Provided by: libcrypt-dsa-perl_1.17-4_all
Crypt::DSA - DSA Signatures and Key Generation
use Crypt::DSA; my $dsa = Crypt::DSA->new; my $key = $dsa->keygen( Size => 512, Seed => $seed, Verbosity => 1 ); my $sig = $dsa->sign( Message => "foo bar", Key => $key ); my $verified = $dsa->verify( Message => "foo bar", Signature => $sig, Key => $key, );
Crypt::DSA is an implementation of the DSA (Digital Signature Algorithm) signature verification system. The implementation itself is pure Perl, although the heavy-duty mathematics underneath are provided by the Math::Pari library. This package provides DSA signing, signature verification, and key generation.
The Crypt::DSA public interface is similar to that of Crypt::RSA. This was done intentionally. Crypt::DSA->new Constructs a new Crypt::DSA object. At the moment this isn't particularly useful in itself, other than being the object you need to do much else in the system. Returns the new object. $key = $dsa->keygen(%arg) Generates a new set of DSA keys, including both the public and private portions of the key. %arg can contain: · Size The size in bits of the p value to generate. The q and g values are always 160 bits each. This argument is mandatory. · Seed A seed with which q generation will begin. If this seed does not lead to a suitable prime, it will be discarded, and a new random seed chosen in its place, until a suitable prime can be found. This is entirely optional, and if not provided a random seed will be generated automatically. · Verbosity Should be either 0 or 1. A value of 1 will give you a progress meter during p and q generation--this can be useful, since the process can be relatively long. The default is 0. $signature = $dsa->sign(%arg) Signs a message (or the digest of a message) using the private portion of the DSA key and returns the signature. The return value--the signature--is a Crypt::DSA::Signature object. %arg can include: · Digest A digest to be signed. The digest should be 20 bytes in length or less. You must provide either this argument or Message (see below). · Key The Crypt::DSA::Key object with which the signature will be generated. Should contain a private key attribute (priv_key). This argument is required. · Message A plaintext message to be signed. If you provide this argument, sign will first produce a SHA1 digest of the plaintext, then use that as the digest to sign. Thus writing my $sign = $dsa->sign(Message => $message, ... ); is a shorter way of writing use Digest::SHA qw( sha1 ); my $sig = $dsa->sign(Digest => sha1( $message ), ... ); $verified = $dsa->verify(%arg) Verifies a signature generated with sign. Returns a true value on success and false on failure. %arg can contain: · Key Key of the signer of the message; a Crypt::DSA::Key object. The public portion of the key is used to verify the signature. This argument is required. · Signature The signature itself. Should be in the same format as returned from sign, a Crypt::DSA::Signature object. This argument is required. · Digest The original signed digest whose length is less than or equal to 20 bytes. Either this argument or Message (see below) must be present. · Message As above in sign, the plaintext message that was signed, a string of arbitrary length. A SHA1 digest of this message will be created and used in the verification process.
Add ability to munge format of keys. For example, read/write keys from/to key files (SSH key files, etc.), and also write them in other formats.
Bugs should be reported via the CPAN bug tracker at <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Crypt-DSA> For other issues, contact the author.
Benjamin Trott <email@example.com>
Except where otherwise noted, Crypt::DSA is Copyright 2006 - 2011 Benjamin Trott. Crypt::DSA is free software; you may redistribute it and/or modify it under the same terms as Perl itself.