openssl-prebuild/linux_amd64/share/doc/openssl/html/man7/provider-asym_cipher.html

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<!-- INDEX BEGIN -->
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<p><a name="__index__"></a></p>
<ul>
<li><a href="#name">NAME</a></li>
<li><a href="#synopsis">SYNOPSIS</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<ul>
<li><a href="#context_management_functions">Context Management Functions</a></li>
<li><a href="#encryption_functions">Encryption Functions</a></li>
<li><a href="#decryption_functions">Decryption Functions</a></li>
<li><a href="#asymmetric_cipher_parameters">Asymmetric Cipher Parameters</a></li>
</ul>
<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>
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<h1><a name="name">NAME</a></h1>
<p>provider-asym_cipher - The asym_cipher library &lt;-&gt; provider functions</p>
<p>
</p>
<hr />
<h1><a name="synopsis">SYNOPSIS</a></h1>
<pre>
#include &lt;openssl/core_numbers.h&gt;
#include &lt;openssl/core_names.h&gt;</pre>
<pre>
/*
* 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.
*/</pre>
<pre>
/* Context management */
void *OP_asym_cipher_newctx(void *provctx);
void OP_asym_cipher_freectx(void *ctx);
void *OP_asym_cipher_dupctx(void *ctx);</pre>
<pre>
/* Encryption */
int OP_asym_cipher_encrypt_init(void *ctx, void *provkey);
int OP_asym_cipher_encrypt(void *ctx, unsigned char *out, size_t *outlen,
size_t outsize, const unsigned char *in,
size_t inlen);</pre>
<pre>
/* Decryption */
int OP_asym_cipher_decrypt_init(void *ctx, void *provkey);
int OP_asym_cipher_decrypt(void *ctx, unsigned char *out, size_t *outlen,
size_t outsize, const unsigned char *in,
size_t inlen);</pre>
<pre>
/* Asymmetric Cipher parameters */
int OP_asym_cipher_get_ctx_params(void *ctx, OSSL_PARAM params[]);
const OSSL_PARAM *OP_asym_cipher_gettable_ctx_params(void);
int OP_asym_cipher_set_ctx_params(void *ctx, const OSSL_PARAM params[]);
const OSSL_PARAM *OP_asym_cipher_settable_ctx_params(void);</pre>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>This documentation is primarily aimed at provider authors. See <em>provider(7)</em>
for further information.</p>
<p>The asymmetric cipher (OSSL_OP_ASYM_CIPHER) operation enables providers to
implement asymmetric cipher algorithms and make them available to applications
via the API functions <em>EVP_PKEY_encrypt(3)</em>,
<em>EVP_PKEY_decrypt(3)</em> and
other related functions).</p>
<p>All &quot;functions&quot; mentioned here are passed as function pointers between
<em class="file">libcrypto</em> and the provider in <strong>OSSL_DISPATCH</strong> arrays via
<strong>OSSL_ALGORITHM</strong> arrays that are returned by the provider's
<code>provider_query_operation()</code> function
(see <em>provider-base(7)/Provider Functions</em>).</p>
<p>All these &quot;functions&quot; have a corresponding function type definition
named <strong>OSSL_{name}_fn</strong>, and a helper function to retrieve the
function pointer from an <strong>OSSL_DISPATCH</strong> element named
<strong>OSSL_get_{name}</strong>.
For example, the &quot;function&quot; <code>OP_asym_cipher_newctx()</code> has these:</p>
<pre>
typedef void *(OSSL_OP_asym_cipher_newctx_fn)(void *provctx);
static ossl_inline OSSL_OP_asym_cipher_newctx_fn
OSSL_get_OP_asym_cipher_newctx(const OSSL_DISPATCH *opf);</pre>
<p><strong>OSSL_DISPATCH</strong> arrays are indexed by numbers that are provided as
macros in <em>openssl-core_numbers.h(7)</em>, as follows:</p>
<pre>
OP_asym_cipher_newctx OSSL_FUNC_ASYM_CIPHER_NEWCTX
OP_asym_cipher_freectx OSSL_FUNC_ASYM_CIPHER_FREECTX
OP_asym_cipher_dupctx OSSL_FUNC_ASYM_CIPHER_DUPCTX</pre>
<pre>
OP_asym_cipher_encrypt_init OSSL_FUNC_ASYM_CIPHER_ENCRYPT_INIT
OP_asym_cipher_encrypt OSSL_FUNC_ASYM_CIPHER_ENCRYPT</pre>
<pre>
OP_asym_cipher_decrypt_init OSSL_FUNC_ASYM_CIPHER_DECRYPT_INIT
OP_asym_cipher_decrypt OSSL_FUNC_ASYM_CIPHER_DECRYPT</pre>
<pre>
OP_asym_cipher_get_ctx_params OSSL_FUNC_ASYM_CIPHER_GET_CTX_PARAMS
OP_asym_cipher_gettable_ctx_params OSSL_FUNC_ASYM_CIPHER_GETTABLE_CTX_PARAMS
OP_asym_cipher_set_ctx_params OSSL_FUNC_ASYM_CIPHER_SET_CTX_PARAMS
OP_asym_cipher_settable_ctx_params OSSL_FUNC_ASYM_CIPHER_SETTABLE_CTX_PARAMS</pre>
<p>An asymmetric cipher algorithm implementation may not implement all of these
functions.
In order to be a consistent set of functions a provider must implement
OP_asym_cipher_newctx and OP_asym_cipher_freectx.
It must also implement both of OP_asym_cipher_encrypt_init and
OP_asym_cipher_encrypt, or both of OP_asym_cipher_decrypt_init and
OP_asym_cipher_decrypt.
OP_asym_cipher_get_ctx_params is optional but if it is present then so must
OP_asym_cipher_gettable_ctx_params.
Similarly, OP_asym_cipher_set_ctx_params is optional but if it is present then
so must OP_asym_cipher_settable_ctx_params.</p>
<p>An asymmetric cipher algorithm must also implement some mechanism for generating,
loading or importing keys via the key management (OSSL_OP_KEYMGMT) operation.
See <em>provider-keymgmt(7)</em> for further details.</p>
<p>
</p>
<h2><a name="context_management_functions">Context Management Functions</a></h2>
<p><code>OP_asym_cipher_newctx()</code> should create and return a pointer to a provider side
structure for holding context information during an asymmetric cipher operation.
A pointer to this context will be passed back in a number of the other
asymmetric cipher operation function calls.
The parameter <em>provctx</em> is the provider context generated during provider
initialisation (see <em>provider(7)</em>).</p>
<p><code>OP_asym_cipher_freectx()</code> is passed a pointer to the provider side asymmetric
cipher context in the <em>ctx</em> parameter.
This function should free any resources associated with that context.</p>
<p><code>OP_asym_cipher_dupctx()</code> should duplicate the provider side asymmetric cipher
context in the <em>ctx</em> parameter and return the duplicate copy.</p>
<p>
</p>
<h2><a name="encryption_functions">Encryption Functions</a></h2>
<p><code>OP_asym_cipher_encrypt_init()</code> initialises a context for an asymmetric encryption
given a provider side asymmetric cipher context in the <em>ctx</em> parameter, and a
pointer to a provider key object in the <em>provkey</em> parameter.
The key object should have been previously generated, loaded or imported into
the provider using the key management (OSSL_OP_KEYMGMT) operation (see
provider-keymgmt(7)&gt;.</p>
<p><code>OP_asym_cipher_encrypt()</code> performs the actual encryption itself.
A previously initialised asymmetric cipher context is passed in the <em>ctx</em>
parameter.
The data to be encrypted is pointed to by the <em>in</em> parameter which is <em>inlen</em>
bytes long.
Unless <em>out</em> is NULL, the encrypted data should be written to the location
pointed to by the <em>out</em> parameter and it should not exceed <em>outsize</em> bytes in
length.
The length of the encrypted data should be written to <em>*outlen</em>.
If <em>out</em> is NULL then the maximum length of the encrypted data should be
written to <em>*outlen</em>.</p>
<p>
</p>
<h2><a name="decryption_functions">Decryption Functions</a></h2>
<p><code>OP_asym_cipher_decrypt_init()</code> initialises a context for an asymmetric decryption
given a provider side asymmetric cipher context in the <em>ctx</em> parameter, and a
pointer to a provider key object in the <em>provkey</em> parameter.
The key object should have been previously generated, loaded or imported into
the provider using the key management (OSSL_OP_KEYMGMT) operation (see
provider-keymgmt(7)&gt;.</p>
<p><code>OP_asym_cipher_decrypt()</code> performs the actual decryption itself.
A previously initialised asymmetric cipher context is passed in the <em>ctx</em>
parameter.
The data to be decrypted is pointed to by the <em>in</em> parameter which is <em>inlen</em>
bytes long.
Unless <em>out</em> is NULL, the decrypted data should be written to the location
pointed to by the <em>out</em> parameter and it should not exceed <em>outsize</em> bytes in
length.
The length of the decrypted data should be written to <em>*outlen</em>.
If <em>out</em> is NULL then the maximum length of the decrypted data should be
written to <em>*outlen</em>.</p>
<p>
</p>
<h2><a name="asymmetric_cipher_parameters">Asymmetric Cipher Parameters</a></h2>
<p>See <em>OSSL_PARAM(3)</em> for further details on the parameters structure used by
the <code>OP_asym_cipher_get_ctx_params()</code> and <code>OP_asym_cipher_set_ctx_params()</code>
functions.</p>
<p><code>OP_asym_cipher_get_ctx_params()</code> gets asymmetric cipher parameters associated
with the given provider side asymmetric cipher context <em>ctx</em> and stores them in
<em>params</em>.
<code>OP_asym_cipher_set_ctx_params()</code> sets the asymmetric cipher parameters associated
with the given provider side asymmetric cipher context <em>ctx</em> to <em>params</em>.
Any parameter settings are additional to any that were previously set.</p>
<p>Parameters currently recognised by built-in asymmetric cipher algorithms are as
follows.
Not all parameters are relevant to, or are understood by all asymmetric cipher
algorithms:</p>
<dl>
<dt><strong><a name="pad_mode_ossl_asym_cipher_param_pad_mode_integer" class="item">&quot;pad-mode&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_PAD_MODE</strong>) &lt;integer&gt;</a></strong></dt>
<dd>
<p>The type of padding to be used. The interpretation of this value will depend
on the algorithm in use. The default provider understands these RSA padding
modes: 1 (RSA_PKCS1_PADDING), 2 (RSA_SSLV23_PADDING), 3 (RSA_NO_PADDING),
4 (RSA_PKCS1_OAEP_PADDING), 5 (RSA_X931_PADDING), 6 (RSA_PKCS1_PSS_PADDING) and
7 (RSA_PKCS1_WITH_TLS_PADDING). See <em>EVP_PKEY_CTX_set_rsa_padding(3)</em> for
further details.</p>
</dd>
<dt><strong><a name="digest_ossl_asym_cipher_param_oaep_digest_utf8_string" class="item">&quot;digest&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dd>
<p>Gets or sets the name of the OAEP digest algorithm used when OAEP padding is in
use.</p>
</dd>
<dt><strong><a name="digest_props_ossl_asym_cipher_param_oaep_digest_props_utf8_string" class="item">&quot;digest-props&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_OAEP_DIGEST_PROPS</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dd>
<p>Gets or sets the properties to use when fetching the OAEP digest algorithm.</p>
</dd>
<dt><strong><a name="mgf1_digest_ossl_asym_cipher_param_mgf1_digest_utf8_string" class="item">&quot;mgf1-digest&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dd>
<p>Gets or sets the name of the MGF1 digest algorithm used when OAEP or PSS padding
is in use.</p>
</dd>
<dt><strong><a name="mgf1_digest_props_ossl_asym_cipher_param_mgf1_digest_props_utf8_string" class="item">&quot;mgf1-digest-props&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_MGF1_DIGEST_PROPS</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dd>
<p>Gets or sets the properties to use when fetching the MGF1 digest algorithm.</p>
</dd>
<dt><strong><a name="oaep_label_ossl_asym_cipher_param_oaep_label_octet_string" class="item">&quot;oaep-label&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL</strong>) &lt;octet string&gt;</a></strong></dt>
<dd>
<p>Gets or sets the OAEP label used when OAEP padding is in use.</p>
</dd>
<dt><strong><a name="oaep_label_len_ossl_asym_cipher_param_oaep_label_len_size_t" class="item">&quot;oaep-label-len&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_OAEP_LABEL_LEN</strong>) &lt;size_t&gt;</a></strong></dt>
<dd>
<p>Gets the length of an OAEP label when OAEP padding is in use.</p>
</dd>
<dt><strong><a name="tls_client_version_ossl_asym_cipher_param_tls_client_version_unsigned_integer" class="item">&quot;tls-client-version&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION</strong>) &lt;unsigned integer&gt;</a></strong></dt>
<dd>
<p>The TLS protocol version first requested by the client. See
<strong>RSA_PKCS1_WITH_TLS_PADDING</strong> on the page <em>EVP_PKEY_CTX_set_rsa_padding(3)</em>.</p>
</dd>
<dt><strong><a name="tls_negotiated_version_ossl_asym_cipher_param_tls_client_version_unsigned_integer" class="item">&quot;tls-negotiated-version&quot; (<strong>OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION</strong>) &lt;unsigned integer&gt;</a></strong></dt>
<dd>
<p>The negotiated TLS protocol version. See
<strong>RSA_PKCS1_WITH_TLS_PADDING</strong> on the page <em>EVP_PKEY_CTX_set_rsa_padding(3)</em>.</p>
</dd>
</dl>
<p><code>OP_asym_cipher_gettable_ctx_params()</code> and <code>OP_asym_cipher_settable_ctx_params()</code>
get a constant <strong>OSSL_PARAM</strong> array that describes the gettable and settable
parameters, i.e. parameters that can be used with <code>OP_asym_cipherget_ctx_params()</code>
and <code>OP_asym_cipher_set_ctx_params()</code> respectively.
See <em>OSSL_PARAM(3)</em> for the use of <strong>OSSL_PARAM</strong> as parameter descriptor.</p>
<p>
</p>
<hr />
<h1><a name="return_values">RETURN VALUES</a></h1>
<p><code>OP_asym_cipher_newctx()</code> and <code>OP_asym_cipher_dupctx()</code> should return the newly
created provider side asymmetric cipher context, or NULL on failure.</p>
<p>All other functions should return 1 for success or 0 on error.</p>
<p>
</p>
<hr />
<h1><a name="see_also">SEE ALSO</a></h1>
<p><em>provider(7)</em></p>
<p>
</p>
<hr />
<h1><a name="history">HISTORY</a></h1>
<p>The provider ASYM_CIPHER interface was introduced in OpenSSL 3.0.</p>
<p>
</p>
<hr />
<h1><a name="copyright">COPYRIGHT</a></h1>
<p>Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.</p>
<p>Licensed under the Apache License 2.0 (the &quot;License&quot;). 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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