(Ruby) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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

dsig = Chilkat::CkXmlDSig.new()
sbXml = Chilkat::CkStringBuilder.new()

success = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8")
if (success != true)
    print "Failed to load XML file." + "\n";
    exit
end

success = dsig.LoadSignatureSb(sbXml)
if (success != true)
    print dsig.lastErrorText() + "\n";
    exit
end

# Get the KeyInfo XML.
# xmlKeyInfo is a CkXml
xmlKeyInfo = dsig.GetKeyInfo()
if (dsig.get_LastMethodSuccess() != true)
    print dsig.lastErrorText() + "\n";
    exit
end

print xmlKeyInfo.getXml() + "\n";
print "----" + "\n";

# Assuming the X509Certificate is in the KeyInfo, it will look like this:

#   <ds:KeyInfo Id="...">
#     <ds:KeyValue>
#     ...  
#     <ds:X509Data>
#       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
#     </ds:X509Data>
#   </ds:KeyInfo>
certBase64 = xmlKeyInfo.getChildContent("*:X509Data|*:X509Certificate")
if (xmlKeyInfo.get_LastMethodSuccess() != true)
    print "No X509Certificate found in the KeyInfo." + "\n";
    exit
end

# Load a certificate object w/ the base64.
cert = Chilkat::CkCert.new()
success = cert.LoadFromBase64(certBase64)
if (success != true)
    print cert.lastErrorText() + "\n";
    exit
end

# Examine the cert..
print "SubjectDN: " + cert.subjectDN() + "\n";
print "IssuerDN: " + cert.issuerDN() + "\n";
print "SerialNumber as Decimal: " + cert.serialDecimal() + "\n";