PureBasic
PureBasic
Create XML Signature with External XML Reference
See more XML Digital Signatures Examples
Demonstrates how to create an XML digital signature where the referenced data is external. In this case, the data is an XML file located at the following URL: https://www.chilkatsoft.com/data/helloWorld.xmlChilkat PureBasic Downloads
IncludeFile "CkHttp.pb"
IncludeFile "CkXml.pb"
IncludeFile "CkXmlDSig.pb"
IncludeFile "CkXmlDSigGen.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkCert.pb"
Procedure ChilkatExample()
success.i = 0
; This example requires the Chilkat API to have been previously unlocked.
; See Global Unlock Sample for sample code.
; This example inserts an XML signature in the following XML:
; <?xml version="1.0" encoding="UTF-8" standalone="no"?>
; <abc>
; <xyz>
; <name>helloWorld.xml</name>
; <url>https://www.chilkatsoft.com/data/helloWorld.xml</url>
; </xyz>
; </abc>
; Build the above XML to be signed.
xml.i = CkXml::ckCreate()
If xml.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkXml::setCkTag(xml, "abc")
CkXml::ckUpdateChildContent(xml,"xyz|name","helloWorld.xml")
CkXml::ckUpdateChildContent(xml,"xyz|url","https://www.chilkatsoft.com/data/helloWorld.xml")
cert.i = CkCert::ckCreate()
If cert.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkCert::ckLoadPfxFile(cert,"qa_data/pfx/test_secret.pfx","secret")
If success = 0
Debug CkCert::ckLastErrorText(cert)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
ProcedureReturn
EndIf
gen.i = CkXmlDSigGen::ckCreate()
If gen.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
; Indicate the location within the XML the Signature will be inserted.
CkXmlDSigGen::setCkSigLocation(gen, "abc|xyz")
; Get the content of the XML data to be referenced.
http.i = CkHttp::ckCreate()
If http.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
sbExternalXml.i = CkStringBuilder::ckCreate()
If sbExternalXml.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkHttp::ckQuickGetSb(http,"https://www.chilkatsoft.com/data/helloWorld.xml",sbExternalXml)
If success = 0
Debug CkHttp::ckLastErrorText(http)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
ProcedureReturn
EndIf
success = CkXmlDSigGen::ckAddExternalXmlRef(gen,"https://www.chilkatsoft.com/data/helloWorld.xml",sbExternalXml,"sha256","EXCL_C14N","")
If success = 0
Debug CkXmlDSigGen::ckLastErrorText(gen)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
ProcedureReturn
EndIf
; Provide the private key for signing via the certificate, and indicate that
; we want the base64 of the certificate embedded in the KeyInfo.
CkXmlDSigGen::setCkKeyInfoType(gen, "X509Data")
CkXmlDSigGen::setCkX509Type(gen, "Certificate")
bUsePrivateKey.i = 1
success = CkXmlDSigGen::ckSetX509Cert(gen,cert,bUsePrivateKey)
If success <> 1
Debug CkXmlDSigGen::ckLastErrorText(gen)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
ProcedureReturn
EndIf
; Indicate we want an indented signature for readability.
; This can be removed after debugging is finished..
CkXmlDSigGen::setCkBehaviors(gen, "IndentedSignature")
; Now create and insert the Signature
sbXml.i = CkStringBuilder::ckCreate()
If sbXml.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
CkXml::ckGetXmlSb(xml,sbXml)
success = CkXmlDSigGen::ckCreateXmlDSigSb(gen,sbXml)
If success <> 1
Debug CkXmlDSigGen::ckLastErrorText(gen)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
ProcedureReturn
EndIf
; Examine the XML with the digital signature inserted
Debug CkStringBuilder::ckGetAsString(sbXml)
; Here is the output:
; <?xml version="1.0" encoding="utf-8"?>
; <abc>
; <xyz>
; <name>helloWorld.xml</name>
; <url>https://www.chilkatsoft.com/data/helloWorld.xml</url>
; <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
; <ds:SignedInfo>
; <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
; <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
; <ds:Reference URI="https://www.chilkatsoft.com/data/helloWorld.xml">
; <ds:Transforms>
; <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
; </ds:Transforms>
; <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
; <ds:DigestValue>H/s775OZhel6wdBhe02l4LK6m0lkplOisKxAbVwWxp0=</ds:DigestValue>
; </ds:Reference>
; </ds:SignedInfo>
; <ds:SignatureValue>UruwnBqh..Ll4IzUA==</ds:SignatureValue>
; <ds:KeyInfo>
; <ds:X509Data>
; <ds:X509Certificate>MIIHAz...nUZWCaDE=</ds:X509Certificate>
; </ds:X509Data>
; </ds:KeyInfo>
; </ds:Signature></xyz>
; </abc>
; Let's verify the signature...
verifier.i = CkXmlDSig::ckCreate()
If verifier.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkXmlDSig::ckLoadSignatureSb(verifier,sbXml)
If success <> 1
Debug CkXmlDSig::ckLastErrorText(verifier)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
CkXmlDSig::ckDispose(verifier)
ProcedureReturn
EndIf
; Let's examine the external references, and fetch the data for each..
sbExternalData.i = CkStringBuilder::ckCreate()
If sbExternalData.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
numRefs.i = CkXmlDSig::ckNumReferences(verifier)
i.i = 0
While i < numRefs
bExternal.i = CkXmlDSig::ckIsReferenceExternal(verifier,i)
If bExternal = 1
uri.s = CkXmlDSig::ckReferenceUri(verifier,i)
; We're assuming the URI is an https:// or http:// URL...
; Let's also assume we know that the referenced data is text and we want the utf-8 byte representation.
CkStringBuilder::ckClear(sbExternalData)
success = CkHttp::ckQuickGetSb(http,uri,sbExternalData)
If success = 0
Debug CkHttp::ckLastErrorText(http)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
CkXmlDSig::ckDispose(verifier)
CkStringBuilder::ckDispose(sbExternalData)
ProcedureReturn
EndIf
; Because the referenced external data was explicitly XML, it was the canonicalized XML that was digested.
; We need to canonicalize the XML in the same way as when signed.
canonXml.s = CkXmlDSig::ckCanonicalizeXml(verifier,CkStringBuilder::ckGetAsString(sbExternalData),"EXCL_C14N",0)
CkStringBuilder::ckSetString(sbExternalData,canonXml)
success = CkXmlDSig::ckSetRefDataSb(verifier,i,sbExternalData,"utf-8")
If success = 0
Debug CkXmlDSig::ckLastErrorText(verifier)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
CkXmlDSig::ckDispose(verifier)
CkStringBuilder::ckDispose(sbExternalData)
ProcedureReturn
EndIf
EndIf
i = i + 1
Wend
; Now that we have the external data available, we can verify the reference digest(s) and the signature.
bVerified.i = CkXmlDSig::ckVerifySignature(verifier,1)
If bVerified <> 1
Debug CkXmlDSig::ckLastErrorText(verifier)
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
CkXmlDSig::ckDispose(verifier)
CkStringBuilder::ckDispose(sbExternalData)
ProcedureReturn
EndIf
Debug "Signature verified!"
CkXml::ckDispose(xml)
CkCert::ckDispose(cert)
CkXmlDSigGen::ckDispose(gen)
CkHttp::ckDispose(http)
CkStringBuilder::ckDispose(sbExternalXml)
CkStringBuilder::ckDispose(sbXml)
CkXmlDSig::ckDispose(verifier)
CkStringBuilder::ckDispose(sbExternalData)
ProcedureReturn
EndProcedure