B4X
B4X
Verify Multiple Signatures in XML
See more XML Digital Signatures Examples
Demonstrates how to verify multiple signatures within a single XML document.Chilkat B4X Downloads
Dim success As Boolean = False
' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.
' A sample XML file containing multiple signatures is available at:
' https://www.chilkatsoft.com/exampleData/document.signed.bes.cs.xml
Dim http As ChilkatHttp
http.Initialize("http")
Dim sbXml As ChilkatStringBuilder
sbXml.Initialize
success = http.QuickGetSb("https://www.chilkatsoft.com/exampleData/document.signed.bes.cs.xml", sbXml)
If success <> True Then
Log(http.LastErrorText)
Return
End If
' Load the XML containing the signature to be verified.
Dim verifier As ChilkatXmlDSig
verifier.Initialize
success = verifier.LoadSignatureSb(sbXml)
If success <> True Then
Log(verifier.LastErrorText)
Return
End If
' How many Signatures exist in this XML?
Log("Number of XML signatures = " & verifier.NumSignatures)
' Let's show the XML nicely indented, so we can make sense of it.
' Loading the XML into an XML parser and re-emitting with nice formatting
' changes whitespace that breaks the signatures. We're only doing this
' for the example to examine this XML, which contains 2 ds:Signature's
' and each signature has multiple references.
' This is what we have:
' (scroll down to continue with this example..)
' <?xml version="1.0" encoding="UTF-8" ?>
' <collection Id="root">
' <album>
' <title>Questions, unanswered</title>
' <artist>Steve and the flubberblubs</artist>
' <year>1989</year>
' <t:tracks xmlns:t="http://test.xades4j/tracks">
' <t:song length="4:05" tracknumber="1">
' <t:title>What do you know?</t:title>
' <t:artist>Steve and the flubberblubs</t:artist>
' <t:lastplayed>2006-10-17-08:31</t:lastplayed>
' </t:song>
' <t:song length="3:45" tracknumber="2">
' <t:title>Who do you know?</t:title>
' <t:artist>Steve and the flubberblubs</t:artist>
' <t:lastplayed>2006-10-17-08:35</t:lastplayed>
' </t:song>
' <t:song length="5:14" tracknumber="3">
' <t:title>When do you know?</t:title>
' <t:artist>Steve and the flubberblubs</t:artist>
' <t:lastplayed>2006-10-17-08:39</t:lastplayed>
' </t:song>
' <t:song length="4:19" tracknumber="4">
' <t:title>Do you know?</t:title>
' <t:artist>Steve and the flubberblubs</t:artist>
' <t:lastplayed>2006-10-17-08:44</t:lastplayed>
' </t:song>
' </t:tracks>
' </album>
' <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Id="xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad">
' <ds:SignedInfo>
' <ds:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
' <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />
' <ds:Reference Id="xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-ref0" URI="#root">
' <ds:Transforms>
' <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
' </ds:Transforms>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>rD/g8soqKz8EiPUBhEWfcQacS0ta4ULHX3dKMEH6ZoQ=</ds:DigestValue>
' </ds:Reference>
' <ds:Reference Type="http://uri.etsi.org/01903#SignedProperties" URI="#xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-signedprops">
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>pfrrRjkGNPiRF2Bjuj3IJTGSEFYc2PDs6FCNAUJOu8E=</ds:DigestValue>
' </ds:Reference>
' </ds:SignedInfo>
' <ds:SignatureValue Id="xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-sigvalue">Vb/2ay4rX9cytiRCmBkgRkE4d0E05nkM412CwOHvTagCXPZZ2B2ifbmrQznTEU6Jz0dF65j5kU7C
' bYK+9fMKB0lmqx2kUdWeBa30Rl/3ELKWKOLeDFN91zC3q4a6dtzQGwBidWex+2dO8Z69sBd2aTS6
' S6nyGs53kTspDHfBeyg=</ds:SignatureValue>
' <ds:KeyInfo>
' <ds:X509Data>
' <ds:X509Certificate>MIICbTCCAdqgAwIBAgIQpkK0uals+ItHxBlpJuypOTAJBgUrDgMCHQUAMD8xCzAJBgNVBAYTAlBU
' MQ0wCwYDVQQKEwRJU0VMMQswCQYDVQQLEwJDQzEUMBIGA1UEAxMLSXRlcm1lZGlhdGUwHhcNMTAw
' NjI1MTc1ODQ5WhcNMzkxMjMxMjM1OTU5WjBCMQswCQYDVQQGEwJQVDENMAsGA1UEChMESVNFTDEL
' MAkGA1UECxMCQ0MxFzAVBgNVBAMTDkx1aXMgR29uY2FsdmVzMIGfMA0GCSqGSIb3DQEBAQUAA4GN
' ADCBiQKBgQCpP9acMX69Dbg9ciMLFc5dm1tlpTY9OTNZ/EaCYoGVhh/3+DFgyIbEer6SA24hpREm
' AhNG9+Ca0AurDPPgb3aKWFY9pj1WcOctis0VsR0YvzqP+2IGFqKDCd7bXFvv2tI0dEvpdc0oO6PF
' Q02xvJG0kxQf44XljOCjUBU43jkJawIDAQABo28wbTBrBgNVHQEEZDBigBBdbbL4pDKLT56PpOpA
' /56toTwwOjELMAkGA1UEBhMCUFQxDTALBgNVBAoTBElTRUwxCzAJBgNVBAsTAkNDMQ8wDQYDVQQD
' EwZUZXN0Q0GCEN00x9qe7SuWQvpLK0/oay8wCQYFKw4DAh0FAAOBgQBSma8g9dQjiQo4WUljRRuG
' yMUVRyCqW/9oRz8+0EoLNR/AhrIlGqdNbqQ1BkncgNNdqMAus5VD34v/EhgrkgWN5fZajMpYsmcR
' Ahu4PzJ6hggAlWWMy245JwIYuV0s1Oi39GVTxVNOBIX//AONZlGWO4S2Psb1mqdZ99b/MugsaA==</ds:X509Certificate>
' </ds:X509Data>
' </ds:KeyInfo>
' <ds:Object>
' <xades:QualifyingProperties xmlns:xades="http://uri.etsi.org/01903/v1.3.2#" xmlns:xades141="http://uri.etsi.org/01903/v1.4.1#" Target="#xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad">
' <xades:SignedProperties Id="xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-signedprops">
' <xades:SignedSignatureProperties>
' <xades:SigningCertificate>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>4btVb5gQ5cdcNhGpvDSWQZabPQrR9jf1x8e3YF9Ajss=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=Itermediate,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-119284162484605703133798696662099777223</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>vm5QpbblsWV7fCYXotPhNTeCt4nk8cLFuF36L5RJ4Ok=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=TestCA,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-46248926895392336918291885380930606289</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>AUaN+IdhKQqxIVmEOrFwq+Dn22ebTkXJqD3BoOP/x8E=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=TestCA,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-99704378678639105802976522062798066869</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' </xades:SigningCertificate>
' <xades:SignerRole>
' <xades:ClaimedRoles>
' <xades:ClaimedRole>CounterSignature maniac</xades:ClaimedRole>
' </xades:ClaimedRoles>
' </xades:SignerRole>
' </xades:SignedSignatureProperties>
' </xades:SignedProperties>
' <xades:UnsignedProperties>
' <xades:UnsignedSignatureProperties>
' <xades:CounterSignature>
' <ds:Signature Id="xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c" xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
' <ds:SignedInfo>
' <ds:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
' <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />
' <ds:Reference Id="xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c-ref0" URI="#xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-sigvalue">
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>Nr5JKCScyqjKWneJw2AC6YmdU/2JZA5Pj40fkVCFbL4=</ds:DigestValue>
' </ds:Reference>
' <ds:Reference Type="http://uri.etsi.org/01903#SignedProperties" URI="#xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c-signedprops">
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>PJWDlPFdx4TJ5AXT3nIbFa2euboYGM7bpuBmol4nKSQ=</ds:DigestValue>
' </ds:Reference>
' </ds:SignedInfo>
' <ds:SignatureValue Id="xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c-sigvalue">MCcli4l5rAsGeJX2gOmoYDIAXnbszmRwOH94y7kHnpxCwGwoVrCaLSONtgKEy8mj9Ehqa/R5Dj5g
' DgC77VkNIaRKD613JMnbsaqZ7PD0iVivLvBkasTch4PX92UEbk8EvCgzxvhlgN+L6zSLsv65sFcR
' lFUGluMtzrqlDKvts38=</ds:SignatureValue>
' <ds:KeyInfo>
' <ds:X509Data>
' <ds:X509Certificate>MIICbTCCAdqgAwIBAgIQpkK0uals+ItHxBlpJuypOTAJBgUrDgMCHQUAMD8xCzAJBgNVBAYTAlBU
' MQ0wCwYDVQQKEwRJU0VMMQswCQYDVQQLEwJDQzEUMBIGA1UEAxMLSXRlcm1lZGlhdGUwHhcNMTAw
' NjI1MTc1ODQ5WhcNMzkxMjMxMjM1OTU5WjBCMQswCQYDVQQGEwJQVDENMAsGA1UEChMESVNFTDEL
' MAkGA1UECxMCQ0MxFzAVBgNVBAMTDkx1aXMgR29uY2FsdmVzMIGfMA0GCSqGSIb3DQEBAQUAA4GN
' ADCBiQKBgQCpP9acMX69Dbg9ciMLFc5dm1tlpTY9OTNZ/EaCYoGVhh/3+DFgyIbEer6SA24hpREm
' AhNG9+Ca0AurDPPgb3aKWFY9pj1WcOctis0VsR0YvzqP+2IGFqKDCd7bXFvv2tI0dEvpdc0oO6PF
' Q02xvJG0kxQf44XljOCjUBU43jkJawIDAQABo28wbTBrBgNVHQEEZDBigBBdbbL4pDKLT56PpOpA
' /56toTwwOjELMAkGA1UEBhMCUFQxDTALBgNVBAoTBElTRUwxCzAJBgNVBAsTAkNDMQ8wDQYDVQQD
' EwZUZXN0Q0GCEN00x9qe7SuWQvpLK0/oay8wCQYFKw4DAh0FAAOBgQBSma8g9dQjiQo4WUljRRuG
' yMUVRyCqW/9oRz8+0EoLNR/AhrIlGqdNbqQ1BkncgNNdqMAus5VD34v/EhgrkgWN5fZajMpYsmcR
' Ahu4PzJ6hggAlWWMy245JwIYuV0s1Oi39GVTxVNOBIX//AONZlGWO4S2Psb1mqdZ99b/MugsaA==</ds:X509Certificate>
' </ds:X509Data>
' </ds:KeyInfo>
' <ds:Object>
' <xades:QualifyingProperties Target="#xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c" xmlns:xades="http://uri.etsi.org/01903/v1.3.2#" xmlns:xades141="http://uri.etsi.org/01903/v1.4.1#">
' <xades:SignedProperties Id="xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c-signedprops">
' <xades:SignedSignatureProperties>
' <xades:SigningTime>2012-10-13T14:26:18.783+01:00</xades:SigningTime>
' <xades:SigningCertificate>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>4btVb5gQ5cdcNhGpvDSWQZabPQrR9jf1x8e3YF9Ajss=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=Itermediate,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-119284162484605703133798696662099777223</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>vm5QpbblsWV7fCYXotPhNTeCt4nk8cLFuF36L5RJ4Ok=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=TestCA,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-46248926895392336918291885380930606289</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' <xades:Cert>
' <xades:CertDigest>
' <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />
' <ds:DigestValue>AUaN+IdhKQqxIVmEOrFwq+Dn22ebTkXJqD3BoOP/x8E=</ds:DigestValue>
' </xades:CertDigest>
' <xades:IssuerSerial>
' <ds:X509IssuerName>CN=TestCA,OU=CC,O=ISEL,C=PT</ds:X509IssuerName>
' <ds:X509SerialNumber>-99704378678639105802976522062798066869</ds:X509SerialNumber>
' </xades:IssuerSerial>
' </xades:Cert>
' </xades:SigningCertificate>
' </xades:SignedSignatureProperties>
' </xades:SignedProperties>
' </xades:QualifyingProperties>
' </ds:Object>
' </ds:Signature>
' </xades:CounterSignature>
' </xades:UnsignedSignatureProperties>
' </xades:UnsignedProperties>
' </xades:QualifyingProperties>
' </ds:Object>
' </ds:Signature>
' </collection>
'
' When I look at the complicated XML above, there are specific things I look at to get a handle
' on the situation.
'
' 1) Does the signature already embed the public keys required for verification?
' Within each <ds:Signature>, look for the <ds:KeyInfo>. In this case, I can see that
' each signature contains the full X.509 certificate needed to verify (<ds:KeyInfo><ds:X509Data><ds:X509Certificate>).
' This means that Chilkat will automatically use the public keys contained within the base64 certificates
' already present in the signature.
'
' 2) Look at each <ds:Reference> within each <ds:Signature>. Do the URI attribute values begin with "#"?
' If so, then these are same-document references, and there's no need to explicitly fetch external data for reference verification.
' Chilkat can automatically validate each same-document Reference.
'
' So it turns out that this seemingly formidable XML document is easy to verify...
' Here we go...
Dim i As Int = 0
Do While i < verifier.NumSignatures
' The Selector property is used to set our context to the Nth signature.
' For example, if VerifySignature is called when Selector = 0, then the 1st signature is verified.
' If VerifySignature is called when Selector = 1, then the 2nd signature is verified, and so on.
verifier.Selector = i
Dim verifyReferenceDigests As Boolean = True
' The quick way to validate all references and the signature over the SignedInfo
' is to call VerifySignature with verifyReferenceDigests equal to True.
Dim verified As Boolean = verifier.VerifySignature(verifyReferenceDigests)
Log("Signature " & (i + 1) & " and all reference digests verified = " & verified)
' We can also get information about each signature.
' For example, we could get information about each Reference...
' The NumReferences property returns the number of references for the Signature indicated by the Selector property.
Dim numReferences As Int = verifier.NumReferences
Log(" number of references: " & numReferences)
Dim j As Int = 0
Do While j < numReferences
' Get information about the Jth reference in the Ith signature.
Log(" reference " & j & ":")
' Is this a same-document or external reference?
Log(" is external: " & verifier.IsReferenceExternal(j))
' For external references, the URI could be used by an application to fetch the referenced data...
Log(" uri: " & verifier.ReferenceUri(j))
j = j + 1
Loop
' We could also get the KeyInfo for each Signature, which might be needed if we need to
' load and set a public key that is not physically present within the KeyInfo already.
Dim keyInfoXml As ChilkatXml = verifier.GetKeyInfo
Log(" key info: " & keyInfoXml.GetXml)
i = i + 1
Loop
' Here's the output of this example:
' Number of XML signatures = 2
' Signature 1 and all reference digests verified = True
' number of references: 2
' reference 0:
' is external: False
' uri: #root
' reference 1:
' is external: False
' uri: #xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-signedprops
' key info:
' <ds:KeyInfo>
' <ds:X509Data>
' <ds:X509Certificate>
' MIICbTCCAdqgAwIBAgIQpkK0uals+ItHxBlpJuypOTAJBgUrDgMCHQUAMD8xCzAJBgNVBAYTAlBU
' MQ0wCwYDVQQKEwRJU0VMMQswCQYDVQQLEwJDQzEUMBIGA1UEAxMLSXRlcm1lZGlhdGUwHhcNMTAw
' NjI1MTc1ODQ5WhcNMzkxMjMxMjM1OTU5WjBCMQswCQYDVQQGEwJQVDENMAsGA1UEChMESVNFTDEL
' MAkGA1UECxMCQ0MxFzAVBgNVBAMTDkx1aXMgR29uY2FsdmVzMIGfMA0GCSqGSIb3DQEBAQUAA4GN
' ADCBiQKBgQCpP9acMX69Dbg9ciMLFc5dm1tlpTY9OTNZ/EaCYoGVhh/3+DFgyIbEer6SA24hpREm
' AhNG9+Ca0AurDPPgb3aKWFY9pj1WcOctis0VsR0YvzqP+2IGFqKDCd7bXFvv2tI0dEvpdc0oO6PF
' Q02xvJG0kxQf44XljOCjUBU43jkJawIDAQABo28wbTBrBgNVHQEEZDBigBBdbbL4pDKLT56PpOpA
' /56toTwwOjELMAkGA1UEBhMCUFQxDTALBgNVBAoTBElTRUwxCzAJBgNVBAsTAkNDMQ8wDQYDVQQD
' EwZUZXN0Q0GCEN00x9qe7SuWQvpLK0/oay8wCQYFKw4DAh0FAAOBgQBSma8g9dQjiQo4WUljRRuG
' yMUVRyCqW/9oRz8+0EoLNR/AhrIlGqdNbqQ1BkncgNNdqMAus5VD34v/EhgrkgWN5fZajMpYsmcR
' Ahu4PzJ6hggAlWWMy245JwIYuV0s1Oi39GVTxVNOBIX//AONZlGWO4S2Psb1mqdZ99b/MugsaA==
' </ds:X509Certificate>
' </ds:X509Data>
' </ds:KeyInfo>
'
' Signature 2 and all reference digests verified = True
' number of references: 2
' reference 0:
' is external: False
' uri: #xmldsig-ff7d9ad7-f36d-4af0-b21a-7db2e840efad-sigvalue
' reference 1:
' is external: False
' uri: #xmldsig-7479045c-8083-49eb-9043-1ac2af4a759c-signedprops
' key info:
' <ds:KeyInfo>
' <ds:X509Data>
' <ds:X509Certificate>
' MIICbTCCAdqgAwIBAgIQpkK0uals+ItHxBlpJuypOTAJBgUrDgMCHQUAMD8xCzAJBgNVBAYTAlBU
' MQ0wCwYDVQQKEwRJU0VMMQswCQYDVQQLEwJDQzEUMBIGA1UEAxMLSXRlcm1lZGlhdGUwHhcNMTAw
' NjI1MTc1ODQ5WhcNMzkxMjMxMjM1OTU5WjBCMQswCQYDVQQGEwJQVDENMAsGA1UEChMESVNFTDEL
' MAkGA1UECxMCQ0MxFzAVBgNVBAMTDkx1aXMgR29uY2FsdmVzMIGfMA0GCSqGSIb3DQEBAQUAA4GN
' ADCBiQKBgQCpP9acMX69Dbg9ciMLFc5dm1tlpTY9OTNZ/EaCYoGVhh/3+DFgyIbEer6SA24hpREm
' AhNG9+Ca0AurDPPgb3aKWFY9pj1WcOctis0VsR0YvzqP+2IGFqKDCd7bXFvv2tI0dEvpdc0oO6PF
' Q02xvJG0kxQf44XljOCjUBU43jkJawIDAQABo28wbTBrBgNVHQEEZDBigBBdbbL4pDKLT56PpOpA
' /56toTwwOjELMAkGA1UEBhMCUFQxDTALBgNVBAoTBElTRUwxCzAJBgNVBAsTAkNDMQ8wDQYDVQQD
' EwZUZXN0Q0GCEN00x9qe7SuWQvpLK0/oay8wCQYFKw4DAh0FAAOBgQBSma8g9dQjiQo4WUljRRuG
' yMUVRyCqW/9oRz8+0EoLNR/AhrIlGqdNbqQ1BkncgNNdqMAus5VD34v/EhgrkgWN5fZajMpYsmcR
' Ahu4PzJ6hggAlWWMy245JwIYuV0s1Oi39GVTxVNOBIX//AONZlGWO4S2Psb1mqdZ99b/MugsaA==
' </ds:X509Certificate>
' </ds:X509Data>
' </ds:KeyInfo>
'
'