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Math::PARI and Crypt::RSA

by shug94 (Sexton)
on Oct 26, 2009 at 10:36 UTC ( #803235=perlquestion: print w/ replies, xml ) Need Help??
shug94 has asked for the wisdom of the Perl Monks concerning the following question:

I have been playing with Crypt::RSA for a while, and I am having some problems getting it to work properly. I am trying to use an external key.
I am generating the private key and writing it to file using the following code:
#!/usr/bin/perl use strict; use Crypt::RSA; print "RSA tester\n"; my $infoToSign = "blah"; my $privateKey = 5; my $rsa = new Crypt::RSA; my ($public, $private) = $rsa->keygen ( Identity => 'RBSClient', Size => 1024, Password => 'passw0rd', Verbosity => 1, ) or die $rsa->errstr(); $private->write( Filename => 'working.private'); $public->write( Filename => 'working.public');
This produces the following private key file (I have reduced the length of the streams of numbers for brevity):
$VAR1 = bless( { 'Version' => '1.99', 'Checked' => 0, 'Identity' => 'RBSClient', 'private_encrypted' => bless( { '_phi' => 'Blowfish d +u2N7P83ABQ cFDt9/0y7IQ 53616c7465645f5f...', '_n' => 'Blowfish Mqm +rxVsrrHbWw RNNCruuuw 53616c7465645f5f658f18eec5ea...', '_q' => 'Blowfish qC0 +F63YxDS8KW LUGDfCMcg 53616c7465645f5f...', '_p' => 'Blowfish sNm +IMm9AuxeF8 uhD/JHszA 53616c7465645f5f...', '_dp' => 'Blowfish p2 +z6NZBV1grw lhJye/R4sw 53616c7465645f5f...', '_u' => 'Blowfish Huh +TLQDF0TEzo Ln7exXdiw 53616c7465645f5f...', '_dq' => 'Blowfish Yf +/aS7U0nI1U GYvagT4J3A 53616c7465645f5f...', '_d' => 'Blowfish SXE +nuMNvxaF2y JFTalOnbQ 53616c7465645f5f...', '_e' => 'Blowfish EzK +9HcfPA2zj4 wouO9lMww 53616c7465645f5f...' }, 'Tie::EncryptedHash' + ), 'Cipher' => 'Blowfish' }, 'Crypt::RSA::Key::Private' );
I then try to create a private key object to sign with, loading from file in the following way:
#!/perl/bin/perl package RBS_PrivateKeyWrapper; use strict; sub getPrivateKey() { my $privateKeyFilename = '/var/www/html/certificates/working.private +'; my $privateKey = getPrivateKeyPerlRSAEncoded($privateKeyFilename); return $privateKey; } sub getPrivateKeyPerlRSAEncoded($) { my ($privateKeyFilename) = @_; my $privateKey = new Crypt::RSA::Key::Private( Filename => $privateKeyFilename ); return $privateKey; } 1;
Up until this point I know that it works fine, because if I comment out the next step there is no problem. However I do actually need to sign the data. I try to sign the data as shown below:
#!/perl/bin/perl use Crypt::RSA; use RBS_PrivateKeyWrapper; my $privateKey = RBS_PrivateKeyWrapper::getPrivateKey(); my $signature = getSignatures($privateKey, $binarySecurityToken, $time +stamp, $content); print $signature; #### sub getSignature($$) { my ($privateKey, $infoToSign) = @_; my $rsa = new Crypt::RSA; my $signatureValue = $rsa->sign( Message => $infoToSign, Key => $privateKey,); return $signatureValue; }
This seems like it should work, but it does not. The errors I get seem to be associated with Crypt::RSA and Math::PARI not playing well together. I am getting the following error (which I do not get if I do not try to sign the data):
[Mon Oct 26 21:15:33 2009] [error] [client] PARI: *** +log is not meromorphic at 0. at /usr/lib/perl5/site_perl/5.8.8/i386-linux-thread +-multi/Mat h/ line 994.
I didn't know what meromorphic meant, so I looked it up and it seems to be saying that you cannot get the logarithm of 0, as there could be infinite values. I think this is due to line 77 of, which is as follows:
sub bitsize ($) { return pari2num(floor(Math::Pari::log(shift)/Matth::Pari::log(2)) + +1); }
So clearly a value of 0 is being passed into this function, and it is not happy with it. Also, the actual line of that is failing is 994, the '&$1;' line listed below (this seems to be some kind of function loading method, but I am unsure):
sub AUTOLOAD { $AUTOLOAD =~ /^(?:Math::Pari::)?(.*)/; # warn "Autoloading $1...\n"; # exit 4 if $1 eq 'loadPari'; my $cv = loadPari($1); # goto &$cv; # goto &$AUTOLOAD; # &$cv; &$1; # &$AUTOLOAD; }
As always, any help would be appreciated. I have Pari and GP installed on my machine, at the latest stable version. I am not sure why this is not working. Has anyone else got any experience with using Crypt::RSA? Do you have any ideas on how to load keys from external files and use them? Or any other ways to do this?

Hopefully someone can help,


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Re: Math::PARI and Crypt::RSA
by Anonymous Monk on Oct 26, 2009 at 11:43 UTC
    It happens when password is missing
    #!/usr/bin/perl -- use strict; use warnings; use File::Spec; use Crypt::RSA; Main(@ARGV); exit(0); sub Main { my $thisf = File::Spec->rel2abs(__FILE__); my $fprivate = "$thisf-testkey.private"; my $fpublic = "$thisf-testkey.public"; print "RSA tester ($thisf)\n"; my $infoToSign = "blah"; my $privateKey = 5; my $rsa = new Crypt::RSA; my ( $public, $private ); if ( -e $fpublic and -e $fprivate ) { print "reading $fprivate\n"; $private = new Crypt::RSA::Key::Private( Filename => $fprivate, @_ ? ( Password => 'password' ) : (), # NOTICE ARGV ); } else { print "generating keys\n"; ( $public, $private ) = $rsa->keygen( Identity => 'RBSClient', Size => 1024, Password => 'password', ) or die $rsa->errstr(); $private->write( Filename => $fprivate ); $public->write( Filename => $fpublic ); } print "signing $infoToSign\n"; my $signature = $rsa->sign( Message => $infoToSign, Key => $private, Armour => 1, ) || die $rsa->errstr(); print "$signature \n"; } __END__ $ perl RSA tester (~/tmp/ generating keys signing blah PARI: *** negative exponent in glog. at ~/lib/Crypt/RSA/DataFormat line 77. $ $ perl RSA tester (~/tmp/ reading ~/tmp/ signing blah PARI: *** negative exponent in glog. at ~/lib/MSWin32-x86-multi-th +read/Math/ line 994. $ perl asdf RSA tester (~/tmp/ reading ~/tmp/ signing blah -----BEGIN RSA SIGNATURE----- Version: 1.99 Scheme: Crypt::RSA::SS::PSS OQAxMjgAU2lnbmF0dXJlU7UxMIX136kFP+o3o7Pf5orq6jeCJWI7qG/uRqCwFgAoUc/LUR +9jsmBM B1Wl6krjm/98qTYUNgNNWgApxsfTFu23jL3LBbrKH50fNql9YuElxYdER0kyFJgX61xmrg +ivfbm1 Vim4LMMoCSJq2qyhCOEcA1q3zg/p+6U5/Zg8Lbg= =ufjanyZlBik+n/N3tWigfw== -----END RSA SIGNATURE----- $
      This was incredibly helpful and fixed all of my problems. Thankyou very much!
Re: Math::PARI and Crypt::RSA
by proceng (Scribe) on Oct 26, 2009 at 20:04 UTC
    Was this a typo?

    my $signature = getSignatures($privateKey, $binarySecurityToken, $time ++stamp, $content); #==here it's getSignatures print $signature; #### sub getSignature($$) #==here it's <b>getSignature</b> {
    In case it wasn't clear what I meant, the sub is defined as "getSignature($$)", while you called it as "getSignatures" (note the missing s at the end of the function name.
    Otherwise, the previous response should get you there :-)
      No, not a typo, I just didn't include a getSignatures function in my question which calls getSignature a bunch of times based on what inputs we have.

      Sorry for not being clear

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