Assuming your perl script is a CGI script, sense you want to "export it from the browser".

Apache/mod_ssl provides a convenient method of extracting X.509 certificate data.

The ExportCertData option exports two additional environment variables: SSL_CLIENT_CERT and SSL_SERVER_CERT. These contain the PEM-encoded certificates of the server (always existing) and the client (only existing when client authentication is used). This can be used to import the certificates into CGI scripts.

Add +ExportCertData to SSLOptions and the PEM encoded client certificate and issuer certificate(s) will be added to %ENV. The issuing CA certs are named SSL_CLIENT_CERT_CHAIN_x 
<FilesMatch "\.(do|cgi|shtml|phtml|php)$">
  SSLOptions +StdEnvVars +ExportCertData
</FilesMatch>

[download]
Here is an example CGI that displays the PEM encoded cert info: 
#!/usr/bin/perl
use CGI qw(:standard);
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);
$|=1;
print header;
print start_html("X.509 Certificate Info");
if ( defined( $ENV{SSL_CLIENT_S_DN} ) ){
  print $ENV{SSL_CLIENT_CERT}, "<br />";
} else {
  print "ERROR: Client certificate not presented to webserver for auth
+entication";
}
print end_html;

[download]

In reply to Re: Help extracting public key from X509 .cer file by bcarroll
in thread Help extracting public key from X509 .cer file by boat73

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