NAME
Crypt::OpenSSL::DSA - Digital Signature Algorithm using OpenSSL
SYNOPSIS
use Crypt::OpenSSL::DSA;
# generate keys and write out to PEM files
my $dsa = Crypt::OpenSSL::DSA->generate_parameters( 512 );
$dsa->generate_key;
$dsa->write_pub_key( $filename );
$dsa->write_priv_key( $filename );
# using keys from PEM files
my $dsa_priv = Crypt::OpenSSL::DSA->read_priv_key( $filename );
my $sig = $dsa_priv->sign($message);
my $dsa_pub = Crypt::OpenSSL::DSA->read_pub_key( $filename );
my $valid = $dsa_pub->verify($message, $sig);
# using keys from PEM strings
my $dsa_priv = Crypt::OpenSSL::DSA->read_priv_key_str( $key_string );
my $sig = $dsa_priv->sign($message);
my $dsa_pub = Crypt::OpenSSL::DSA->read_pub_key_str( $key_string );
my $valid = $dsa_pub->verify($message, $sig);DESCRIPTION
Crypt::OpenSSL::DSA implements the DSA (Digital Signature Algorithm) signature verification system.
It is a thin XS wrapper to the DSA functions contained in the OpenSSL crypto library, located at http://www.openssl.org
CLASS METHODS
- $dsa = Crypt::OpenSSL::DSA->generate_parameters( $bits, $seed );
-
Returns a new DSA object and generates the p, q and g parameters necessary to generate keys.
bits is the length of the prime to be generated; the DSS allows a maximum of 1024 bits.
- $dsa = Crypt::OpenSSL::DSA->read_params( $filename );
-
Reads in a parameter PEM file and returns a new DSA object with the p, q and g parameters necessary to generate keys.
- $dsa = Crypt::OpenSSL::DSA->read_pub_key( $filename );
-
Reads in a public key PEM file and returns a new DSA object that can be used to verify DSA signatures.
- $dsa = Crypt::OpenSSL::DSA->read_priv_key( $filename );
-
Reads in a private key PEM file and returns a new DSA object that can be used to sign messages.
- $dsa = Crypt::OpenSSL::DSA->read_pub_key_str( $key_string );
-
Reads in a public key PEM string and returns a new DSA object that can be used to verify DSA signatures. The string should include the -----BEGIN...----- and -----END...----- lines.
- $dsa = Crypt::OpenSSL::DSA->read_priv_key_str( $key_string );
-
Reads in a private key PEM string and returns a new DSA object that can be used to sign messages. The string should include the -----BEGIN...----- and -----END...----- lines.
OBJECT METHODS
- $dsa->generate_key;
-
Generates private and public keys, assuming that $dsa is the return value of generate_parameters.
- $sig = $dsa->sign( $message );
-
Signs $message, returning the signature. Note that $meesage cannot exceed 20 characters in length.
$dsa is the signer's private key.
- $sig_obj = $dsa->do_sign( $message );
-
Similar to
sign, but returns a Crypt::OpenSSL::DSA::Signature object. - $valid = $dsa->verify( $message, $sig );
-
Verifies that the $sig signature for $message is valid.
$dsa is the signer's public key.
Note: it croaks if the underlying library call returns error (-1).
- $valid = $dsa->do_verify( $message, $sig_obj );
-
Similar to
verify, but uses a Crypt::OpenSSL::DSA::Signature object.Note: it croaks if the underlying library call returns error (-1).
- $dsa->write_params( $filename );
-
Writes the parameters into a PEM file.
- $dsa->write_pub_key( $filename );
-
Writes the public key into a PEM file.
- $dsa->write_priv_key( $filename );
-
Writes the private key into a PEM file.
- $p = $dsa->get_p, $dsa->set_p($p)
-
Gets/sets the prime number in binary format.
- $q = $dsa->get_q, $dsa->set_q($q)
-
Gets/sets the subprime number (q | p-1) in binary format.
- $g = $dsa->get_g, $dsa->set_g($g)
-
Gets/sets the generator of subgroup in binary format.
- $pub_key = $dsa->get_pub_key, $dsa->set_pub_key($pub_key)
-
Gets/sets the public key (y = g^x) in binary format.
- $priv_key = $dsa->get_priv_key, $dsa->set_priv_key($priv_key)
-
Gets/sets the private key in binary format.
NOTES
Crpyt::DSA is a more mature Perl DSA module, but can be difficult to install, because of the Math::Pari requirement.
Comments, suggestions, and patches welcome.
AUTHOR
T.J. Mather, <tjmather@maxmind.com>
COPYRIGHT
Copyright (c) 2002 T.J. Mather. Crypt::OpenSSL::DSA is free software; you may redistribute it and/or modify it under the same terms as Perl itself.
Paid support is available from directly from the author of this package. Please see http://www.maxmind.com/app/opensourceservices for more details.
SEE ALSO
Crypt::OpenSSL::DSA::Signature