struct lc_aead_ctx *)name##_ctx_buf;            \
        LC_CHACHA20_POLY1305_SET_CTX(name);                                         \
        lc_aead_zero(name);                                                         \
        _Pragma("GCC diagnostic pop")
 
#ifdef __cplusplus
}
#endif
 
#endif /* LC_CHACHA20_POLY1305_H */