237 lines
11 KiB
HTML
Executable File
237 lines
11 KiB
HTML
Executable File
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<title>ECDSA_SIG_new</title>
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<meta http-equiv="content-type" content="text/html; charset=utf-8" />
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<link rev="made" href="mailto:root@localhost" />
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</head>
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<body style="background-color: white">
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<!-- INDEX BEGIN -->
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<div name="index">
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<p><a name="__index__"></a></p>
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<ul>
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<li><a href="#name">NAME</a></li>
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<li><a href="#synopsis">SYNOPSIS</a></li>
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<li><a href="#description">DESCRIPTION</a></li>
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<li><a href="#return_values">RETURN VALUES</a></li>
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<li><a href="#examples">EXAMPLES</a></li>
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<li><a href="#conforming_to">CONFORMING TO</a></li>
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<li><a href="#see_also">SEE ALSO</a></li>
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<li><a href="#history">HISTORY</a></li>
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<li><a href="#copyright">COPYRIGHT</a></li>
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</ul>
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<hr name="index" />
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</div>
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<!-- INDEX END -->
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<p>
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</p>
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<hr />
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<h1><a name="name">NAME</a></h1>
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<p>ECDSA_SIG_get0, ECDSA_SIG_get0_r, ECDSA_SIG_get0_s, ECDSA_SIG_set0,
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ECDSA_SIG_new, ECDSA_SIG_free, ECDSA_size, ECDSA_sign, ECDSA_do_sign,
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ECDSA_verify, ECDSA_do_verify, ECDSA_sign_setup, ECDSA_sign_ex,
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ECDSA_do_sign_ex - low level elliptic curve digital signature algorithm (ECDSA)
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functions</p>
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<p>
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</p>
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<hr />
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<h1><a name="synopsis">SYNOPSIS</a></h1>
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<pre>
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#include <openssl/ecdsa.h></pre>
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<pre>
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ECDSA_SIG *ECDSA_SIG_new(void);
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void ECDSA_SIG_free(ECDSA_SIG *sig);
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void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps);
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const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig);
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const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig);
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int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s);</pre>
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<p>Deprecated since OpenSSL 3.0, can be hidden entirely by defining
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<strong>OPENSSL_API_COMPAT</strong> with a suitable version value, see
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<em>openssl_user_macros(7)</em>:</p>
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<pre>
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int ECDSA_size(const EC_KEY *eckey);</pre>
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<pre>
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int ECDSA_sign(int type, const unsigned char *dgst, int dgstlen,
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unsigned char *sig, unsigned int *siglen, EC_KEY *eckey);
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ECDSA_SIG *ECDSA_do_sign(const unsigned char *dgst, int dgst_len,
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EC_KEY *eckey);</pre>
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<pre>
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int ECDSA_verify(int type, const unsigned char *dgst, int dgstlen,
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const unsigned char *sig, int siglen, EC_KEY *eckey);
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int ECDSA_do_verify(const unsigned char *dgst, int dgst_len,
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const ECDSA_SIG *sig, EC_KEY* eckey);</pre>
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<pre>
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ECDSA_SIG *ECDSA_do_sign_ex(const unsigned char *dgst, int dgstlen,
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const BIGNUM *kinv, const BIGNUM *rp,
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EC_KEY *eckey);
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int ECDSA_sign_setup(EC_KEY *eckey, BN_CTX *ctx, BIGNUM **kinv, BIGNUM **rp);
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int ECDSA_sign_ex(int type, const unsigned char *dgst, int dgstlen,
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unsigned char *sig, unsigned int *siglen,
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const BIGNUM *kinv, const BIGNUM *rp, EC_KEY *eckey);</pre>
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<p>
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</p>
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<hr />
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<h1><a name="description">DESCRIPTION</a></h1>
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<p><strong>ECDSA_SIG</strong> is an opaque structure consisting of two BIGNUMs for the
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<strong>r</strong> and <strong>s</strong> value of an ECDSA signature (see X9.62 or FIPS 186-2).</p>
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<p><code>ECDSA_SIG_new()</code> allocates an empty <strong>ECDSA_SIG</strong> structure. Note: before
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OpenSSL 1.1.0 the: the <strong>r</strong> and <strong>s</strong> components were initialised.</p>
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<p><code>ECDSA_SIG_free()</code> frees the <strong>ECDSA_SIG</strong> structure <strong>sig</strong>.</p>
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<p>ECDSA_SIG_get0() returns internal pointers the <strong>r</strong> and <strong>s</strong> values contained
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in <strong>sig</strong> and stores them in <strong>*pr</strong> and <strong>*ps</strong>, respectively.
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The pointer <strong>pr</strong> or <strong>ps</strong> can be NULL, in which case the corresponding value
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is not returned.</p>
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<p>The values <strong>r</strong>, <strong>s</strong> can also be retrieved separately by the corresponding
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function ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s(), respectively.</p>
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<p>The <strong>r</strong> and <strong>s</strong> values can be set by calling ECDSA_SIG_set0() and passing the
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new values for <strong>r</strong> and <strong>s</strong> as parameters to the function. Calling this
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function transfers the memory management of the values to the ECDSA_SIG object,
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and therefore the values that have been passed in should not be freed directly
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after this function has been called.</p>
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<p>See <em>i2d_ECDSA_SIG(3)</em> and <em>d2i_ECDSA_SIG(3)</em> for information about encoding
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and decoding ECDSA signatures to/from DER.</p>
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<p>All of the functions described below are deprecated. Applications should
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use the higher level <strong>EVP</strong> interface such as <em>EVP_DigestSignInit(3)</em>
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or <em>EVP_DigestVerifyInit(3)</em> instead.</p>
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<p><code>ECDSA_size()</code> returns the maximum length of a DER encoded ECDSA signature
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created with the private EC key <strong>eckey</strong>. To obtain the actual signature
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size use <em>EVP_PKEY_sign(3)</em> with a NULL <strong>sig</strong> parameter.</p>
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<p><code>ECDSA_sign()</code> computes a digital signature of the <strong>dgstlen</strong> bytes hash value
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<strong>dgst</strong> using the private EC key <strong>eckey</strong>. The DER encoded signatures is
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stored in <strong>sig</strong> and its length is returned in <strong>sig_len</strong>. Note: <strong>sig</strong> must
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point to ECDSA_size(eckey) bytes of memory. The parameter <strong>type</strong> is currently
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ignored. <code>ECDSA_sign()</code> is wrapper function for <code>ECDSA_sign_ex()</code> with <strong>kinv</strong>
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and <strong>rp</strong> set to NULL.</p>
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<p><code>ECDSA_do_sign()</code> is similar to <code>ECDSA_sign()</code> except the signature is returned
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as a newly allocated <strong>ECDSA_SIG</strong> structure (or NULL on error). <code>ECDSA_do_sign()</code>
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is a wrapper function for <code>ECDSA_do_sign_ex()</code> with <strong>kinv</strong> and <strong>rp</strong> set to
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NULL.</p>
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<p><code>ECDSA_verify()</code> verifies that the signature in <strong>sig</strong> of size <strong>siglen</strong> is a
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valid ECDSA signature of the hash value <strong>dgst</strong> of size <strong>dgstlen</strong> using the
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public key <strong>eckey</strong>. The parameter <strong>type</strong> is ignored.</p>
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<p><code>ECDSA_do_verify()</code> is similar to <code>ECDSA_verify()</code> except the signature is
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presented in the form of a pointer to an <strong>ECDSA_SIG</strong> structure.</p>
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<p>The remaining functions utilise the internal <strong>kinv</strong> and <strong>r</strong> values used
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during signature computation. Most applications will never need to call these
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and some external ECDSA ENGINE implementations may not support them at all if
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either <strong>kinv</strong> or <strong>r</strong> is not <strong>NULL</strong>.</p>
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<p><code>ECDSA_sign_setup()</code> may be used to precompute parts of the signing operation.
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<strong>eckey</strong> is the private EC key and <strong>ctx</strong> is a pointer to <strong>BN_CTX</strong> structure
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(or NULL). The precomputed values or returned in <strong>kinv</strong> and <strong>rp</strong> and can be
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used in a later call to <code>ECDSA_sign_ex()</code> or <code>ECDSA_do_sign_ex()</code>.</p>
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<p><code>ECDSA_sign_ex()</code> computes a digital signature of the <strong>dgstlen</strong> bytes hash value
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<strong>dgst</strong> using the private EC key <strong>eckey</strong> and the optional pre-computed values
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<strong>kinv</strong> and <strong>rp</strong>. The DER encoded signature is stored in <strong>sig</strong> and its
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length is returned in <strong>sig_len</strong>. Note: <strong>sig</strong> must point to ECDSA_size(eckey)
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bytes of memory. The parameter <strong>type</strong> is ignored.</p>
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<p><code>ECDSA_do_sign_ex()</code> is similar to <code>ECDSA_sign_ex()</code> except the signature is
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returned as a newly allocated <strong>ECDSA_SIG</strong> structure (or NULL on error).</p>
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<p>
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</p>
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<hr />
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<h1><a name="return_values">RETURN VALUES</a></h1>
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<p><code>ECDSA_SIG_new()</code> returns NULL if the allocation fails.</p>
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<p>ECDSA_SIG_set0() returns 1 on success or 0 on failure.</p>
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<p>ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s() return the corresponding value,
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or NULL if it is unset.</p>
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<p><code>ECDSA_size()</code> returns the maximum length signature or 0 on error.</p>
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<p><code>ECDSA_sign()</code>, <code>ECDSA_sign_ex()</code> and <code>ECDSA_sign_setup()</code> return 1 if successful
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or 0 on error.</p>
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<p><code>ECDSA_do_sign()</code> and <code>ECDSA_do_sign_ex()</code> return a pointer to an allocated
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<strong>ECDSA_SIG</strong> structure or NULL on error.</p>
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<p><code>ECDSA_verify()</code> and <code>ECDSA_do_verify()</code> return 1 for a valid
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signature, 0 for an invalid signature and -1 on error.
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The error codes can be obtained by <em>ERR_get_error(3)</em>.</p>
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<p>
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</p>
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<hr />
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<h1><a name="examples">EXAMPLES</a></h1>
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<p>Creating an ECDSA signature of a given SHA-256 hash value using the
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named curve prime256v1 (aka P-256).</p>
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<p>First step: create an EC_KEY object (note: this part is <strong>not</strong> ECDSA
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specific)</p>
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<pre>
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int ret;
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ECDSA_SIG *sig;
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EC_KEY *eckey;</pre>
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<pre>
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eckey = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
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if (eckey == NULL)
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/* error */
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if (EC_KEY_generate_key(eckey) == 0)
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/* error */</pre>
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<p>Second step: compute the ECDSA signature of a SHA-256 hash value
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using ECDSA_do_sign():</p>
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<pre>
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sig = ECDSA_do_sign(digest, 32, eckey);
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if (sig == NULL)
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/* error */</pre>
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<p>or using ECDSA_sign():</p>
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<pre>
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unsigned char *buffer, *pp;
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int buf_len;</pre>
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<pre>
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buf_len = ECDSA_size(eckey);
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buffer = OPENSSL_malloc(buf_len);
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pp = buffer;
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if (ECDSA_sign(0, dgst, dgstlen, pp, &buf_len, eckey) == 0)
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/* error */</pre>
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<p>Third step: verify the created ECDSA signature using ECDSA_do_verify():</p>
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<pre>
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ret = ECDSA_do_verify(digest, 32, sig, eckey);</pre>
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<p>or using ECDSA_verify():</p>
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<pre>
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ret = ECDSA_verify(0, digest, 32, buffer, buf_len, eckey);</pre>
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<p>and finally evaluate the return value:</p>
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<pre>
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if (ret == 1)
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/* signature ok */
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else if (ret == 0)
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/* incorrect signature */
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else
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/* error */</pre>
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<p>
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</p>
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<hr />
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<h1><a name="conforming_to">CONFORMING TO</a></h1>
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<p>ANSI X9.62, US Federal Information Processing Standard FIPS 186-2
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(Digital Signature Standard, DSS)</p>
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<p>
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</p>
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<hr />
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<h1><a name="see_also">SEE ALSO</a></h1>
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<p><em>EC_KEY_new(3)</em>,
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<em>EVP_DigestSignInit(3)</em>,
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<em>EVP_DigestVerifyInit(3)</em>,
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<em>EVP_PKEY_sign(3)</em>
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<em>i2d_ECDSA_SIG(3)</em>,
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<em>d2i_ECDSA_SIG(3)</em></p>
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<p>
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</p>
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<hr />
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<h1><a name="history">HISTORY</a></h1>
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<p>The <code>ECDSA_size()</code>, <code>ECDSA_sign()</code>, <code>ECDSA_do_sign()</code>, <code>ECDSA_verify()</code>,
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<code>ECDSA_do_verify()</code>, <code>ECDSA_sign_setup()</code>, <code>ECDSA_sign_ex()</code> and <code>ECDSA_do_sign_ex()</code>
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functions were deprecated in OpenSSL 3.0.</p>
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<p>
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</p>
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<hr />
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<h1><a name="copyright">COPYRIGHT</a></h1>
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<p>Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.</p>
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<p>Licensed under the Apache License 2.0 (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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<a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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</body>
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</html>
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