=head1 NAME
-ECDSA_SIG_get0, ECDSA_SIG_set0,
-ECDSA_SIG_new, ECDSA_SIG_free, i2d_ECDSA_SIG, d2i_ECDSA_SIG, 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
+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
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 i2d_ECDSA_SIG(const ECDSA_SIG *sig, unsigned char **pp);
- ECDSA_SIG *d2i_ECDSA_SIG(ECDSA_SIG **sig, const unsigned char **pp, long len);
int ECDSA_size(const EC_KEY *eckey);
int ECDSA_sign(int type, const unsigned char *dgst, int dgstlen,
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>.
+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
and therefore the values that have been passed in should not be freed directly
after this function has been called.
-i2d_ECDSA_SIG() creates the DER encoding of the ECDSA signature B<sig> and
-writes the encoded signature to B<*pp> (note: if B<pp> is NULL i2d_ECDSA_SIG()
-returns the expected length in bytes of the DER encoded signature).
-i2d_ECDSA_SIG() returns the length of the DER encoded signature (or 0 on
-error).
-
-d2i_ECDSA_SIG() decodes a DER encoded ECDSA signature and returns the decoded
-signature in a newly allocated B<ECDSA_SIG> structure. B<*sig> points to the
-buffer containing the DER encoded signature of size B<len>.
+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>.
=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
First step: create an EC_KEY object (note: this part is B<not> ECDSA
specific)
- int ret;
+ int ret;
ECDSA_SIG *sig;
- EC_KEY *eckey;
+ 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 */
- }
+ 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 */
- }
+ if (sig == NULL)
+ /* error */
or using ECDSA_sign():
unsigned char *buffer, *pp;
- int buf_len;
+ int buf_len;
+
buf_len = ECDSA_size(eckey);
- buffer = OPENSSL_malloc(buf_len);
+ buffer = OPENSSL_malloc(buf_len);
pp = buffer;
- if (ECDSA_sign(0, dgst, dgstlen, pp, &buf_len, eckey) == 0) {
- /* error */
- }
+ if (ECDSA_sign(0, dgst, dgstlen, pp, &buf_len, eckey) == 0)
+ /* error */
Third step: verify the created ECDSA signature using ECDSA_do_verify():
and finally evaluate the return value:
- if (ret == 1) {
- /* signature ok */
- } else if (ret == 0) {
- /* incorrect signature */
- } else {
- /* error */
- }
+ if (ret == 1)
+ /* signature ok */
+ else if (ret == 0)
+ /* incorrect signature */
+ else
+ /* error */
=head1 CONFORMING TO
=head1 SEE ALSO
-L<DSA_new(3)>,
+L<EC_KEY_new(3)>,
L<EVP_DigestSignInit(3)>,
-L<EVP_DigestVerifyInit(3)>
+L<EVP_DigestVerifyInit(3)>,
+L<i2d_ECDSA_SIG(3)>,
+L<d2i_ECDSA_SIG(3)>
=head1 COPYRIGHT
-Copyright 2004-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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>.
projects / openssl.git / blobdiff