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PROVIDER-CIPHER(7ossl)               OpenSSL              PROVIDER-CIPHER(7ossl)


       provider-cipher - The cipher library <-> provider functions


        #include <openssl/core_dispatch.h>
        #include <openssl/core_names.h>

         * None of these are actual functions, but are displayed like this for
         * the function signatures for functions that are offered as function
         * pointers in OSSL_DISPATCH arrays.

        /* Context management */
        void *OSSL_FUNC_cipher_newctx(void *provctx);
        void OSSL_FUNC_cipher_freectx(void *cctx);
        void *OSSL_FUNC_cipher_dupctx(void *cctx);

        /* Encryption/decryption */
        int OSSL_FUNC_cipher_encrypt_init(void *cctx, const unsigned char *key,
                                          size_t keylen, const unsigned char *iv,
                                          size_t ivlen, const OSSL_PARAM params[]);
        int OSSL_FUNC_cipher_decrypt_init(void *cctx, const unsigned char *key,
                                          size_t keylen, const unsigned char *iv,
                                          size_t ivlen, const OSSL_PARAM params[]);
        int OSSL_FUNC_cipher_update(void *cctx, unsigned char *out, size_t *outl,
                                    size_t outsize, const unsigned char *in, size_t inl);
        int OSSL_FUNC_cipher_final(void *cctx, unsigned char *out, size_t *outl,
                                   size_t outsize);
        int OSSL_FUNC_cipher_cipher(void *cctx, unsigned char *out, size_t *outl,
                                    size_t outsize, const unsigned char *in, size_t inl);

        /* Cipher parameter descriptors */
        const OSSL_PARAM *OSSL_FUNC_cipher_gettable_params(void *provctx);

        /* Cipher operation parameter descriptors */
        const OSSL_PARAM *OSSL_FUNC_cipher_gettable_ctx_params(void *cctx,
                                                               void *provctx);
        const OSSL_PARAM *OSSL_FUNC_cipher_settable_ctx_params(void *cctx,
                                                               void *provctx);

        /* Cipher parameters */
        int OSSL_FUNC_cipher_get_params(OSSL_PARAM params[]);

        /* Cipher operation parameters */
        int OSSL_FUNC_cipher_get_ctx_params(void *cctx, OSSL_PARAM params[]);
        int OSSL_FUNC_cipher_set_ctx_params(void *cctx, const OSSL_PARAM params[]);


       This documentation is primarily aimed at provider authors. See
       provider(7) for further information.

       The CIPHER operation enables providers to implement cipher algorithms and
       make them available to applications via the API functions
       EVP_EncryptInit_ex(3), EVP_EncryptUpdate(3) and EVP_EncryptFinal(3) (as
       well as the decrypt equivalents and other related functions).

       All "functions" mentioned here are passed as function pointers between
       libcrypto and the provider in OSSL_DISPATCH(3) arrays via
       OSSL_ALGORITHM(3) arrays that are returned by the provider's
       provider_query_operation() function (see "Provider Functions" in

       All these "functions" have a corresponding function type definition named
       OSSL_FUNC_{name}_fn, and a helper function to retrieve the function
       pointer from an OSSL_DISPATCH(3) element named OSSL_FUNC_{name}.  For
       example, the "function" OSSL_FUNC_cipher_newctx() has these:

        typedef void *(OSSL_FUNC_cipher_newctx_fn)(void *provctx);
        static ossl_inline OSSL_FUNC_cipher_newctx_fn
            OSSL_FUNC_cipher_newctx(const OSSL_DISPATCH *opf);

       OSSL_DISPATCH(3) arrays are indexed by numbers that are provided as
       macros in openssl-core_dispatch.h(7), as follows:

        OSSL_FUNC_cipher_newctx               OSSL_FUNC_CIPHER_NEWCTX
        OSSL_FUNC_cipher_freectx              OSSL_FUNC_CIPHER_FREECTX
        OSSL_FUNC_cipher_dupctx               OSSL_FUNC_CIPHER_DUPCTX

        OSSL_FUNC_cipher_encrypt_init         OSSL_FUNC_CIPHER_ENCRYPT_INIT
        OSSL_FUNC_cipher_decrypt_init         OSSL_FUNC_CIPHER_DECRYPT_INIT
        OSSL_FUNC_cipher_update               OSSL_FUNC_CIPHER_UPDATE
        OSSL_FUNC_cipher_final                OSSL_FUNC_CIPHER_FINAL
        OSSL_FUNC_cipher_cipher               OSSL_FUNC_CIPHER_CIPHER

        OSSL_FUNC_cipher_get_params           OSSL_FUNC_CIPHER_GET_PARAMS
        OSSL_FUNC_cipher_get_ctx_params       OSSL_FUNC_CIPHER_GET_CTX_PARAMS
        OSSL_FUNC_cipher_set_ctx_params       OSSL_FUNC_CIPHER_SET_CTX_PARAMS

        OSSL_FUNC_cipher_gettable_params      OSSL_FUNC_CIPHER_GETTABLE_PARAMS
        OSSL_FUNC_cipher_gettable_ctx_params  OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS
        OSSL_FUNC_cipher_settable_ctx_params  OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS

       A cipher algorithm implementation may not implement all of these
       functions.  In order to be a consistent set of functions there must at
       least be a complete set of "encrypt" functions, or a complete set of
       "decrypt" functions, or a single "cipher" function.  In all cases both
       the OSSL_FUNC_cipher_newctx and OSSL_FUNC_cipher_freectx functions must
       be present.  All other functions are optional.

   Context Management Functions
       OSSL_FUNC_cipher_newctx() should create and return a pointer to a
       provider side structure for holding context information during a cipher
       operation.  A pointer to this context will be passed back in a number of
       the other cipher operation function calls.  The parameter provctx is the
       provider context generated during provider initialisation (see

       OSSL_FUNC_cipher_freectx() is passed a pointer to the provider side
       cipher context in the cctx parameter.  This function should free any
       resources associated with that context.

       OSSL_FUNC_cipher_dupctx() should duplicate the provider side cipher
       context in the cctx parameter and return the duplicate copy.

   Encryption/Decryption Functions
       OSSL_FUNC_cipher_encrypt_init() initialises a cipher operation for
       encryption given a newly created provider side cipher context in the cctx
       parameter.  The key to be used is given in key which is keylen bytes
       long.  The IV to be used is given in iv which is ivlen bytes long.  The
       params, if not NULL, should be set on the context in a manner similar to
       using OSSL_FUNC_cipher_set_ctx_params().

       OSSL_FUNC_cipher_decrypt_init() is the same as
       OSSL_FUNC_cipher_encrypt_init() except that it initialises the context
       for a decryption operation.

       OSSL_FUNC_cipher_update() is called to supply data to be
       encrypted/decrypted as part of a previously initialised cipher operation.
       The cctx parameter contains a pointer to a previously initialised
       provider side context.  OSSL_FUNC_cipher_update() should encrypt/decrypt
       inl bytes of data at the location pointed to by in.  The encrypted data
       should be stored in out and the amount of data written to *outl which
       should not exceed outsize bytes.  OSSL_FUNC_cipher_update() may be called
       multiple times for a single cipher operation.  It is the responsibility
       of the cipher implementation to handle input lengths that are not
       multiples of the block length.  In such cases a cipher implementation
       will typically cache partial blocks of input data until a complete block
       is obtained.  out may be the same location as in but it should not
       partially overlap.  The same expectations apply to outsize as documented
       for EVP_EncryptUpdate(3) and EVP_DecryptUpdate(3).

       OSSL_FUNC_cipher_final() completes an encryption or decryption started
       through previous OSSL_FUNC_cipher_encrypt_init() or
       OSSL_FUNC_cipher_decrypt_init(), and OSSL_FUNC_cipher_update() calls.
       The cctx parameter contains a pointer to the provider side context.  Any
       final encryption/decryption output should be written to out and the
       amount of data written to *outl which should not exceed outsize bytes.
       The same expectations apply to outsize as documented for
       EVP_EncryptFinal(3) and EVP_DecryptFinal(3).

       OSSL_FUNC_cipher_cipher() performs encryption/decryption using the
       provider side cipher context in the cctx parameter that should have been
       previously initialised via a call to OSSL_FUNC_cipher_encrypt_init() or
       OSSL_FUNC_cipher_decrypt_init().  This should call the raw underlying
       cipher function without any padding.  This will be invoked in the
       provider as a result of the application calling EVP_Cipher(3).  The
       application is responsible for ensuring that the input is a multiple of
       the block length.  The data to be encrypted/decrypted will be in in, and
       it will be inl bytes in length.  The output from the
       encryption/decryption should be stored in out and the amount of data
       stored should be put in *outl which should be no more than outsize bytes.

   Cipher Parameters
       See OSSL_PARAM(3) for further details on the parameters structure used by
       these functions.

       OSSL_FUNC_cipher_get_params() gets details of the algorithm
       implementation and stores them in params.

       OSSL_FUNC_cipher_set_ctx_params() sets cipher operation parameters for
       the provider side cipher context cctx to params.  Any parameter settings
       are additional to any that were previously set.  Passing NULL for params
       should return true.

       OSSL_FUNC_cipher_get_ctx_params() gets cipher operation details details
       from the given provider side cipher context cctx and stores them in
       params.  Passing NULL for params should return true.

       OSSL_FUNC_cipher_gettable_ctx_params(), and
       OSSL_FUNC_cipher_settable_ctx_params() all return constant OSSL_PARAM(3)
       arrays as descriptors of the parameters that
       OSSL_FUNC_cipher_get_params(), OSSL_FUNC_cipher_get_ctx_params(), and
       OSSL_FUNC_cipher_set_ctx_params() can handle, respectively.
       OSSL_FUNC_cipher_gettable_ctx_params() and
       OSSL_FUNC_cipher_settable_ctx_params() will return the parameters
       associated with the provider side context cctx in its current state if it
       is not NULL.  Otherwise, they return the parameters associated with the
       provider side algorithm provctx.

       Parameters currently recognised by built-in ciphers are listed in
       "PARAMETERS" in EVP_EncryptInit(3).  Not all parameters are relevant to,
       or are understood by all ciphers.


       OSSL_FUNC_cipher_newctx() and OSSL_FUNC_cipher_dupctx() should return the
       newly created provider side cipher context, or NULL on failure.

       OSSL_FUNC_cipher_encrypt_init(), OSSL_FUNC_cipher_decrypt_init(),
       OSSL_FUNC_cipher_update(), OSSL_FUNC_cipher_final(),
       OSSL_FUNC_cipher_cipher(), OSSL_FUNC_cipher_get_params(),
       OSSL_FUNC_cipher_get_ctx_params() and OSSL_FUNC_cipher_set_ctx_params()
       should return 1 for success or 0 on error.

       OSSL_FUNC_cipher_gettable_ctx_params() and
       OSSL_FUNC_cipher_settable_ctx_params() should return a constant
       OSSL_PARAM(3) array, or NULL if none is offered.


       provider(7), OSSL_PROVIDER-FIPS(7), OSSL_PROVIDER-default(7),
       life_cycle-cipher(7), EVP_EncryptInit(3)


       The provider CIPHER interface was introduced in OpenSSL 3.0.


       Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

3.1.0                              2023-03-14             PROVIDER-CIPHER(7ossl)

openssl 3.1.0 - Generated Wed Mar 15 08:25:33 CDT 2023
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