- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- HISTORY

# 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 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.

# SEE ALSO

dsa, ERR_get_error, rand, DSA_SIG_new, DSA_sign

# HISTORY

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