/**
 * \file sha512.h
 * \brief This file contains SHA-384 and SHA-512 definitions and functions.
 *
 * The Secure Hash Algorithms 384 and 512 (SHA-384 and SHA-512) cryptographic
 * hash functions are defined in <em>FIPS 180-4: Secure Hash Standard (SHS)</em>.
 */
/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
#ifndef MBEDTLS_SHA512_H
#define MBEDTLS_SHA512_H
#include <stddef.h>
#include <stdint.h>

#include "mbedtls/build_info.h"
#include "mbedtls/private_access.h"

/** SHA-512 input data was malformed. */
#define MBEDTLS_ERR_SHA512_BAD_INPUT_DATA -0x0075

#ifdef __cplusplus
extern "C" {
#endif

#if !defined(MBEDTLS_SHA512_ALT)
// Regular implementation
//

/**
 * \brief          The SHA-512 context structure.
 *
 *                 The structure is used both for SHA-384 and for SHA-512
 *                 checksum calculations. The choice between these two is
 *                 made in the call to mbedtls_sha512_starts().
 */
typedef struct mbedtls_sha512_context {
    uint64_t MBEDTLS_PRIVATE(total)[2];         /*!< The number of Bytes processed. */
    uint64_t MBEDTLS_PRIVATE(state)[8];         /*!< The intermediate digest state. */
    unsigned char MBEDTLS_PRIVATE(buffer)[128]; /*!< The data block being processed. */
#if defined(MBEDTLS_SHA384_C)
    int MBEDTLS_PRIVATE(is384); /*!< Determines which function to use:
                                     0: Use SHA-512, or 1: Use SHA-384. */
#endif
} mbedtls_sha512_context;

#else /* MBEDTLS_SHA512_ALT */
#include "sha512_alt.h"
#endif /* MBEDTLS_SHA512_ALT */

/**
 * \brief          This function initializes a SHA-512 context.
 *
 * \param ctx      The SHA-512 context to initialize. This must
 *                 not be \c NULL.
 */
void mbedtls_sha512_init(mbedtls_sha512_context* ctx);

/**
 * \brief          This function clears a SHA-512 context.
 *
 * \param ctx      The SHA-512 context to clear. This may be \c NULL,
 *                 in which case this function does nothing. If it
 *                 is not \c NULL, it must point to an initialized
 *                 SHA-512 context.
 */
void mbedtls_sha512_free(mbedtls_sha512_context* ctx);

/**
 * \brief          This function clones the state of a SHA-512 context.
 *
 * \param dst      The destination context. This must be initialized.
 * \param src      The context to clone. This must be initialized.
 */
void mbedtls_sha512_clone(mbedtls_sha512_context* dst, const mbedtls_sha512_context* src);

/**
 * \brief          This function starts a SHA-384 or SHA-512 checksum
 *                 calculation.
 *
 * \param ctx      The SHA-512 context to use. This must be initialized.
 * \param is384    Determines which function to use. This must be
 *                 either \c 0 for SHA-512, or \c 1 for SHA-384.
 *
 * \note           When \c MBEDTLS_SHA384_C is not defined,
 *                 \p is384 must be \c 0, or the function will return
 *                 #MBEDTLS_ERR_SHA512_BAD_INPUT_DATA.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
int mbedtls_sha512_starts(mbedtls_sha512_context* ctx, int is384);

/**
 * \brief          This function feeds an input buffer into an ongoing
 *                 SHA-512 checksum calculation.
 *
 * \param ctx      The SHA-512 context. This must be initialized
 *                 and have a hash operation started.
 * \param input    The buffer holding the input data. This must
 *                 be a readable buffer of length \p ilen Bytes.
 * \param ilen     The length of the input data in Bytes.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
int mbedtls_sha512_update(mbedtls_sha512_context* ctx, const unsigned char* input, size_t ilen);

/**
 * \brief          This function finishes the SHA-512 operation, and writes
 *                 the result to the output buffer.
 *
 * \param ctx      The SHA-512 context. This must be initialized
 *                 and have a hash operation started.
 * \param output   The SHA-384 or SHA-512 checksum result.
 *                 This must be a writable buffer of length \c 64 bytes
 *                 for SHA-512, \c 48 bytes for SHA-384.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
int mbedtls_sha512_finish(mbedtls_sha512_context* ctx, unsigned char* output);

/**
 * \brief          This function processes a single data block within
 *                 the ongoing SHA-512 computation.
 *                 This function is for internal use only.
 *
 * \param ctx      The SHA-512 context. This must be initialized.
 * \param data     The buffer holding one block of data. This
 *                 must be a readable buffer of length \c 128 Bytes.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
int mbedtls_internal_sha512_process(mbedtls_sha512_context* ctx, const unsigned char data[128]);

/**
 * \brief          This function calculates the SHA-512 or SHA-384
 *                 checksum of a buffer.
 *
 *                 The function allocates the context, performs the
 *                 calculation, and frees the context.
 *
 *                 The SHA-512 result is calculated as
 *                 output = SHA-512(input buffer).
 *
 * \param input    The buffer holding the input data. This must be
 *                 a readable buffer of length \p ilen Bytes.
 * \param ilen     The length of the input data in Bytes.
 * \param output   The SHA-384 or SHA-512 checksum result.
 *                 This must be a writable buffer of length \c 64 bytes
 *                 for SHA-512, \c 48 bytes for SHA-384.
 * \param is384    Determines which function to use. This must be either
 *                 \c 0 for SHA-512, or \c 1 for SHA-384.
 *
 * \note           When \c MBEDTLS_SHA384_C is not defined, \p is384 must
 *                 be \c 0, or the function will return
 *                 #MBEDTLS_ERR_SHA512_BAD_INPUT_DATA.
 *
 * \return         \c 0 on success.
 * \return         A negative error code on failure.
 */
int mbedtls_sha512(const unsigned char* input, size_t ilen, unsigned char* output, int is384);

#if defined(MBEDTLS_SELF_TEST)

/**
 * \brief          The SHA-384 or SHA-512 checkup routine.
 *
 * \return         \c 0 on success.
 * \return         \c 1 on failure.
 */
int mbedtls_sha512_self_test(int verbose);
#endif /* MBEDTLS_SELF_TEST */

#ifdef __cplusplus
}
#endif

#endif /* mbedtls_sha512.h */
