ECDSA_SIG_NEW(3ossl) OpenSSL ECDSA_SIG_NEW(3ossl)
NAME
ECDSA_SIG_new, ECDSA_SIG_free, ECDSA_SIG_get0, ECDSA_SIG_get0_r,
ECDSA_SIG_get0_s, ECDSA_SIG_set0 - Functions for creating, destroying
and manipulating ECDSA_SIG objects
SYNOPSIS
#include <openssl/ecdsa.h>
ECDSA_SIG *ECDSA_SIG_new(void);
void ECDSA_SIG_free(ECDSA_SIG *sig);
void ECDSA_SIG_get0(const ECDSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps);
const BIGNUM *ECDSA_SIG_get0_r(const ECDSA_SIG *sig);
const BIGNUM *ECDSA_SIG_get0_s(const ECDSA_SIG *sig);
int ECDSA_SIG_set0(ECDSA_SIG *sig, BIGNUM *r, BIGNUM *s);
DESCRIPTION
ECDSA_SIG is an opaque structure consisting of two BIGNUMs for the r
and s value of an Elliptic Curve Digital Signature Algorithm (ECDSA)
signature (see FIPS186-4 or X9.62). The ECDSA_SIG object was mainly
used by the deprecated low level functions described in ECDSA_sign(3),
it is still required in order to be able to set or get the values of r
and s into or from a signature. This is mainly used for testing
purposes as shown in the "EXAMPLES".
ECDSA_SIG_new(3) allocates an empty ECDSA_SIG structure. Note: before
OpenSSL 1.1.0, the r and s components were initialised.
ECDSA_SIG_free() frees the ECDSA_SIG structure sig. If the argument is
NULL, nothing is done.
ECDSA_SIG_get0() returns internal pointers the r and s values contained
in sig and stores them in *pr and *ps, respectively. The pointer pr or
ps can be NULL, in which case the corresponding value is not returned.
The values r, s can also be retrieved separately by the corresponding
function ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s(), respectively.
Non-NULL r and s values can be set on the sig by calling
ECDSA_SIG_set0(). Calling this function transfers the memory management
of the values to the ECDSA_SIG object, and therefore the values that
have been passed in should not be freed by the caller.
See i2d_ECDSA_SIG(3) and d2i_ECDSA_SIG(3) for information about
encoding and decoding ECDSA signatures to/from DER.
RETURN VALUES
ECDSA_SIG_new(3) returns NULL if the allocation fails.
ECDSA_SIG_set0() returns 1 on success or 0 on failure.
ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s() return the corresponding
value, or NULL if it is unset.
EXAMPLES
Extract signature r and s values from a ECDSA signature of size
signaturelen:
ECDSA_SIG *obj;
const BIGNUM *r, *s;
/* Load a signature into the ECDSA_SIG object */
obj = d2i_ECDSA_SIG(NULL, &signature, signaturelen);
if (obj == NULL)
/* error */
r = ECDSA_SIG_get0_r(obj);
s = ECDSA_SIG_get0_s(obj);
if (r == NULL || s == NULL)
/* error */
/* Use BN_bn2binpad() here to convert to r and s into byte arrays */
/*
* Do not try to access I<r> or I<s> after calling ECDSA_SIG_free(),
* as they are both freed by this call.
*/
ECDSA_SIG_free(obj);
Convert r and s byte arrays into an ECDSA_SIG signature of size
signaturelen:
ECDSA_SIG *obj = NULL;
unsigned char *signature = NULL;
size_t signaturelen;
BIGNUM *rbn = NULL, *sbn = NULL;
obj = ECDSA_SIG_new();
if (obj == NULL)
/* error */
rbn = BN_bin2bn(r, rlen, NULL);
sbn = BN_bin2bn(s, slen, NULL);
if (rbn == NULL || sbn == NULL)
/* error */
if (!ECDSA_SIG_set0(obj, rbn, sbn))
/* error */
/* Set these to NULL since they are now owned by obj */
rbn = sbn = NULL;
signaturelen = i2d_ECDSA_SIG(obj, &signature);
if (signaturelen <= 0)
/* error */
/*
* This signature could now be passed to L<EVP_DigestVerify(3)>
* or L<EVP_DigestVerifyFinal(3)>
*/
BN_free(rbn);
BN_free(sbn);
OPENSSL_free(signature);
ECDSA_SIG_free(obj);
CONFORMING TO
ANSI X9.62, US Federal Information Processing Standard FIPS186-4
(Digital Signature Standard, DSS)
SEE ALSO
EC_KEY_new(3), EVP_DigestSignInit(3), EVP_DigestVerifyInit(3),
EVP_PKEY_sign(3) i2d_ECDSA_SIG(3), d2i_ECDSA_SIG(3), ECDSA_sign(3)
COPYRIGHT
Copyright 2004-2024 The OpenSSL Project Authors. All Rights Reserved.
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
<https://www.openssl.org/source/license.html>.
3.3.2 2024-09-04 ECDSA_SIG_NEW(3ossl)
openssl 3.3.2 - Generated Tue Sep 10 11:13:55 CDT 2024