DSA_DO_SIGN(3)             Library Functions Manual             DSA_DO_SIGN(3)

NAME
     DSA_do_sign, DSA_do_verify - raw DSA signature operations

SYNOPSIS
     #include <openssl/dsa.h>

     DSA_SIG *
     DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);

     int
     DSA_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
         DSA *dsa);

DESCRIPTION
     DSA_do_sign() computes a digital signature on the dlen byte message
     digest dgst using the private key dsa and returns it in a newly allocated
     DSA_SIG structure.

     DSA_sign_setup(3) may be used to precompute part of the signing operation
     in case signature generation is time-critical.

     DSA_do_verify() verifies that the signature sig matches a given message
     digest dgst of size dgst_len.  dsa is the signer's public key.

RETURN VALUES
     DSA_do_sign() returns the signature or NULL on error.  DSA_do_verify()
     returns 1 for a valid signature, 0 for an incorrect signature, and -1 on
     error.  The error codes can be obtained by ERR_get_error(3).

SEE ALSO
     DSA_get0_key(3), DSA_meth_set_sign(3), DSA_new(3), DSA_SIG_new(3),
     DSA_sign(3)

HISTORY
     DSA_do_sign() and DSA_do_verify() first appeared in OpenSSL 0.9.3 and
     have been available since OpenBSD 2.6.

Linux 6.8.2-arch2-1              June 10, 2019             Linux 6.8.2-arch2-1