DSA_do_sign(3)

     DSA_do_sign(3)         0.9.6h (2002-09-25)         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 len 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 len.  dsa is the signer's
          public key.

     RETURN VALUES
          DSA_do_sign() returns the signature, 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(3), ERR_get_error(3), rand(3), DSA_SIG_new(3),
          DSA_sign(3)

     HISTORY
          DSA_do_sign() and DSA_do_verify() were added in OpenSSL
          0.9.3.

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