Document DSA and SHA.

New function BN_pseudo_rand().
Use BN_prime_checks_size(BN_num_bits(w)) rounds of Miller-Rabin when
generating DSA primes (why not use BN_is_prime()?)

1 files changed, 62 insertions, 0 deletions

diff --git a/doc/crypto/DSA_sign.pod b/doc/crypto/DSA_sign.pod
new file mode 100644
index 0000000000..e064fd1c42
--- /dev/null
+++ b/doc/crypto/DSA_sign.pod
@@ -0,0 +1,62 @@
+=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.
+
+=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(3)|err(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