d297157fe8
Now that descriptions of error codes no longer have to be on the same line for the sake of generate_errors.pl, move them to their own line before the definition. This aligns them with what we do for other definitions, and means that we no longer need to have very long lines containing both the C definition and the comment. ``` perl -i -pe 's~^(#define +MBEDTLS_ERR_\w+ +-\w+) */\*[*!]<(.*)\*/~/**$2*/\n$1~' include/mbedtls/*.h ``` This commit does not change the output of generate_errors.pl. Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
215 lines
8.1 KiB
C
215 lines
8.1 KiB
C
/**
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* \file chacha20.h
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*
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* \brief This file contains ChaCha20 definitions and functions.
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*
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* ChaCha20 is a stream cipher that can encrypt and decrypt
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* information. ChaCha was created by Daniel Bernstein as a variant of
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* its Salsa cipher https://cr.yp.to/chacha/chacha-20080128.pdf
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* ChaCha20 is the variant with 20 rounds, that was also standardized
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* in RFC 7539.
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*
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* \author Daniel King <damaki.gh@gmail.com>
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*/
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/*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBEDTLS_CHACHA20_H
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#define MBEDTLS_CHACHA20_H
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#include "mbedtls/private_access.h"
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#include "mbedtls/build_info.h"
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#include <stdint.h>
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#include <stddef.h>
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/** Invalid input parameter(s). */
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#define MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA -0x0051
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#ifdef __cplusplus
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extern "C" {
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#endif
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#if !defined(MBEDTLS_CHACHA20_ALT)
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typedef struct mbedtls_chacha20_context
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{
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uint32_t MBEDTLS_PRIVATE(state)[16]; /*! The state (before round operations). */
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uint8_t MBEDTLS_PRIVATE(keystream8)[64]; /*! Leftover keystream bytes. */
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size_t MBEDTLS_PRIVATE(keystream_bytes_used); /*! Number of keystream bytes already used. */
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}
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mbedtls_chacha20_context;
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#else /* MBEDTLS_CHACHA20_ALT */
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#include "chacha20_alt.h"
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#endif /* MBEDTLS_CHACHA20_ALT */
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/**
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* \brief This function initializes the specified ChaCha20 context.
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*
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* It must be the first API called before using
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* the context.
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*
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* It is usually followed by calls to
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* \c mbedtls_chacha20_setkey() and
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* \c mbedtls_chacha20_starts(), then one or more calls to
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* to \c mbedtls_chacha20_update(), and finally to
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* \c mbedtls_chacha20_free().
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*
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* \param ctx The ChaCha20 context to initialize.
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* This must not be \c NULL.
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*/
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void mbedtls_chacha20_init( mbedtls_chacha20_context *ctx );
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/**
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* \brief This function releases and clears the specified
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* ChaCha20 context.
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*
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* \param ctx The ChaCha20 context to clear. This may be \c NULL,
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* in which case this function is a no-op. If it is not
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* \c NULL, it must point to an initialized context.
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*
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*/
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void mbedtls_chacha20_free( mbedtls_chacha20_context *ctx );
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/**
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* \brief This function sets the encryption/decryption key.
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*
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* \note After using this function, you must also call
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* \c mbedtls_chacha20_starts() to set a nonce before you
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* start encrypting/decrypting data with
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* \c mbedtls_chacha_update().
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*
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* \param ctx The ChaCha20 context to which the key should be bound.
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* It must be initialized.
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* \param key The encryption/decryption key. This must be \c 32 Bytes
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* in length.
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*
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* \return \c 0 on success.
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* \return #MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA if ctx or key is NULL.
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*/
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int mbedtls_chacha20_setkey( mbedtls_chacha20_context *ctx,
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const unsigned char key[32] );
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/**
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* \brief This function sets the nonce and initial counter value.
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*
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* \note A ChaCha20 context can be re-used with the same key by
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* calling this function to change the nonce.
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*
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* \warning You must never use the same nonce twice with the same key.
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* This would void any confidentiality guarantees for the
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* messages encrypted with the same nonce and key.
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*
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* \param ctx The ChaCha20 context to which the nonce should be bound.
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* It must be initialized and bound to a key.
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* \param nonce The nonce. This must be \c 12 Bytes in size.
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* \param counter The initial counter value. This is usually \c 0.
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*
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* \return \c 0 on success.
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* \return #MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA if ctx or nonce is
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* NULL.
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*/
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int mbedtls_chacha20_starts( mbedtls_chacha20_context* ctx,
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const unsigned char nonce[12],
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uint32_t counter );
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/**
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* \brief This function encrypts or decrypts data.
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*
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* Since ChaCha20 is a stream cipher, the same operation is
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* used for encrypting and decrypting data.
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*
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* \note The \p input and \p output pointers must either be equal or
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* point to non-overlapping buffers.
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*
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* \note \c mbedtls_chacha20_setkey() and
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* \c mbedtls_chacha20_starts() must be called at least once
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* to setup the context before this function can be called.
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*
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* \note This function can be called multiple times in a row in
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* order to encrypt of decrypt data piecewise with the same
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* key and nonce.
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*
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* \param ctx The ChaCha20 context to use for encryption or decryption.
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* It must be initialized and bound to a key and nonce.
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* \param size The length of the input data in Bytes.
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* \param input The buffer holding the input data.
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* This pointer can be \c NULL if `size == 0`.
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* \param output The buffer holding the output data.
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* This must be able to hold \p size Bytes.
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* This pointer can be \c NULL if `size == 0`.
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*
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* \return \c 0 on success.
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* \return A negative error code on failure.
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*/
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int mbedtls_chacha20_update( mbedtls_chacha20_context *ctx,
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size_t size,
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const unsigned char *input,
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unsigned char *output );
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/**
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* \brief This function encrypts or decrypts data with ChaCha20 and
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* the given key and nonce.
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*
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* Since ChaCha20 is a stream cipher, the same operation is
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* used for encrypting and decrypting data.
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*
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* \warning You must never use the same (key, nonce) pair more than
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* once. This would void any confidentiality guarantees for
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* the messages encrypted with the same nonce and key.
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*
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* \note The \p input and \p output pointers must either be equal or
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* point to non-overlapping buffers.
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*
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* \param key The encryption/decryption key.
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* This must be \c 32 Bytes in length.
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* \param nonce The nonce. This must be \c 12 Bytes in size.
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* \param counter The initial counter value. This is usually \c 0.
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* \param size The length of the input data in Bytes.
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* \param input The buffer holding the input data.
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* This pointer can be \c NULL if `size == 0`.
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* \param output The buffer holding the output data.
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* This must be able to hold \p size Bytes.
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* This pointer can be \c NULL if `size == 0`.
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*
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* \return \c 0 on success.
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* \return A negative error code on failure.
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*/
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int mbedtls_chacha20_crypt( const unsigned char key[32],
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const unsigned char nonce[12],
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uint32_t counter,
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size_t size,
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const unsigned char* input,
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unsigned char* output );
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#if defined(MBEDTLS_SELF_TEST)
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/**
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* \brief The ChaCha20 checkup routine.
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*
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* \return \c 0 on success.
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* \return \c 1 on failure.
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*/
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int mbedtls_chacha20_self_test( int verbose );
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#endif /* MBEDTLS_SELF_TEST */
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#ifdef __cplusplus
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}
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#endif
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#endif /* MBEDTLS_CHACHA20_H */
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