Edit File: EVP_PKEY_sign_init.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_sign</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></li> <li><a href="#NOTES">NOTES</a></li> <li><a href="#RETURN-VALUES">RETURN VALUES</a></li> <li><a href="#EXAMPLES">EXAMPLES</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>EVP_PKEY_sign_init, EVP_PKEY_sign - sign using a public key algorithm</p> <h1 id="SYNOPSIS">SYNOPSIS</h1> <pre><code> #include <openssl/evp.h> int EVP_PKEY_sign_init(EVP_PKEY_CTX *ctx); int EVP_PKEY_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen, const unsigned char *tbs, size_t tbslen);</code></pre> <h1 id="DESCRIPTION">DESCRIPTION</h1> <p>The EVP_PKEY_sign_init() function initializes a public key algorithm context using key <b>pkey</b> for a signing operation.</p> <p>The EVP_PKEY_sign() function performs a public key signing operation using <b>ctx</b>. The data to be signed is specified using the <b>tbs</b> and <b>tbslen</b> parameters. If <b>sig</b> is <b>NULL</b> then the maximum size of the output buffer is written to the <b>siglen</b> parameter. If <b>sig</b> is not <b>NULL</b> then before the call the <b>siglen</b> parameter should contain the length of the <b>sig</b> buffer, if the call is successful the signature is written to <b>sig</b> and the amount of data written to <b>siglen</b>.</p> <h1 id="NOTES">NOTES</h1> <p>EVP_PKEY_sign() does not hash the data to be signed, and therefore is normally used to sign digests. For signing arbitrary messages, see the <a href="../man3/EVP_DigestSignInit.html">EVP_DigestSignInit(3)</a> and <a href="../man3/EVP_SignInit.html">EVP_SignInit(3)</a> signing interfaces instead.</p> <p>After the call to EVP_PKEY_sign_init() algorithm specific control operations can be performed to set any appropriate parameters for the operation (see <a href="../man3/EVP_PKEY_CTX_ctrl.html">EVP_PKEY_CTX_ctrl(3)</a>).</p> <p>The function EVP_PKEY_sign() can be called more than once on the same context if several operations are performed using the same parameters.</p> <h1 id="RETURN-VALUES">RETURN VALUES</h1> <p>EVP_PKEY_sign_init() and EVP_PKEY_sign() return 1 for success and 0 or a negative value for failure. In particular a return value of -2 indicates the operation is not supported by the public key algorithm.</p> <h1 id="EXAMPLES">EXAMPLES</h1> <p>Sign data using RSA with PKCS#1 padding and SHA256 digest:</p> <pre><code> #include <openssl/evp.h> #include <openssl/rsa.h> EVP_PKEY_CTX *ctx; /* md is a SHA-256 digest in this example. */ unsigned char *md, *sig; size_t mdlen = 32, siglen; EVP_PKEY *signing_key; /* * NB: assumes signing_key and md are set up before the next * step. signing_key must be an RSA private key and md must * point to the SHA-256 digest to be signed. */ ctx = EVP_PKEY_CTX_new(signing_key, NULL /* no engine */); if (!ctx) /* Error occurred */ if (EVP_PKEY_sign_init(ctx) <= 0) /* Error */ if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0) /* Error */ if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0) /* Error */ /* Determine buffer length */ if (EVP_PKEY_sign(ctx, NULL, &siglen, md, mdlen) <= 0) /* Error */ sig = OPENSSL_malloc(siglen); if (!sig) /* malloc failure */ if (EVP_PKEY_sign(ctx, sig, &siglen, md, mdlen) <= 0) /* Error */ /* Signature is siglen bytes written to buffer sig */</code></pre> <h1 id="SEE-ALSO">SEE ALSO</h1> <p><a href="../man3/EVP_PKEY_CTX_new.html">EVP_PKEY_CTX_new(3)</a>, <a href="../man3/EVP_PKEY_CTX_ctrl.html">EVP_PKEY_CTX_ctrl(3)</a>, <a href="../man3/EVP_PKEY_encrypt.html">EVP_PKEY_encrypt(3)</a>, <a href="../man3/EVP_PKEY_decrypt.html">EVP_PKEY_decrypt(3)</a>, <a href="../man3/EVP_PKEY_verify.html">EVP_PKEY_verify(3)</a>, <a href="../man3/EVP_PKEY_verify_recover.html">EVP_PKEY_verify_recover(3)</a>, <a href="../man3/EVP_PKEY_derive.html">EVP_PKEY_derive(3)</a></p> <h1 id="HISTORY">HISTORY</h1> <p>These functions were added in OpenSSL 1.0.0.</p> <h1 id="COPYRIGHT">COPYRIGHT</h1> <p>Copyright 2006-2019 The OpenSSL Project Authors. All Rights Reserved.</p> <p>Licensed under the OpenSSL license (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> </body> </html>