#include "config.h"
#include "config.h"
#include MBEDTLS_CONFIG_FILE
#include MBEDTLS_CONFIG_FILE
#include "poly1305.h"
#include "poly1305.h"
#include "chacha20.h"
#include "chacha20.h"
#include "chachapoly_alt.h"
#include "chachapoly_alt.h"
#define MBEDTLS_CHACHAPOLY_H
#define MBEDTLS_ERR_CHACHAPOLY_BAD_STATE -84 /**< The requested operation is not permitted in the current state. */
#define MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED -86 /**< Authenticated decryption failed: data was not authentic. */
void mbedtls_chachapoly_init( mbedtls_chachapoly_context *ctx );
/** * \brief This function initializes the specified ChaCha20-Poly1305 context. * * It must be the first API called before using * the context. It must be followed by a call to * \c mbedtls_chachapoly_setkey() before any operation can be * done, and to \c mbedtls_chachapoly_free() once all * operations with that context have been finished. * * In order to encrypt or decrypt full messages at once, for * each message you should make a single call to * \c mbedtls_chachapoly_crypt_and_tag() or * \c mbedtls_chachapoly_auth_decrypt(). * * In order to encrypt messages piecewise, for each * message you should make a call to * \c mbedtls_chachapoly_starts(), then 0 or more calls to * \c mbedtls_chachapoly_update_aad(), then 0 or more calls to * \c mbedtls_chachapoly_update(), then one call to * \c mbedtls_chachapoly_finish(). * * \warning Decryption with the piecewise API is discouraged! Always * use \c mbedtls_chachapoly_auth_decrypt() when possible! * * If however this is not possible because the data is too * large to fit in memory, you need to: * * - call \c mbedtls_chachapoly_starts() and (if needed) * \c mbedtls_chachapoly_update_aad() as above, * - call \c mbedtls_chachapoly_update() multiple times and * ensure its output (the plaintext) is NOT used in any other * way than placing it in temporary storage at this point, * - call \c mbedtls_chachapoly_finish() to compute the * authentication tag and compared it in constant time to the * tag received with the ciphertext. * * If the tags are not equal, you must immediately discard * all previous outputs of \c mbedtls_chachapoly_update(), * otherwise you can now safely use the plaintext. * * \param ctx The ChachaPoly context to initialize. Must not be \c NULL. */
void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx );
/** * \brief This function releases and clears the specified * ChaCha20-Poly1305 context. * * \param ctx The ChachaPoly context to clear. This may be \c NULL, in which * case this function is a no-op. */
int mbedtls_chachapoly_setkey( mbedtls_chachapoly_context *ctx,
const unsigned char key[32] );
/** * \brief This function sets the ChaCha20-Poly1305 * symmetric encryption key. * * \param ctx The ChaCha20-Poly1305 context to which the key should be * bound. This must be initialized. * \param key The \c 256 Bit (\c 32 Bytes) key. * * \return \c 0 on success. * \return A negative error code on failure. */
int mbedtls_chachapoly_starts( mbedtls_chachapoly_context *ctx,
const unsigned char nonce[12],
mbedtls_chachapoly_mode_t mode );
/** * \brief This function starts a ChaCha20-Poly1305 encryption or * decryption operation. * * \warning You must never use the same nonce twice with the same key. * This would void any confidentiality and authenticity * guarantees for the messages encrypted with the same nonce * and key. * * \note If the context is being used for AAD only (no data to * encrypt or decrypt) then \p mode can be set to any value. * * \warning Decryption with the piecewise API is discouraged, see the * warning on \c mbedtls_chachapoly_init(). * * \param ctx The ChaCha20-Poly1305 context. This must be initialized * and bound to a key. * \param nonce The nonce/IV to use for the message. * This must be a redable buffer of length \c 12 Bytes. * \param mode The operation to perform: #MBEDTLS_CHACHAPOLY_ENCRYPT or * #MBEDTLS_CHACHAPOLY_DECRYPT (discouraged, see warning). * * \return \c 0 on success. * \return A negative error code on failure. */
int mbedtls_chachapoly_update_aad( mbedtls_chachapoly_context *ctx,
const unsigned char *aad,
size_t aad_len );
/** * \brief This function feeds additional data to be authenticated * into an ongoing ChaCha20-Poly1305 operation. * * The Additional Authenticated Data (AAD), also called * Associated Data (AD) is only authenticated but not * encrypted nor included in the encrypted output. It is * usually transmitted separately from the ciphertext or * computed locally by each party. * * \note This function is called before data is encrypted/decrypted. * I.e. call this function to process the AAD before calling * \c mbedtls_chachapoly_update(). * * You may call this function multiple times to process * an arbitrary amount of AAD. It is permitted to call * this function 0 times, if no AAD is used. * * This function cannot be called any more if data has * been processed by \c mbedtls_chachapoly_update(), * or if the context has been finished. * * \warning Decryption with the piecewise API is discouraged, see the * warning on \c mbedtls_chachapoly_init(). * * \param ctx The ChaCha20-Poly1305 context. This must be initialized * and bound to a key. * \param aad_len The length in Bytes of the AAD. The length has no * restrictions. * \param aad Buffer containing the AAD. * This pointer can be \c NULL if `aad_len == 0`. * * \return \c 0 on success. * \return #MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA * if \p ctx or \p aad are NULL. * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE * if the operations has not been started or has been * finished, or if the AAD has been finished. */
int mbedtls_chachapoly_update( mbedtls_chachapoly_context *ctx,
size_t len,
const unsigned char *input,
unsigned char *output );
/** * \brief Thus function feeds data to be encrypted or decrypted * into an on-going ChaCha20-Poly1305 * operation. * * The direction (encryption or decryption) depends on the * mode that was given when calling * \c mbedtls_chachapoly_starts(). * * You may call this function multiple times to process * an arbitrary amount of data. It is permitted to call * this function 0 times, if no data is to be encrypted * or decrypted. * * \warning Decryption with the piecewise API is discouraged, see the * warning on \c mbedtls_chachapoly_init(). * * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. * \param len The length (in bytes) of the data to encrypt or decrypt. * \param input The buffer containing the data to encrypt or decrypt. * This pointer can be \c NULL if `len == 0`. * \param output The buffer to where the encrypted or decrypted data is * written. This must be able to hold \p len bytes. * This pointer can be \c NULL if `len == 0`. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE * if the operation has not been started or has been * finished. * \return Another negative error code on other kinds of failure. */
int mbedtls_chachapoly_finish( mbedtls_chachapoly_context *ctx,
unsigned char mac[16] );
/** * \brief This function finished the ChaCha20-Poly1305 operation and * generates the MAC (authentication tag). * * \param ctx The ChaCha20-Poly1305 context to use. This must be initialized. * \param mac The buffer to where the 128-bit (16 bytes) MAC is written. * * \warning Decryption with the piecewise API is discouraged, see the * warning on \c mbedtls_chachapoly_init(). * * \return \c 0 on success. * \return #MBEDTLS_ERR_CHACHAPOLY_BAD_STATE * if the operation has not been started or has been * finished. * \return Another negative error code on other kinds of failure. */
int mbedtls_chachapoly_encrypt_and_tag( mbedtls_chachapoly_context *ctx,
size_t length,
const unsigned char nonce[12],
const unsigned char *aad,
size_t aad_len,
const unsigned char *input,
unsigned char *output,
unsigned char tag[16] );
/** * \brief This function performs a complete ChaCha20-Poly1305 * authenticated encryption with the previously-set key. * * \note Before using this function, you must set the key with * \c mbedtls_chachapoly_setkey(). * * \warning You must never use the same nonce twice with the same key. * This would void any confidentiality and authenticity * guarantees for the messages encrypted with the same nonce * and key. * * \param ctx The ChaCha20-Poly1305 context to use (holds the key). * This must be initialized. * \param length The length (in bytes) of the data to encrypt or decrypt. * \param nonce The 96-bit (12 bytes) nonce/IV to use. * \param aad The buffer containing the additional authenticated * data (AAD). This pointer can be \c NULL if `aad_len == 0`. * \param aad_len The length (in bytes) of the AAD data to process. * \param input The buffer containing the data to encrypt or decrypt. * This pointer can be \c NULL if `ilen == 0`. * \param output The buffer to where the encrypted or decrypted data * is written. This pointer can be \c NULL if `ilen == 0`. * \param tag The buffer to where the computed 128-bit (16 bytes) MAC * is written. This must not be \c NULL. * * \return \c 0 on success. * \return A negative error code on failure. */
int mbedtls_chachapoly_auth_decrypt( mbedtls_chachapoly_context *ctx,
size_t length,
const unsigned char nonce[12],
const unsigned char *aad,
size_t aad_len,
const unsigned char tag[16],
const unsigned char *input,
unsigned char *output );
/** * \brief This function performs a complete ChaCha20-Poly1305 * authenticated decryption with the previously-set key. * * \note Before using this function, you must set the key with * \c mbedtls_chachapoly_setkey(). * * \param ctx The ChaCha20-Poly1305 context to use (holds the key). * \param length The length (in Bytes) of the data to decrypt. * \param nonce The \c 96 Bit (\c 12 bytes) nonce/IV to use. * \param aad The buffer containing the additional authenticated data (AAD). * This pointer can be \c NULL if `aad_len == 0`. * \param aad_len The length (in bytes) of the AAD data to process. * \param tag The buffer holding the authentication tag. * This must be a readable buffer of length \c 16 Bytes. * \param input The buffer containing the data to decrypt. * This pointer can be \c NULL if `ilen == 0`. * \param output The buffer to where the decrypted data is written. * This pointer can be \c NULL if `ilen == 0`. * * \return \c 0 on success. * \return #MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED * if the data was not authentic. * \return Another negative error code on other kinds of failure. */
int mbedtls_chachapoly_self_test( int verbose );
/** * \brief The ChaCha20-Poly1305 checkup routine. * * \return \c 0 on success. * \return \c 1 on failure. */
typedef enum
{
MBEDTLS_CHACHAPOLY_ENCRYPT, /**< The mode value for performing encryption. */
MBEDTLS_CHACHAPOLY_DECRYPT /**< The mode value for performing decryption. */
}
mbedtls_chachapoly_mode_t;
typedef struct mbedtls_chachapoly_context
{
mbedtls_chacha20_context chacha20_ctx; /**< The ChaCha20 context. */
mbedtls_poly1305_context poly1305_ctx; /**< The Poly1305 context. */
uint64_t aad_len; /**< The length (bytes) of the Additional Authenticated Data. */
uint64_t ciphertext_len; /**< The length (bytes) of the ciphertext. */
int state; /**< The current state of the context. */
mbedtls_chachapoly_mode_t mode; /**< Cipher mode (encrypt or decrypt). */
}
mbedtls_chachapoly_context;