Dart
Dart
Verify Multiple Signatures in XML
See more XML Digital Signatures Examples
Demonstrates how to verify multiple signatures within a single XML document.Chilkat Dart Downloads
import 'package:chilkat/chilkat.dart';
void main() {
// 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
final http = CkHttp();
final sbXml = CkStringBuilder();
try {
http.quickGetSb('https://www.chilkatsoft.com/exampleData/document.signed.bes.cs.xml', sbXml);
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
// Load the XML containing the signature to be verified.
final verifier = CkXmlDSig();
try {
verifier.loadSignatureSb(sbXml);
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
// How many Signatures exist in this XML?
print('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...
var i = 0;
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;
final verifyReferenceDigests = true;
// The quick way to validate all references and the signature over the SignedInfo
// is to call VerifySignature with verifyReferenceDigests equal to true.
var verified = true;
try {
verifier.verifySignature(verifyReferenceDigests);
} on ChilkatException {
verified = false;
}
print('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.
final numReferences = verifier.numReferences;
print(' number of references: $numReferences');
var j = 0;
while (j < numReferences) {
// Get information about the Jth reference in the Ith signature.
print(' reference $j:');
// Is this a same-document or external reference?
print(' is external: ${verifier.isReferenceExternal(j)}');
// For external references, the URI could be used by an application to fetch the referenced data...
print(' uri: ${verifier.referenceUri(j)}');
j++;
}
// 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.
final keyInfoXml = verifier.getKeyInfo();
print(' key info: ${keyInfoXml.getXml()}');
i++;
}
// 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>
//
//
}