Perl Requires Chilkat v11.0.0+

Verify Opaque Signature and Retrieve Signing Certificates

See more Digital Signatures Examples

Demonstrates how to verify a PCKS7 opaque digital signature (signed data), extract the original file/data, and then extract the certificate(s) that were used to sign. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

my $crypt = Chilkat2::Crypt2->new;

# Verify a PKCS7 signed-data (opaque signature) file and extract the original content to a file.
my $success = $crypt->VerifyP7M('qa_data/p7m/opaqueSig.p7', 'qa_output/originalData.dat');
if (!$success) {
    print $crypt->LastErrorText, "\n";
    exit;
}

# Alternatively, we can do it in memory...
my $binData = Chilkat2::BinData->new;
$success = $binData->LoadFile('qa_data/p7m/opaqueSig.p7');
# Your app should check for success, but we'll skip the check for brevity..

# If verified, the signature is unwrapped and binData is replaced with the original data that was signed.
$success = $crypt->OpaqueVerifyBd($binData);
if (!$success) {
    print $crypt->LastErrorText, "\n";
    exit;
}

# For our testing, we signed some text, so we can get it from the binData..
print "Original Data:\n";
print $binData->GetString('utf-8'), "\n";

# After any method call that verifies a signature, the crypt object will contain the certificate(s)
# that were used for signing (assuming the X.509 certs were available in the signature, which is typically the case).

# Get each signing certificate, and build the certificate chain for each.
my $cert = Chilkat2::Cert->new;
my $certChain = Chilkat2::CertChain->new;
my $numCerts = $crypt->NumSignerCerts;
my $i = 0;
while ($i < $numCerts) {
    $crypt->LastSignerCert($i, $cert);
    print $cert->SubjectDN, "\n";

    $success = $cert->BuildCertChain($certChain);
    if (!$success) {
        print $cert->LastErrorText, "\n";
        exit;
    }

    $i = $i + 1;
}