Xbase++

Verify an XML Signature with Multiple References

See more XML Digital Signatures Examples

Demonstrates how to verify an XML digital signature that contains multiple references. Xbase++

LOCAL nSuccess
LOCAL oHttp
LOCAL oSbXml
LOCAL oVerifier
LOCAL nVerifyReferenceDigests
LOCAL nVerified
LOCAL nSignedInfoVerified
LOCAL nNumRefs
LOCAL i
LOCAL nRefDigestVerified

nSuccess := 0

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

//  An example of an enveloping XML signature with mulitple references is available at
//  https://www.chilkatsoft.com/exampleData/envelopedMultipleRefs.xml

//  This example will show how to verify the signature and all references, and also how
//  to verify each reference individually.  This is useful to distinguish which part
//  of the XML signature validation failed.  It could be that one or more of the references
//  failed because of a hash computation mismatch.  Or it could be that the signature over
//  the SignedInfo failed.  

//  First, let's grab the sample XML signature.
oHttp := CreateObject("Chilkat.Http")
oSbXml := CreateObject("Chilkat.StringBuilder")
nSuccess := oHttp:QuickGetSb("https://www.chilkatsoft.com/exampleData/envelopedMultipleRefs.xml", oSbXml)
IF (nSuccess != 1)
    ? oHttp:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    RETURN
ENDIF

//  Load the XML containing the signature to be verified.
oVerifier := CreateObject("Chilkat.XmlDSig")
nSuccess := oVerifier:LoadSignatureSb(oSbXml)
IF (nSuccess != 1)
    ? oVerifier:LastErrorText
    oHttp:destroy()
    oSbXml:destroy()
    oVerifier:destroy()
    RETURN
ENDIF

nVerifyReferenceDigests := 1

//  The quick way to validate all references and the signature over the SignedInfo
//  is to call VerifySignature with verifyReferenceDigests equal to 1.
nVerified := oVerifier:VerifySignature(nVerifyReferenceDigests)
? "Signature and all reference digests verified = " + Str(nVerified)

//  Let's pretend the call to VerifySignature returned 0.  Something did not validate.
//  Was it one or more of the References that did not hash to the correct value?
//  Or was it the signature over the SignedInfo that failed?
//  We can check just the signature over the SignedInfo by passing 0 to VerifySignature.
//  This allows us to skip the hashing and checking each Reference.  
nVerifyReferenceDigests := 0
nSignedInfoVerified := oVerifier:VerifySignature(nVerifyReferenceDigests)
? "Neglecting the reference hashes, the SignedInfo validation result = " + Str(nSignedInfoVerified)

//  We can also verify each reference digest separately
nNumRefs := oVerifier:NumReferences
i := 0
DO WHILE i < nNumRefs
    nRefDigestVerified := oVerifier:VerifyReferenceDigest(i)
    ? "Reference " + Str(i) + " digest verified = " + Str(nRefDigestVerified)
    i := i + 1
ENDDO

//  For this sample XML signature with 3 References, we get the following output:

//  Signature and all reference digests verified = True
//  Neglecting the reference hashes, the SignedInfo validation result = True
//  Reference 0 digest verified = True
//  Reference 1 digest verified = True
//  Reference 2 digest verified = True

oHttp:destroy()
oSbXml:destroy()
oVerifier:destroy()