^^&&^^

Edit File: EVP_PKEY_meth_get_paramgen.html

<?xml version="1.0" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>EVP_PKEY_meth_new</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<link rev="made" href="mailto:root@localhost" />
</head>

<body>

<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="#Methods">Methods</a></li>
 <li><a href="#Functions">Functions</a></li>
 </ul>
 </li>
 <li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
 <li><a href="#COPYRIGHT">COPYRIGHT</a></li>
</ul>

EVP_PKEY_meth_new, EVP_PKEY_meth_free, EVP_PKEY_meth_copy, EVP_PKEY_meth_find, EVP_PKEY_meth_add0, EVP_PKEY_METHOD, EVP_PKEY_meth_set_init, EVP_PKEY_meth_set_copy, EVP_PKEY_meth_set_cleanup, EVP_PKEY_meth_set_paramgen, EVP_PKEY_meth_set_keygen, EVP_PKEY_meth_set_sign, EVP_PKEY_meth_set_verify, EVP_PKEY_meth_set_verify_recover, EVP_PKEY_meth_set_signctx, EVP_PKEY_meth_set_verifyctx, EVP_PKEY_meth_set_encrypt, EVP_PKEY_meth_set_decrypt, EVP_PKEY_meth_set_derive, EVP_PKEY_meth_set_ctrl, EVP_PKEY_meth_set_digestsign, EVP_PKEY_meth_set_digestverify, EVP_PKEY_meth_set_check, EVP_PKEY_meth_set_public_check, EVP_PKEY_meth_set_param_check, EVP_PKEY_meth_set_digest_custom, EVP_PKEY_meth_get_init, EVP_PKEY_meth_get_copy, EVP_PKEY_meth_get_cleanup, EVP_PKEY_meth_get_paramgen, EVP_PKEY_meth_get_keygen, EVP_PKEY_meth_get_sign, EVP_PKEY_meth_get_verify, EVP_PKEY_meth_get_verify_recover, EVP_PKEY_meth_get_signctx, EVP_PKEY_meth_get_verifyctx, EVP_PKEY_meth_get_encrypt, EVP_PKEY_meth_get_decrypt, EVP_PKEY_meth_get_derive, EVP_PKEY_meth_get_ctrl, EVP_PKEY_meth_get_digestsign, EVP_PKEY_meth_get_digestverify, EVP_PKEY_meth_get_check, EVP_PKEY_meth_get_public_check, EVP_PKEY_meth_get_param_check, EVP_PKEY_meth_get_digest_custom, EVP_PKEY_meth_remove - manipulating EVP_PKEY_METHOD structure

<h1 id="SYNOPSIS">SYNOPSIS</h1>

<pre><code> #include &lt;openssl/evp.h&gt;

typedef struct evp_pkey_method_st EVP_PKEY_METHOD;

EVP_PKEY_METHOD *EVP_PKEY_meth_new(int id, int flags);
 void EVP_PKEY_meth_free(EVP_PKEY_METHOD *pmeth);
 void EVP_PKEY_meth_copy(EVP_PKEY_METHOD *dst, const EVP_PKEY_METHOD *src);
 const EVP_PKEY_METHOD *EVP_PKEY_meth_find(int type);
 int EVP_PKEY_meth_add0(const EVP_PKEY_METHOD *pmeth);
 int EVP_PKEY_meth_remove(const EVP_PKEY_METHOD *pmeth);

void EVP_PKEY_meth_set_init(EVP_PKEY_METHOD *pmeth,
                             int (*init) (EVP_PKEY_CTX *ctx));
 void EVP_PKEY_meth_set_copy(EVP_PKEY_METHOD *pmeth,
                             int (*copy) (EVP_PKEY_CTX *dst,
                                          EVP_PKEY_CTX *src));
 void EVP_PKEY_meth_set_cleanup(EVP_PKEY_METHOD *pmeth,
                                void (*cleanup) (EVP_PKEY_CTX *ctx));
 void EVP_PKEY_meth_set_paramgen(EVP_PKEY_METHOD *pmeth,
                                 int (*paramgen_init) (EVP_PKEY_CTX *ctx),
                                 int (*paramgen) (EVP_PKEY_CTX *ctx,
                                                  EVP_PKEY *pkey));
 void EVP_PKEY_meth_set_keygen(EVP_PKEY_METHOD *pmeth,
                               int (*keygen_init) (EVP_PKEY_CTX *ctx),
                               int (*keygen) (EVP_PKEY_CTX *ctx,
                                              EVP_PKEY *pkey));
 void EVP_PKEY_meth_set_sign(EVP_PKEY_METHOD *pmeth,
                             int (*sign_init) (EVP_PKEY_CTX *ctx),
                             int (*sign) (EVP_PKEY_CTX *ctx,
                                          unsigned char *sig, size_t *siglen,
                                          const unsigned char *tbs,
                                          size_t tbslen));
 void EVP_PKEY_meth_set_verify(EVP_PKEY_METHOD *pmeth,
                               int (*verify_init) (EVP_PKEY_CTX *ctx),
                               int (*verify) (EVP_PKEY_CTX *ctx,
                                              const unsigned char *sig,
                                              size_t siglen,
                                              const unsigned char *tbs,
                                              size_t tbslen));
 void EVP_PKEY_meth_set_verify_recover(EVP_PKEY_METHOD *pmeth,
                                       int (*verify_recover_init) (EVP_PKEY_CTX
                                                                   *ctx),
                                       int (*verify_recover) (EVP_PKEY_CTX
                                                              *ctx,
                                                              unsigned char
                                                              *sig,
                                                              size_t *siglen,
                                                              const unsigned
                                                              char *tbs,
                                                              size_t tbslen));
 void EVP_PKEY_meth_set_signctx(EVP_PKEY_METHOD *pmeth,
                                int (*signctx_init) (EVP_PKEY_CTX *ctx,
                                                     EVP_MD_CTX *mctx),
                                int (*signctx) (EVP_PKEY_CTX *ctx,
                                                unsigned char *sig,
                                                size_t *siglen,
                                                EVP_MD_CTX *mctx));
 void EVP_PKEY_meth_set_verifyctx(EVP_PKEY_METHOD *pmeth,
                                  int (*verifyctx_init) (EVP_PKEY_CTX *ctx,
                                                         EVP_MD_CTX *mctx),
                                  int (*verifyctx) (EVP_PKEY_CTX *ctx,
                                                    const unsigned char *sig,
                                                    int siglen,
                                                    EVP_MD_CTX *mctx));
 void EVP_PKEY_meth_set_encrypt(EVP_PKEY_METHOD *pmeth,
                                int (*encrypt_init) (EVP_PKEY_CTX *ctx),
                                int (*encryptfn) (EVP_PKEY_CTX *ctx,
                                                  unsigned char *out,
                                                  size_t *outlen,
                                                  const unsigned char *in,
                                                  size_t inlen));
 void EVP_PKEY_meth_set_decrypt(EVP_PKEY_METHOD *pmeth,
                                int (*decrypt_init) (EVP_PKEY_CTX *ctx),
                                int (*decrypt) (EVP_PKEY_CTX *ctx,
                                                unsigned char *out,
                                                size_t *outlen,
                                                const unsigned char *in,
                                                size_t inlen));
 void EVP_PKEY_meth_set_derive(EVP_PKEY_METHOD *pmeth,
                               int (*derive_init) (EVP_PKEY_CTX *ctx),
                               int (*derive) (EVP_PKEY_CTX *ctx,
                                              unsigned char *key,
                                              size_t *keylen));
 void EVP_PKEY_meth_set_ctrl(EVP_PKEY_METHOD *pmeth,
                             int (*ctrl) (EVP_PKEY_CTX *ctx, int type, int p1,
                                          void *p2),
                             int (*ctrl_str) (EVP_PKEY_CTX *ctx,
                                              const char *type,
                                              const char *value));
 void EVP_PKEY_meth_set_digestsign(EVP_PKEY_METHOD *pmeth,
                                   int (*digestsign) (EVP_MD_CTX *ctx,
                                                      unsigned char *sig,
                                                      size_t *siglen,
                                                      const unsigned char *tbs,
                                                      size_t tbslen));
 void EVP_PKEY_meth_set_digestverify(EVP_PKEY_METHOD *pmeth,
                                     int (*digestverify) (EVP_MD_CTX *ctx,
                                                          const unsigned char *sig,
                                                          size_t siglen,
                                                          const unsigned char *tbs,
                                                          size_t tbslen));
 void EVP_PKEY_meth_set_check(EVP_PKEY_METHOD *pmeth,
                              int (*check) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_set_public_check(EVP_PKEY_METHOD *pmeth,
                                     int (*check) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_set_param_check(EVP_PKEY_METHOD *pmeth,
                                    int (*check) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_set_digest_custom(EVP_PKEY_METHOD *pmeth,
                                     int (*digest_custom) (EVP_PKEY_CTX *ctx,
                                                           EVP_MD_CTX *mctx));

void EVP_PKEY_meth_get_init(const EVP_PKEY_METHOD *pmeth,
 int (**pinit) (EVP_PKEY_CTX *ctx));
 void EVP_PKEY_meth_get_copy(const EVP_PKEY_METHOD *pmeth,
 int (**pcopy) (EVP_PKEY_CTX *dst,
 EVP_PKEY_CTX *src));
 void EVP_PKEY_meth_get_cleanup(const EVP_PKEY_METHOD *pmeth,
 void (**pcleanup) (EVP_PKEY_CTX *ctx));
 void EVP_PKEY_meth_get_paramgen(const EVP_PKEY_METHOD *pmeth,
 int (**pparamgen_init) (EVP_PKEY_CTX *ctx),
 int (**pparamgen) (EVP_PKEY_CTX *ctx,
 EVP_PKEY *pkey));
 void EVP_PKEY_meth_get_keygen(const EVP_PKEY_METHOD *pmeth,
 int (**pkeygen_init) (EVP_PKEY_CTX *ctx),
 int (**pkeygen) (EVP_PKEY_CTX *ctx,
 EVP_PKEY *pkey));
 void EVP_PKEY_meth_get_sign(const EVP_PKEY_METHOD *pmeth,
 int (**psign_init) (EVP_PKEY_CTX *ctx),
 int (**psign) (EVP_PKEY_CTX *ctx,
 unsigned char *sig, size_t *siglen,
 const unsigned char *tbs,
 size_t tbslen));
 void EVP_PKEY_meth_get_verify(const EVP_PKEY_METHOD *pmeth,
 int (**pverify_init) (EVP_PKEY_CTX *ctx),
 int (**pverify) (EVP_PKEY_CTX *ctx,
 const unsigned char *sig,
 size_t siglen,
 const unsigned char *tbs,
 size_t tbslen));
 void EVP_PKEY_meth_get_verify_recover(const EVP_PKEY_METHOD *pmeth,
 int (**pverify_recover_init) (EVP_PKEY_CTX
 *ctx),
 int (**pverify_recover) (EVP_PKEY_CTX
 *ctx,
 unsigned char
 *sig,
 size_t *siglen,
 const unsigned
 char *tbs,
 size_t tbslen));
 void EVP_PKEY_meth_get_signctx(const EVP_PKEY_METHOD *pmeth,
 int (**psignctx_init) (EVP_PKEY_CTX *ctx,
 EVP_MD_CTX *mctx),
 int (**psignctx) (EVP_PKEY_CTX *ctx,
 unsigned char *sig,
 size_t *siglen,
 EVP_MD_CTX *mctx));
 void EVP_PKEY_meth_get_verifyctx(const EVP_PKEY_METHOD *pmeth,
 int (**pverifyctx_init) (EVP_PKEY_CTX *ctx,
 EVP_MD_CTX *mctx),
 int (**pverifyctx) (EVP_PKEY_CTX *ctx,
 const unsigned char *sig,
 int siglen,
 EVP_MD_CTX *mctx));
 void EVP_PKEY_meth_get_encrypt(const EVP_PKEY_METHOD *pmeth,
 int (**pencrypt_init) (EVP_PKEY_CTX *ctx),
 int (**pencryptfn) (EVP_PKEY_CTX *ctx,
 unsigned char *out,
 size_t *outlen,
 const unsigned char *in,
 size_t inlen));
 void EVP_PKEY_meth_get_decrypt(const EVP_PKEY_METHOD *pmeth,
 int (**pdecrypt_init) (EVP_PKEY_CTX *ctx),
 int (**pdecrypt) (EVP_PKEY_CTX *ctx,
 unsigned char *out,
 size_t *outlen,
 const unsigned char *in,
 size_t inlen));
 void EVP_PKEY_meth_get_derive(const EVP_PKEY_METHOD *pmeth,
 int (**pderive_init) (EVP_PKEY_CTX *ctx),
 int (**pderive) (EVP_PKEY_CTX *ctx,
 unsigned char *key,
 size_t *keylen));
 void EVP_PKEY_meth_get_ctrl(const EVP_PKEY_METHOD *pmeth,
 int (**pctrl) (EVP_PKEY_CTX *ctx, int type, int p1,
 void *p2),
 int (**pctrl_str) (EVP_PKEY_CTX *ctx,
 const char *type,
 const char *value));
 void EVP_PKEY_meth_get_digestsign(EVP_PKEY_METHOD *pmeth,
 int (**digestsign) (EVP_MD_CTX *ctx,
 unsigned char *sig,
 size_t *siglen,
 const unsigned char *tbs,
 size_t tbslen));
 void EVP_PKEY_meth_get_digestverify(EVP_PKEY_METHOD *pmeth,
 int (**digestverify) (EVP_MD_CTX *ctx,
 const unsigned char *sig,
 size_t siglen,
 const unsigned char *tbs,
 size_t tbslen));
 void EVP_PKEY_meth_get_check(const EVP_PKEY_METHOD *pmeth,
 int (**pcheck) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_get_public_check(const EVP_PKEY_METHOD *pmeth,
 int (**pcheck) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_get_param_check(const EVP_PKEY_METHOD *pmeth,
 int (**pcheck) (EVP_PKEY *pkey));
 void EVP_PKEY_meth_get_digest_custom(EVP_PKEY_METHOD *pmeth,
 int (**pdigest_custom) (EVP_PKEY_CTX *ctx,
 EVP_MD_CTX *mctx));</code></pre>

<h1 id="DESCRIPTION">DESCRIPTION</h1>

EVP_PKEY_METHOD is a structure which holds a set of methods for a specific public key cryptographic algorithm. Those methods are usually used to perform different jobs, such as generating a key, signing or verifying, encrypting or decrypting, etc.

There are two places where the EVP_PKEY_METHOD objects are stored: one is a built-in static array representing the standard methods for different algorithms, and the other one is a stack of user-defined application-specific methods, which can be manipulated by using <a href="../man3/EVP_PKEY_meth_add0.html">EVP_PKEY_meth_add0(3)</a>.

The EVP_PKEY_METHOD objects are usually referenced by EVP_PKEY_CTX objects.

<h2 id="Methods">Methods</h2>

The methods are the underlying implementations of a particular public key algorithm present by the EVP_PKEY_CTX object.

<pre><code> int (*init) (EVP_PKEY_CTX *ctx);
 int (*copy) (EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src);
 void (*cleanup) (EVP_PKEY_CTX *ctx);</code></pre>

The init() method is called to initialize algorithm-specific data when a new EVP_PKEY_CTX is created. As opposed to init(), the cleanup() method is called when an EVP_PKEY_CTX is freed. The copy() method is called when an EVP_PKEY_CTX is being duplicated. Refer to <a href="../man3/EVP_PKEY_CTX_new.html">EVP_PKEY_CTX_new(3)</a>, <a href="../man3/EVP_PKEY_CTX_new_id.html">EVP_PKEY_CTX_new_id(3)</a>, <a href="../man3/EVP_PKEY_CTX_free.html">EVP_PKEY_CTX_free(3)</a> and <a href="../man3/EVP_PKEY_CTX_dup.html">EVP_PKEY_CTX_dup(3)</a>.

<pre><code> int (*paramgen_init) (EVP_PKEY_CTX *ctx);
 int (*paramgen) (EVP_PKEY_CTX *ctx, EVP_PKEY *pkey);</code></pre>

The paramgen_init() and paramgen() methods deal with key parameter generation. They are called by <a href="../man3/EVP_PKEY_paramgen_init.html">EVP_PKEY_paramgen_init(3)</a> and <a href="../man3/EVP_PKEY_paramgen.html">EVP_PKEY_paramgen(3)</a> to handle the parameter generation process.

<pre><code> int (*keygen_init) (EVP_PKEY_CTX *ctx);
 int (*keygen) (EVP_PKEY_CTX *ctx, EVP_PKEY *pkey);</code></pre>

The keygen_init() and keygen() methods are used to generate the actual key for the specified algorithm. They are called by <a href="../man3/EVP_PKEY_keygen_init.html">EVP_PKEY_keygen_init(3)</a> and <a href="../man3/EVP_PKEY_keygen.html">EVP_PKEY_keygen(3)</a>.

<pre><code> int (*sign_init) (EVP_PKEY_CTX *ctx);
 int (*sign) (EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
 const unsigned char *tbs, size_t tbslen);</code></pre>

The sign_init() and sign() methods are used to generate the signature of a piece of data using a private key. They are called by <a href="../man3/EVP_PKEY_sign_init.html">EVP_PKEY_sign_init(3)</a> and <a href="../man3/EVP_PKEY_sign.html">EVP_PKEY_sign(3)</a>.

<pre><code> int (*verify_init) (EVP_PKEY_CTX *ctx);
 int (*verify) (EVP_PKEY_CTX *ctx,
 const unsigned char *sig, size_t siglen,
 const unsigned char *tbs, size_t tbslen);</code></pre>

The verify_init() and verify() methods are used to verify whether a signature is valid. They are called by <a href="../man3/EVP_PKEY_verify_init.html">EVP_PKEY_verify_init(3)</a> and <a href="../man3/EVP_PKEY_verify.html">EVP_PKEY_verify(3)</a>.

<pre><code> int (*verify_recover_init) (EVP_PKEY_CTX *ctx);
 int (*verify_recover) (EVP_PKEY_CTX *ctx,
 unsigned char *rout, size_t *routlen,
 const unsigned char *sig, size_t siglen);</code></pre>

The verify_recover_init() and verify_recover() methods are used to verify a signature and then recover the digest from the signature (for instance, a signature that was generated by RSA signing algorithm). They are called by <a href="../man3/EVP_PKEY_verify_recover_init.html">EVP_PKEY_verify_recover_init(3)</a> and <a href="../man3/EVP_PKEY_verify_recover.html">EVP_PKEY_verify_recover(3)</a>.

<pre><code> int (*signctx_init) (EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx);
 int (*signctx) (EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
 EVP_MD_CTX *mctx);</code></pre>

The signctx_init() and signctx() methods are used to sign a digest present by a EVP_MD_CTX object. They are called by the EVP_DigestSign functions. See <a href="../man3/EVP_DigestSignInit.html">EVP_DigestSignInit(3)</a> for details.

<pre><code> int (*verifyctx_init) (EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx);
 int (*verifyctx) (EVP_PKEY_CTX *ctx, const unsigned char *sig, int siglen,
 EVP_MD_CTX *mctx);</code></pre>

The verifyctx_init() and verifyctx() methods are used to verify a signature against the data in a EVP_MD_CTX object. They are called by the various EVP_DigestVerify functions. See <a href="../man3/EVP_DigestVerifyInit.html">EVP_DigestVerifyInit(3)</a> for details.

<pre><code> int (*encrypt_init) (EVP_PKEY_CTX *ctx);
 int (*encrypt) (EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen,
 const unsigned char *in, size_t inlen);</code></pre>

The encrypt_init() and encrypt() methods are used to encrypt a piece of data. They are called by <a href="../man3/EVP_PKEY_encrypt_init.html">EVP_PKEY_encrypt_init(3)</a> and <a href="../man3/EVP_PKEY_encrypt.html">EVP_PKEY_encrypt(3)</a>.

<pre><code> int (*decrypt_init) (EVP_PKEY_CTX *ctx);
 int (*decrypt) (EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen,
 const unsigned char *in, size_t inlen);</code></pre>

The decrypt_init() and decrypt() methods are used to decrypt a piece of data. They are called by <a href="../man3/EVP_PKEY_decrypt_init.html">EVP_PKEY_decrypt_init(3)</a> and <a href="../man3/EVP_PKEY_decrypt.html">EVP_PKEY_decrypt(3)</a>.

<pre><code> int (*derive_init) (EVP_PKEY_CTX *ctx);
 int (*derive) (EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen);</code></pre>

The derive_init() and derive() methods are used to derive the shared secret from a public key algorithm (for instance, the DH algorithm). They are called by <a href="../man3/EVP_PKEY_derive_init.html">EVP_PKEY_derive_init(3)</a> and <a href="../man3/EVP_PKEY_derive.html">EVP_PKEY_derive(3)</a>.

<pre><code> int (*ctrl) (EVP_PKEY_CTX *ctx, int type, int p1, void *p2);
 int (*ctrl_str) (EVP_PKEY_CTX *ctx, const char *type, const char *value);</code></pre>

The ctrl() and ctrl_str() methods are used to adjust algorithm-specific settings. See <a href="../man3/EVP_PKEY_CTX_ctrl.html">EVP_PKEY_CTX_ctrl(3)</a> and related functions for details.

<pre><code> int (*digestsign) (EVP_MD_CTX *ctx, unsigned char *sig, size_t *siglen,
 const unsigned char *tbs, size_t tbslen);
 int (*digestverify) (EVP_MD_CTX *ctx, const unsigned char *sig,
 size_t siglen, const unsigned char *tbs,
 size_t tbslen);</code></pre>

The digestsign() and digestverify() methods are used to generate or verify a signature in a one-shot mode. They could be called by <a href="../man3/EVP_DigestSign.html">EVP_DigestSign(3)</a> and <a href="../man3/EVP_DigestVerify.html">EVP_DigestVerify(3)</a>.

<pre><code> int (*check) (EVP_PKEY *pkey);
 int (*public_check) (EVP_PKEY *pkey);
 int (*param_check) (EVP_PKEY *pkey);</code></pre>

The check(), public_check() and param_check() methods are used to validate a key-pair, the public component and parameters respectively for a given pkey. They could be called by <a href="../man3/EVP_PKEY_check.html">EVP_PKEY_check(3)</a>, <a href="../man3/EVP_PKEY_public_check.html">EVP_PKEY_public_check(3)</a> and <a href="../man3/EVP_PKEY_param_check.html">EVP_PKEY_param_check(3)</a> respectively.

<pre><code> int (*digest_custom) (EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx);</code></pre>

The digest_custom() method is used to generate customized digest content before the real message is passed to functions like <a href="../man3/EVP_DigestSignUpdate.html">EVP_DigestSignUpdate(3)</a> or <a href="../man3/EVP_DigestVerifyInit.html">EVP_DigestVerifyInit(3)</a>. This is usually required by some public key signature algorithms like SM2 which requires a hashed prefix to the message to be signed. The digest_custom() function will be called by <a href="../man3/EVP_DigestSignInit.html">EVP_DigestSignInit(3)</a> and <a href="../man3/EVP_DigestVerifyInit.html">EVP_DigestVerifyInit(3)</a>.

<h2 id="Functions">Functions</h2>

EVP_PKEY_meth_new() creates and returns a new EVP_PKEY_METHOD object, and associates the given id and flags. The following flags are supported:

<pre><code> EVP_PKEY_FLAG_AUTOARGLEN
 EVP_PKEY_FLAG_SIGCTX_CUSTOM</code></pre>

If an EVP_PKEY_METHOD is set with the EVP_PKEY_FLAG_AUTOARGLEN flag, the maximum size of the output buffer will be automatically calculated or checked in corresponding EVP methods by the EVP framework. Thus the implementations of these methods don&#39;t need to care about handling the case of returning output buffer size by themselves. For details on the output buffer size, refer to <a href="../man3/EVP_PKEY_sign.html">EVP_PKEY_sign(3)</a>.

The EVP_PKEY_FLAG_SIGCTX_CUSTOM is used to indicate the signctx() method of an EVP_PKEY_METHOD is always called by the EVP framework while doing a digest signing operation by calling <a href="../man3/EVP_DigestSignFinal.html">EVP_DigestSignFinal(3)</a>.

EVP_PKEY_meth_free() frees an existing EVP_PKEY_METHOD pointed by pmeth.

EVP_PKEY_meth_copy() copies an EVP_PKEY_METHOD object from src to dst.

EVP_PKEY_meth_find() finds an EVP_PKEY_METHOD object with the id. This function first searches through the user-defined method objects and then the built-in objects.

EVP_PKEY_meth_add0() adds pmeth to the user defined stack of methods.

EVP_PKEY_meth_remove() removes an EVP_PKEY_METHOD object added by EVP_PKEY_meth_add0().

The EVP_PKEY_meth_set functions set the corresponding fields of EVP_PKEY_METHOD structure with the arguments passed.

The EVP_PKEY_meth_get functions get the corresponding fields of EVP_PKEY_METHOD structure to the arguments provided.

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

EVP_PKEY_meth_new() returns a pointer to a new EVP_PKEY_METHOD object or returns NULL on error.

EVP_PKEY_meth_free() and EVP_PKEY_meth_copy() do not return values.

EVP_PKEY_meth_find() returns a pointer to the found EVP_PKEY_METHOD object or returns NULL if not found.

EVP_PKEY_meth_add0() returns 1 if method is added successfully or 0 if an error occurred.

EVP_PKEY_meth_remove() returns 1 if method is removed successfully or 0 if an error occurred.

All EVP_PKEY_meth_set and EVP_PKEY_meth_get functions have no return values. For the &#39;get&#39; functions, function pointers are returned by arguments.

<h1 id="COPYRIGHT">COPYRIGHT</h1>

Licensed under the OpenSSL license (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>.

</body>

</html>