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<ul id="index">
<li><a href="#NAME">NAME</a></li>
<li><a href="#SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#Context-Management-Functions">Context Management Functions</a></li>
<li><a href="#Encryption-Decryption-Functions">Encryption/Decryption Functions</a></li>
<li><a href="#Cipher-Parameters">Cipher Parameters</a></li>
</ul>
</li>
<li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
<li><a href="#SEE-ALSO">SEE ALSO</a></li>
<li><a href="#HISTORY">HISTORY</a></li>
<li><a href="#COPYRIGHT">COPYRIGHT</a></li>
</ul>
<h1 id="NAME">NAME</h1>
<p>provider-cipher - The cipher library <-> provider functions</p>
<h1 id="SYNOPSIS">SYNOPSIS</h1>
<pre><code> #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[]);</code></pre>
<h1 id="DESCRIPTION">DESCRIPTION</h1>
<p>This documentation is primarily aimed at provider authors. See <a href="../man7/provider.html">provider(7)</a> for further information.</p>
<p>The CIPHER operation enables providers to implement cipher algorithms and make them available to applications via the API functions <a href="../man3/EVP_EncryptInit_ex.html">EVP_EncryptInit_ex(3)</a>, <a href="../man3/EVP_EncryptUpdate.html">EVP_EncryptUpdate(3)</a> and <a href="../man3/EVP_EncryptFinal.html">EVP_EncryptFinal(3)</a> (as well as the decrypt equivalents and other related functions).</p>
<p>All "functions" mentioned here are passed as function pointers between <i>libcrypto</i> and the provider in <b>OSSL_DISPATCH</b> arrays via <b>OSSL_ALGORITHM</b> arrays that are returned by the provider's provider_query_operation() function (see <a href="../man7/provider-base.html">"Provider Functions" in provider-base(7)</a>).</p>
<p>All these "functions" have a corresponding function type definition named <b>OSSL_FUNC_{name}_fn</b>, and a helper function to retrieve the function pointer from an <b>OSSL_DISPATCH</b> element named <b>OSSL_FUNC_{name}</b>. For example, the "function" OSSL_FUNC_cipher_newctx() has these:</p>
<pre><code> 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);</code></pre>
<p><b>OSSL_DISPATCH</b> arrays are indexed by numbers that are provided as macros in <a href="../man7/openssl-core_dispatch.h.html">openssl-core_dispatch.h(7)</a>, as follows:</p>
<pre><code> 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</code></pre>
<p>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.</p>
<h2 id="Context-Management-Functions">Context Management Functions</h2>
<p>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 <i>provctx</i> is the provider context generated during provider initialisation (see <a href="../man7/provider.html">provider(7)</a>).</p>
<p>OSSL_FUNC_cipher_freectx() is passed a pointer to the provider side cipher context in the <i>cctx</i> parameter. This function should free any resources associated with that context.</p>
<p>OSSL_FUNC_cipher_dupctx() should duplicate the provider side cipher context in the <i>cctx</i> parameter and return the duplicate copy.</p>
<h2 id="Encryption-Decryption-Functions">Encryption/Decryption Functions</h2>
<p>OSSL_FUNC_cipher_encrypt_init() initialises a cipher operation for encryption given a newly created provider side cipher context in the <i>cctx</i> parameter. The key to be used is given in <i>key</i> which is <i>keylen</i> bytes long. The IV to be used is given in <i>iv</i> which is <i>ivlen</i> bytes long. The <i>params</i>, if not NULL, should be set on the context in a manner similar to using OSSL_FUNC_cipher_set_ctx_params().</p>
<p>OSSL_FUNC_cipher_decrypt_init() is the same as OSSL_FUNC_cipher_encrypt_init() except that it initialises the context for a decryption operation.</p>
<p>OSSL_FUNC_cipher_update() is called to supply data to be encrypted/decrypted as part of a previously initialised cipher operation. The <i>cctx</i> parameter contains a pointer to a previously initialised provider side context. OSSL_FUNC_cipher_update() should encrypt/decrypt <i>inl</i> bytes of data at the location pointed to by <i>in</i>. The encrypted data should be stored in <i>out</i> and the amount of data written to <i>*outl</i> which should not exceed <i>outsize</i> 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. <i>out</i> may be the same location as <i>in</i> but it should not partially overlap. The same expectations apply to <i>outsize</i> as documented for <a href="../man3/EVP_EncryptUpdate.html">EVP_EncryptUpdate(3)</a> and <a href="../man3/EVP_DecryptUpdate.html">EVP_DecryptUpdate(3)</a>.</p>
<p>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 <i>cctx</i> parameter contains a pointer to the provider side context. Any final encryption/decryption output should be written to <i>out</i> and the amount of data written to <i>*outl</i> which should not exceed <i>outsize</i> bytes. The same expectations apply to <i>outsize</i> as documented for <a href="../man3/EVP_EncryptFinal.html">EVP_EncryptFinal(3)</a> and <a href="../man3/EVP_DecryptFinal.html">EVP_DecryptFinal(3)</a>.</p>
<p>OSSL_FUNC_cipher_cipher() performs encryption/decryption using the provider side cipher context in the <i>cctx</i> 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 <a href="../man3/EVP_Cipher.html">EVP_Cipher(3)</a>. 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 <i>in</i>, and it will be <i>inl</i> bytes in length. The output from the encryption/decryption should be stored in <i>out</i> and the amount of data stored should be put in <i>*outl</i> which should be no more than <i>outsize</i> bytes.</p>
<h2 id="Cipher-Parameters">Cipher Parameters</h2>
<p>See <a href="../man3/OSSL_PARAM.html">OSSL_PARAM(3)</a> for further details on the parameters structure used by these functions.</p>
<p>OSSL_FUNC_cipher_get_params() gets details of the algorithm implementation and stores them in <i>params</i>.</p>
<p>OSSL_FUNC_cipher_set_ctx_params() sets cipher operation parameters for the provider side cipher context <i>cctx</i> to <i>params</i>. Any parameter settings are additional to any that were previously set. Passing NULL for <i>params</i> should return true.</p>
<p>OSSL_FUNC_cipher_get_ctx_params() gets cipher operation details details from the given provider side cipher context <i>cctx</i> and stores them in <i>params</i>. Passing NULL for <i>params</i> should return true.</p>
<p>OSSL_FUNC_cipher_gettable_params(), OSSL_FUNC_cipher_gettable_ctx_params(), and OSSL_FUNC_cipher_settable_ctx_params() all return constant <b>OSSL_PARAM</b> 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 <i>cctx</i> in its current state if it is not NULL. Otherwise, they return the parameters associated with the provider side algorithm <i>provctx</i>.</p>
<p>Parameters currently recognised by built-in ciphers are listed in <a href="../man3/EVP_EncryptInit.html">"PARAMETERS" in EVP_EncryptInit(3)</a>. Not all parameters are relevant to, or are understood by all ciphers.</p>
<h1 id="RETURN-VALUES">RETURN VALUES</h1>
<p>OSSL_FUNC_cipher_newctx() and OSSL_FUNC_cipher_dupctx() should return the newly created provider side cipher context, or NULL on failure.</p>
<p>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.</p>
<p>OSSL_FUNC_cipher_gettable_params(), OSSL_FUNC_cipher_gettable_ctx_params() and OSSL_FUNC_cipher_settable_ctx_params() should return a constant <b>OSSL_PARAM</b> array, or NULL if none is offered.</p>
<h1 id="SEE-ALSO">SEE ALSO</h1>
<p><a href="../man7/provider.html">provider(7)</a>, <a href="../man7/OSSL_PROVIDER-FIPS.html">OSSL_PROVIDER-FIPS(7)</a>, <a href="../man7/OSSL_PROVIDER-default.html">OSSL_PROVIDER-default(7)</a>, <a href="../man7/OSSL_PROVIDER-legacy.html">OSSL_PROVIDER-legacy(7)</a>, <a href="../man7/EVP_CIPHER-AES.html">EVP_CIPHER-AES(7)</a>, <a href="../man7/EVP_CIPHER-ARIA.html">EVP_CIPHER-ARIA(7)</a>, <a href="../man7/EVP_CIPHER-BLOWFISH.html">EVP_CIPHER-BLOWFISH(7)</a>, <a href="../man7/EVP_CIPHER-CAMELLIA.html">EVP_CIPHER-CAMELLIA(7)</a>, <a href="../man7/EVP_CIPHER-CAST.html">EVP_CIPHER-CAST(7)</a>, <a href="../man7/EVP_CIPHER-CHACHA.html">EVP_CIPHER-CHACHA(7)</a>, <a href="../man7/EVP_CIPHER-DES.html">EVP_CIPHER-DES(7)</a>, <a href="../man7/EVP_CIPHER-IDEA.html">EVP_CIPHER-IDEA(7)</a>, <a href="../man7/EVP_CIPHER-RC2.html">EVP_CIPHER-RC2(7)</a>, <a href="../man7/EVP_CIPHER-RC4.html">EVP_CIPHER-RC4(7)</a>, <a href="../man7/EVP_CIPHER-RC5.html">EVP_CIPHER-RC5(7)</a>, <a href="../man7/EVP_CIPHER-SEED.html">EVP_CIPHER-SEED(7)</a>, <a href="../man7/EVP_CIPHER-SM4.html">EVP_CIPHER-SM4(7)</a>, <a href="../man7/life_cycle-cipher.html">life_cycle-cipher(7)</a>, <a href="../man3/EVP_EncryptInit.html">EVP_EncryptInit(3)</a></p>
<h1 id="HISTORY">HISTORY</h1>
<p>The provider CIPHER interface was introduced in OpenSSL 3.0.</p>
<h1 id="COPYRIGHT">COPYRIGHT</h1>
<p>Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.</p>
<p>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 <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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