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Title "ECDSA_SIG_NEW 3ossl"
ECDSA_SIG_NEW 3ossl "2023-09-19" "3.0.11" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
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"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"
Header "SYNOPSIS" .Vb 1 #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); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \fB\s-1ECDSA_SIG\s0 is an opaque structure consisting of two BIGNUMs for the \fIr and s value of an Elliptic Curve Digital Signature Algorithm (\s-1ECDSA\s0) signature (see \s-1FIPS186-4\s0 or X9.62). The \s-1ECDSA_SIG\s0 object was mainly used by the deprecated low level functions described in \fBECDSA_sign\|(3), it is still required in order to be able to set or get the values of \fIr and s into or from a signature. This is mainly used for testing purposes as shown in the \*(L"\s-1EXAMPLES\*(R"\s0.

\fBECDSA_SIG_new() allocates an empty \s-1ECDSA_SIG\s0 structure. Note: before OpenSSL 1.1.0, the r and s components were initialised.

\fBECDSA_SIG_free() frees the \s-1ECDSA_SIG\s0 structure sig.

\fBECDSA_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 \s-1NULL,\s0 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 \fBECDSA_SIG_set0(). Calling this function transfers the memory management of the values to the \s-1ECDSA_SIG\s0 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 \s-1ECDSA\s0 signatures to/from \s-1DER.\s0

"RETURN VALUES"
Header "RETURN VALUES" \fBECDSA_SIG_new() returns \s-1NULL\s0 if the allocation fails.

\fBECDSA_SIG_set0() returns 1 on success or 0 on failure.

\fBECDSA_SIG_get0_r() and ECDSA_SIG_get0_s() return the corresponding value, or \s-1NULL\s0 if it is unset.

"EXAMPLES"
Header "EXAMPLES" Extract signature r and s values from a \s-1ECDSA\s0 signature of size signaturelen:

.Vb 2 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); .Ve

Convert r and s byte arrays into an \s-1ECDSA_SIG\s0 signature of size signaturelen:

.Vb 4 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); .Ve

"CONFORMING TO"
Header "CONFORMING TO" \s-1ANSI X9.62, US\s0 Federal Information Processing Standard \s-1FIPS186-4\s0 (Digital Signature Standard, \s-1DSS\s0)
"SEE ALSO"
Header "SEE ALSO" \fBEC_KEY_new\|(3), \fBEVP_DigestSignInit\|(3), \fBEVP_DigestVerifyInit\|(3), \fBEVP_PKEY_sign\|(3) \fBi2d_ECDSA_SIG\|(3), \fBd2i_ECDSA_SIG\|(3), \fBECDSA_sign\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2004-2022 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.