I was running into the exact same problem. So wrote a module that will handle this without the "namespace" errors.

Link here: XML::Sig::OO

Here is the slice of code you need to validate the xml:
use Net::SAML2::Protocol::Assertion;
use XML::Sig::OO;
use MIME::Base64;
 
# Lets assume we have a post binding response
my $saml_response=.....
 
my $xml=decode_base64($saml_response);
 
my $v=XML::Sig::OO->new(xml=>$xml,cacert=>'idp_cert.pem');
my $result=$v->validate;
die $result unless $result;
 
# we can now use the asertion knowing it was from our idp
my $assertion=Net::SAML2::Protocol::Assertion->new_from_xml(xml=>$xml)

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In reply to Re^2: XML Signature Validation in Perl by akalinux
in thread XML Signature Validation in Perl by chora_sid

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