Ruby

Verify XML Signature with External URL References

See more XML Digital Signatures Examples

Demonstrates how to verify an XML digital signature that includes references to URLs where the data to be digested is on a web server. Ruby

require 'chilkat'

success = false

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

# The signed XML we wish to verify contains external references such as this:

#     <ds:Reference Id="xmldsig-e7ae7ce2-9133-4d56-bd97-0a6aef738cc2-ref0" URI="https://www.chilkatsoft.com/images/starfish.jpg">
#       <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
#       <ds:DigestValue>AOU810yJV5Np/DnO29qpObqiTSTTCDvxGsX5ayiTYXI=</ds:DigestValue>
#     </ds:Reference>
#     <ds:Reference Id="xmldsig-e7ae7ce2-9133-4d56-bd97-0a6aef738cc2-ref1" URI="https://www.chilkatsoft.com/hamlet.xml">
#       <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
#       <ds:DigestValue>4sRRyWOzC7EOic4fQ9+Op1pa10DbgoBGjBvkq09LZmE=</ds:DigestValue>
#     </ds:Reference>

verifier = Chilkat::CkXmlDSig.new()
http = Chilkat::CkHttp.new()

# First load the signed XML
sbSignedXml = Chilkat::CkStringBuilder.new()
success = sbSignedXml.LoadFile("qa_data/xml_dsig_verify/signedWithExternalUrlRefs.xml","utf-8")
if (success == false)
    print "Failed to load signed XML." + "\n";
    exit
end

success = verifier.LoadSignatureSb(sbSignedXml)
if (success == false)
    print verifier.lastErrorText() + "\n";
    exit
end

# Iterate over each reference.  If it is an external URL reference, download the data and provide it to the verifier.
sbRefUri = Chilkat::CkStringBuilder.new()
bd = Chilkat::CkBinData.new()
numRefs = verifier.get_NumReferences()
i = 0
while i < numRefs
    if (verifier.IsReferenceExternal(i) == true)
        sbRefUri.Clear()
        sbRefUri.Append(verifier.referenceUri(i))
        if (sbRefUri.StartsWith("https://",false) == true)
            print "External URL Reference: " + sbRefUri.getAsString() + "\n";

            # Download the data at the URL and provide to the verifier.
            success = http.DownloadBd(sbRefUri.getAsString(),bd)
            if (success == false)
                print http.lastErrorText() + "\n";
                exit
            end

            success = verifier.SetRefDataBd(i,bd)
            if (success == false)
                print verifier.lastErrorText() + "\n";
                exit
            end

        end

    end

    i = i + 1
end

# Now that we have the external data, verify the signature..
bVerified = verifier.VerifySignature(true)
if (bVerified == false)
    print verifier.lastErrorText() + "\n";
end

print "Signature verified = " + bVerified.to_s() + "\n";