+++ /dev/null
-=pod
-
-=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
-
-=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);
- 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,
- 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>.
-
-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.
-
-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>.
-
-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 it's 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 signatures is stored in B<sig> and it's
-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_set0() returns 1 on success or 0 on failure.
-
-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<dsa(3)>,
-L<EVP_DigestSignInit(3)>,
-L<EVP_DigestVerifyInit(3)>
-
-=head1 COPYRIGHT
-
-Copyright 2004-2016 The OpenSSL Project Authors. All Rights Reserved.
-
-Licensed under the OpenSSL license (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
projects / openssl.git / blobdiff