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Diffstat (limited to 'doc/crypto/DSA_sign.pod')
-rw-r--r-- | doc/crypto/DSA_sign.pod | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/doc/crypto/DSA_sign.pod b/doc/crypto/DSA_sign.pod new file mode 100644 index 0000000..97389e8 --- /dev/null +++ b/doc/crypto/DSA_sign.pod @@ -0,0 +1,66 @@ +=pod + +=head1 NAME + +DSA_sign, DSA_sign_setup, DSA_verify - DSA signatures + +=head1 SYNOPSIS + + #include <openssl/dsa.h> + + int DSA_sign(int type, const unsigned char *dgst, int len, + unsigned char *sigret, unsigned int *siglen, DSA *dsa); + + int DSA_sign_setup(DSA *dsa, BN_CTX *ctx, BIGNUM **kinvp, + BIGNUM **rp); + + int DSA_verify(int type, const unsigned char *dgst, int len, + unsigned char *sigbuf, int siglen, DSA *dsa); + +=head1 DESCRIPTION + +DSA_sign() computes a digital signature on the B<len> byte message +digest B<dgst> using the private key B<dsa> and places its ASN.1 DER +encoding at B<sigret>. The length of the signature is places in +*B<siglen>. B<sigret> must point to DSA_size(B<dsa>) bytes of memory. + +DSA_sign_setup() may be used to precompute part of the signing +operation in case signature generation is time-critical. It expects +B<dsa> to contain DSA parameters. It places the precomputed values +in newly allocated B<BIGNUM>s at *B<kinvp> and *B<rp>, after freeing +the old ones unless *B<kinvp> and *B<rp> are NULL. These values may +be passed to DSA_sign() in B<dsa-E<gt>kinv> and B<dsa-E<gt>r>. +B<ctx> is a pre-allocated B<BN_CTX> or NULL. + +DSA_verify() verifies that the signature B<sigbuf> of size B<siglen> +matches a given message digest B<dgst> of size B<len>. +B<dsa> is the signer's public key. + +The B<type> parameter is ignored. + +The PRNG must be seeded before DSA_sign() (or DSA_sign_setup()) +is called. + +=head1 RETURN VALUES + +DSA_sign() and DSA_sign_setup() return 1 on success, 0 on error. +DSA_verify() returns 1 for a valid signature, 0 for an incorrect +signature and -1 on error. The error codes can be obtained by +L<ERR_get_error(3)|ERR_get_error(3)>. + +=head1 CONFORMING TO + +US Federal Information Processing Standard FIPS 186 (Digital Signature +Standard, DSS), ANSI X9.30 + +=head1 SEE ALSO + +L<dsa(3)|dsa(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, +L<DSA_do_sign(3)|DSA_do_sign(3)> + +=head1 HISTORY + +DSA_sign() and DSA_verify() are available in all versions of SSLeay. +DSA_sign_setup() was added in SSLeay 0.8. + +=cut |