Crypt::X509::CRL is an object oriented X.509 certificate revocation list parser with numerous methods for directly extracting information from certificate revocation lists.
To install this module type the following:
perl Makefile.PL make make test make install
This module requires:
Convert::ASN1
Crypt::X509::CRL - Parses an X.509 certificate revocation list
use Crypt::X509::CRL; $decoded = Crypt::X509::CRL->new( crl => $crl ); $subject_email = $decoded->subject_email; print "do not use after: ".gmtime($decoded->not_after)." GMT\n";
Crypt::X509::CRL parses X.509 certificate revocation lists. Methods are provided for accessing most CRL elements.
It is based on the generic ASN.1 module by Graham Barr, on the x509decode example by Norbert Klasen and contributions on the perl-ldap-dev-Mailinglist by Chriss Ridd. It is also based upon the works of Mike Jackson and Alexander Jung perl module Crypt::X509.
The following RFC 3280 Extensions are available (noted are the ones I have implemented).
Authority Key Identifier (implemented) CRL Number (implemented) Issuing Distribution Point (implemented) Issuer Alternative Name Delta CRL Indicator Freshest CRL (a.k.a. Delta CRL Distribution Point)
The following RFC 3280 CRL Entry Extensions are available (noted are the ones I have implemented).
Reason Code (implemented) Hold Instruction Code (implemented) Invalidity Date (implemented) Certificate Issuer
NOTE: The use of 'utcTime' in determining the revocation date of a given certificate is based on RFC 3280 for dates through the year 2049. Starting with dates in 2050 and beyond the RFC calls for revocation dates to be listed as 'generalTime'.
Creates and returns a parsed X.509 CRL hash, containing the parsed contents. The data is organised as specified in RFC 2459. By default only the first ASN.1 Layer is decoded. Nested decoding is done automagically through the data access methods.
A variable containing the DER formatted crl to be parsed (eg. as stored in certificateRevocationList;binary attribute in an LDAP-directory).
certificateRevocationList;binary
use Crypt::X509::CRL; use Data::Dumper; $decoded = Crypt::X509::CRL->new( crl => $crl ); print Dumper $decoded;
Returns the last error from parsing, undef when no error occured. This error is updated on deeper parsing with the data access methods.
undef
$decoded= Crypt::X509::CRL->new(crl => $crl); if ( $decoded->error ) { warn "Error on parsing Certificate Revocation List: ", $decoded->error; }
You can access all parsed data directly from the returned hash. For convenience the following data access methods have been implemented to give quick access to the most-used crl attributes.
Returns the certificate revocation list's version as an integer. Returns undef if the version is not specified, since it is an optional field in some cases.
0 = v1 1 = v2 2 = v3
Returns the certificate revocation list's version as a string value (ie 'v1', 'v2', or 'v3').
Returns either the utcTime or generalTime of the certificate revocation list's date of publication. Returns undef if not defined.
$decoded = Crypt::X509::CRL->new(crl => $crl); print "CRL was published at ", gmtime( $decoded->this_update ), " GMT\n";
Returns either the utcTime or generalTime of the certificate revocation list's date of expiration. Returns undef if not defined.
$decoded = Crypt::X509::CRL->new(crl => $crl); if ( $decoded->next_update < time() ) { warn "CRL has expired!"; }
Return's the certificate's signature in binary DER format.
Return's the length of the certificate's signature.
Returns the certificate's signature algorithm as an OID string.
$decoded = Crypt::X509::CRL->new(crl => $crl); print "CRL signature is encrypted with:", $decoded->signature_algorithm, "\n"; Example Output: CRL signature is encrypted with: 1.2.840.113549.1.1.5
Returns the signature encryption algorithm (e.g. 'RSA') as a string.
$decoded = Crypt::X509::CRL->new(crl => $crl); print "CRL signature is encrypted with:", $decoded->SigEncAlg, "\n"; Example Output: CRL signature is encrypted with: RSA
Returns the signature hashing algorithm (e.g. 'SHA1') as a string.
$decoded = Crypt::X509::CRL->new(crl => $crl); print "CRL signature is hashed with:", $decoded->SigHashAlg, "\n"; Example Output: CRL signature is encrypted with: SHA1
Returns a pointer to an array of strings building the DN of the certificate issuer (= the DN of the CA). Attribute names for the most common Attributes are translated from the OID-Numbers, unknown numbers are output verbatim.
$decoded = Crypt::X509::CRL->new( $crl ); print "CRL was issued by: ", join( ', ' , @{ $decoded->Issuer } ), "\n";
Returns the string value for issuer's common name (= the value with the OID 2.5.4.3 or in DN Syntax everything after CN=). Only the first entry is returned. undef if issuer contains no common name attribute.
CN=
Returns the string value for issuer's country (= the value with the OID 2.5.4.6 or in DN Syntax everything after C=). Only the first entry is returned. undef if issuer contains no country attribute.
C=
Returns the string value for issuer's state or province (= the value with the OID 2.5.4.8 or in DN Syntax everything after S=). Only the first entry is returned. undef if issuer contains no state attribute.
S=
Returns the string value for issuer's locality (= the value with the OID 2.5.4.7 or in DN Syntax everything after L=). Only the first entry is returned. undef if issuer contains no locality attribute.
L=
Returns the string value for issuer's organization (= the value with the OID 2.5.4.10 or in DN Syntax everything after O=). Only the first entry is returned. undef if issuer contains no organization attribute.
O=
Returns the string value for issuer's email address (= the value with the OID 1.2.840.113549.1.9.1 or in DN Syntax everything after E=). Only the first entry is returned. undef if issuer contains no email attribute.
E=
Returns the authority key identifier as a bit string.
$decoded = Crypt::X509::CRL->new( $crl ); my $s = unpack("H*" , $decoded->key_identifier); print "The Authority Key Identifier in HEX is: $s\n"; Example output: The Authority Key Identifier in HEX is: 86595f93caf32da620a4f9595a4a935370e792c9
Returns a pointer to an array of strings building the DN of the Authority Cert Issuer. Attribute names for the most common Attributes are translated from the OID-Numbers, unknown numbers are output verbatim. Returns undef if the extension is not set in the certificate.
$decoded = Crypt::X509::CRL->new($cert); print "Certificate was authorised by:", join( ', ', @{ $decoded->authorityCertIssuer } ), "\n";
Returns the authority's certificate serial number.
Returns the authority's ca.
Returns the authority's country.
Returns the authority's state.
Returns the authority's locality.
Returns the authority's organization.
Returns the authority's email.
Returns the CRL Number as an integer.
Returns the Issuing Distribution Points as a hash providing for the default values.
print "Issuing Distribution Points:\n"; my $IDPs = $decoded->IDPs; for my $key ( sort keys %{ $IDPs } ) { print "$key = "; if ( defined $IDPs->{ $key } ) { print $IDPs->{ $key }, "\n"; } else { print "undef\n"; } }
Issuing Distribution Points: critical = 1 directory_addr = CN=CRL2, O=U.S. Government, C=US indirectCRL = 0 onlyAttribCerts = 0 onlyCaCerts = 0 onlyUserCerts = 1 reasonFlags = undef url = undef
critical = 0 or 1 # default is FALSE directory_addr = CN=CR1,c=US # default is undef url = ldap://ldap.gov/cn=CRL1,c=US # default is undef onlyUserCerts = 0 or 1 # default is FALSE onlyCaCerts = 0 or 1 # default is FALSE onlyAttribCerts = 0 or 1 # default is FALSE indirectCRL = 0 or 1 # default is FALSE reasonFlags = BIT STRING # default is undef
Returns an array of hashes for the revoked certificates listed on the given CRL. The keys to the hash are the certificate serial numbers in decimal format.
print "Revocation List:\n"; my $rls = $decoded->revocation_list; my $count_of_rls = keys %{ $rls }; print "Found $count_of_rls revoked certificate(s) on this CRL.\n"; for my $key ( sort keys %{ $rls } ) { print "Certificate: ", DecimalToHex( $key ), "\n"; for my $extn ( sort keys %{ $rls->{ $key } } ) { if ( $extn =~ /date/i ) { print "\t$extn: ", ConvertTime( $rls->{ $key }{ $extn } ), "\n"; } else { print "\t$extn: ", $rls->{ $key }{ $extn }, "\n"; } } }
Revocation List: Found 1 revoked certificate(s) on this CRL. Certificate: 44 53 a0 f3 crlReason: keyCompromise invalidityDate: Wednesday, September 27, 2006 12:54:51 PM revocationDate: Wednesday, September 27, 2006 1:29:36 PM
See the examples of Convert::ASN1 and the <perl-ldap@perl.org> Mailing List. An example on how to load certificates can be found in t\Crypt-X509-CRL.t.
This module is based on the x509decode script, which was contributed to Convert::ASN1 in 2002 by Norbert Klasen.
It is also based on the Crypt::X509 perl module, which was contributed by Mike Jackson and Alexander Jung.
Duncan Segrest <cpan@gigageek.us> ,
Copyright (c) 2007 by Duncan Segrest <cpan@gigageek.us>.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.
To install Crypt::X509::CRL, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Crypt::X509::CRL
CPAN shell
perl -MCPAN -e shell install Crypt::X509::CRL
For more information on module installation, please visit the detailed CPAN module installation guide.