mirror of
https://github.com/openssl/openssl.git
synced 2024-12-03 05:41:46 +08:00
bbda79976b
They incorrectly said that i2d_ECDSA_SIG returns 0 on error. In fact it returns a negative value on error. We fix this by moving the i2d_ECDSA_SIG/d2i_ECDSA_SIG docs onto the same page as all the other d2i/i2d docs. Fixes #9517 Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com> (Merged from https://github.com/openssl/openssl/pull/9533)
210 lines
7.5 KiB
Plaintext
210 lines
7.5 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
ECDSA_SIG_get0, ECDSA_SIG_get0_r, ECDSA_SIG_get0_s, ECDSA_SIG_set0,
|
|
ECDSA_SIG_new, ECDSA_SIG_free, ECDSA_size, ECDSA_sign, ECDSA_do_sign,
|
|
ECDSA_verify, ECDSA_do_verify, ECDSA_sign_setup, ECDSA_sign_ex,
|
|
ECDSA_do_sign_ex - low level elliptic curve digital signature algorithm (ECDSA)
|
|
functions
|
|
|
|
=head1 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);
|
|
int ECDSA_size(const EC_KEY *eckey);
|
|
|
|
int ECDSA_sign(int type, const unsigned char *dgst, int dgstlen,
|
|
unsigned char *sig, unsigned int *siglen, EC_KEY *eckey);
|
|
ECDSA_SIG *ECDSA_do_sign(const unsigned char *dgst, int dgst_len,
|
|
EC_KEY *eckey);
|
|
|
|
int ECDSA_verify(int type, const unsigned char *dgst, int dgstlen,
|
|
const unsigned char *sig, int siglen, EC_KEY *eckey);
|
|
int ECDSA_do_verify(const unsigned char *dgst, int dgst_len,
|
|
const ECDSA_SIG *sig, EC_KEY* eckey);
|
|
|
|
ECDSA_SIG *ECDSA_do_sign_ex(const unsigned char *dgst, int dgstlen,
|
|
const BIGNUM *kinv, const BIGNUM *rp,
|
|
EC_KEY *eckey);
|
|
int ECDSA_sign_setup(EC_KEY *eckey, BN_CTX *ctx, BIGNUM **kinv, BIGNUM **rp);
|
|
int ECDSA_sign_ex(int type, const unsigned char *dgst, int dgstlen,
|
|
unsigned char *sig, unsigned int *siglen,
|
|
const BIGNUM *kinv, const BIGNUM *rp, EC_KEY *eckey);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
Note: these functions provide a low level interface to ECDSA. Most
|
|
applications should use the higher level B<EVP> interface such as
|
|
L<EVP_DigestSignInit(3)> or L<EVP_DigestVerifyInit(3)> instead.
|
|
|
|
B<ECDSA_SIG> is an opaque structure consisting of two BIGNUMs for the
|
|
B<r> and B<s> value of an ECDSA signature (see X9.62 or FIPS 186-2).
|
|
|
|
ECDSA_SIG_new() allocates an empty B<ECDSA_SIG> structure. Note: before
|
|
OpenSSL 1.1.0 the: the B<r> and B<s> components were initialised.
|
|
|
|
ECDSA_SIG_free() frees the B<ECDSA_SIG> structure B<sig>.
|
|
|
|
ECDSA_SIG_get0() returns internal pointers the B<r> and B<s> values contained
|
|
in B<sig> and stores them in B<*pr> and B<*ps>, respectively.
|
|
The pointer B<pr> or B<ps> can be NULL, in which case the corresponding value
|
|
is not returned.
|
|
|
|
The values B<r>, B<s> can also be retrieved separately by the corresponding
|
|
function ECDSA_SIG_get0_r() and ECDSA_SIG_get0_s(), respectively.
|
|
|
|
The B<r> and B<s> values can be set by calling ECDSA_SIG_set0() and passing the
|
|
new values for B<r> and B<s> as parameters to the function. 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 directly
|
|
after this function has been called.
|
|
|
|
See L<i2d_ECDSA_SIG(3)> and L<d2i_ECDSA_SIG(3)> for information about encoding
|
|
and decoding ECDSA signatures to/from DER.
|
|
|
|
ECDSA_size() returns the maximum length of a DER encoded ECDSA signature
|
|
created with the private EC key B<eckey>.
|
|
|
|
ECDSA_sign() computes a digital signature of the B<dgstlen> bytes hash value
|
|
B<dgst> using the private EC key B<eckey>. The DER encoded signatures is
|
|
stored in B<sig> and its length is returned in B<sig_len>. Note: B<sig> must
|
|
point to ECDSA_size(eckey) bytes of memory. The parameter B<type> is currently
|
|
ignored. ECDSA_sign() is wrapper function for ECDSA_sign_ex() with B<kinv>
|
|
and B<rp> set to NULL.
|
|
|
|
ECDSA_do_sign() is similar to ECDSA_sign() except the signature is returned
|
|
as a newly allocated B<ECDSA_SIG> structure (or NULL on error). ECDSA_do_sign()
|
|
is a wrapper function for ECDSA_do_sign_ex() with B<kinv> and B<rp> set to
|
|
NULL.
|
|
|
|
ECDSA_verify() verifies that the signature in B<sig> of size B<siglen> is a
|
|
valid ECDSA signature of the hash value B<dgst> of size B<dgstlen> using the
|
|
public key B<eckey>. The parameter B<type> is ignored.
|
|
|
|
ECDSA_do_verify() is similar to ECDSA_verify() except the signature is
|
|
presented in the form of a pointer to an B<ECDSA_SIG> structure.
|
|
|
|
The remaining functions utilise the internal B<kinv> and B<r> values used
|
|
during signature computation. Most applications will never need to call these
|
|
and some external ECDSA ENGINE implementations may not support them at all if
|
|
either B<kinv> or B<r> is not B<NULL>.
|
|
|
|
ECDSA_sign_setup() may be used to precompute parts of the signing operation.
|
|
B<eckey> is the private EC key and B<ctx> is a pointer to B<BN_CTX> structure
|
|
(or NULL). The precomputed values or returned in B<kinv> and B<rp> and can be
|
|
used in a later call to ECDSA_sign_ex() or ECDSA_do_sign_ex().
|
|
|
|
ECDSA_sign_ex() computes a digital signature of the B<dgstlen> bytes hash value
|
|
B<dgst> using the private EC key B<eckey> and the optional pre-computed values
|
|
B<kinv> and B<rp>. The DER encoded signature is stored in B<sig> and its
|
|
length is returned in B<sig_len>. Note: B<sig> must point to ECDSA_size(eckey)
|
|
bytes of memory. The parameter B<type> is ignored.
|
|
|
|
ECDSA_do_sign_ex() is similar to ECDSA_sign_ex() except the signature is
|
|
returned as a newly allocated B<ECDSA_SIG> structure (or NULL on error).
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
ECDSA_SIG_new() 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.
|
|
|
|
ECDSA_size() returns the maximum length signature or 0 on error.
|
|
|
|
ECDSA_sign(), ECDSA_sign_ex() and ECDSA_sign_setup() return 1 if successful
|
|
or 0 on error.
|
|
|
|
ECDSA_do_sign() and ECDSA_do_sign_ex() return a pointer to an allocated
|
|
B<ECDSA_SIG> structure or NULL on error.
|
|
|
|
ECDSA_verify() and ECDSA_do_verify() return 1 for a valid
|
|
signature, 0 for an invalid signature and -1 on error.
|
|
The error codes can be obtained by L<ERR_get_error(3)>.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
Creating an ECDSA signature of a given SHA-256 hash value using the
|
|
named curve prime256v1 (aka P-256).
|
|
|
|
First step: create an EC_KEY object (note: this part is B<not> ECDSA
|
|
specific)
|
|
|
|
int ret;
|
|
ECDSA_SIG *sig;
|
|
EC_KEY *eckey;
|
|
|
|
eckey = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
|
|
if (eckey == NULL)
|
|
/* error */
|
|
if (EC_KEY_generate_key(eckey) == 0)
|
|
/* error */
|
|
|
|
Second step: compute the ECDSA signature of a SHA-256 hash value
|
|
using ECDSA_do_sign():
|
|
|
|
sig = ECDSA_do_sign(digest, 32, eckey);
|
|
if (sig == NULL)
|
|
/* error */
|
|
|
|
or using ECDSA_sign():
|
|
|
|
unsigned char *buffer, *pp;
|
|
int buf_len;
|
|
|
|
buf_len = ECDSA_size(eckey);
|
|
buffer = OPENSSL_malloc(buf_len);
|
|
pp = buffer;
|
|
if (ECDSA_sign(0, dgst, dgstlen, pp, &buf_len, eckey) == 0)
|
|
/* error */
|
|
|
|
Third step: verify the created ECDSA signature using ECDSA_do_verify():
|
|
|
|
ret = ECDSA_do_verify(digest, 32, sig, eckey);
|
|
|
|
or using ECDSA_verify():
|
|
|
|
ret = ECDSA_verify(0, digest, 32, buffer, buf_len, eckey);
|
|
|
|
and finally evaluate the return value:
|
|
|
|
if (ret == 1)
|
|
/* signature ok */
|
|
else if (ret == 0)
|
|
/* incorrect signature */
|
|
else
|
|
/* error */
|
|
|
|
=head1 CONFORMING TO
|
|
|
|
ANSI X9.62, US Federal Information Processing Standard FIPS 186-2
|
|
(Digital Signature Standard, DSS)
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EC_KEY_new(3)>,
|
|
L<EVP_DigestSignInit(3)>,
|
|
L<EVP_DigestVerifyInit(3)>,
|
|
L<i2d_ECDSA_SIG(3)>,
|
|
L<d2i_ECDSA_SIG(3)>
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2004-2018 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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|