(Unicode C) Verify an XML Signature with Multiple References

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

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#include <C_CkHttpW.h>
#include <C_CkStringBuilderW.h>
#include <C_CkXmlDSigW.h>

void ChilkatSample(void)
    {
    HCkHttpW http;
    HCkStringBuilderW sbXml;
    BOOL success;
    HCkXmlDSigW verifier;
    BOOL verifyReferenceDigests;
    BOOL verified;
    BOOL signedInfoVerified;
    int numRefs;
    int i;
    BOOL refDigestVerified;

    // 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.
    http = CkHttpW_Create();
    sbXml = CkStringBuilderW_Create();
    success = CkHttpW_QuickGetSb(http,L"https://www.chilkatsoft.com/exampleData/envelopedMultipleRefs.xml",sbXml);
    if (success != TRUE) {
        wprintf(L"%s\n",CkHttpW_lastErrorText(http));
        CkHttpW_Dispose(http);
        CkStringBuilderW_Dispose(sbXml);
        return;
    }

    // Load the XML containing the signature to be verified.
    verifier = CkXmlDSigW_Create();
    success = CkXmlDSigW_LoadSignatureSb(verifier,sbXml);
    if (success != TRUE) {
        wprintf(L"%s\n",CkXmlDSigW_lastErrorText(verifier));
        CkHttpW_Dispose(http);
        CkStringBuilderW_Dispose(sbXml);
        CkXmlDSigW_Dispose(verifier);
        return;
    }

    verifyReferenceDigests = TRUE;

    // The quick way to validate all references and the signature over the SignedInfo
    // is to call VerifySignature with verifyReferenceDigests equal to TRUE.
    verified = CkXmlDSigW_VerifySignature(verifier,verifyReferenceDigests);
    wprintf(L"Signature and all reference digests verified = %d\n",verified);

    // Let's pretend the call to VerifySignature returned FALSE.  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 FALSE to VerifySignature.
    // This allows us to skip the hashing and checking each Reference.  
    verifyReferenceDigests = FALSE;
    signedInfoVerified = CkXmlDSigW_VerifySignature(verifier,verifyReferenceDigests);
    wprintf(L"Neglecting the reference hashes, the SignedInfo validation result = %d\n",signedInfoVerified);

    // We can also verify each reference digest separately
    numRefs = CkXmlDSigW_getNumReferences(verifier);
    i = 0;
    while (i < numRefs) {
        refDigestVerified = CkXmlDSigW_VerifyReferenceDigest(verifier,i);
        wprintf(L"Reference %d digest verified = %d\n",i,refDigestVerified);
        i = i + 1;
    }

    // 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 = Tru


    CkHttpW_Dispose(http);
    CkStringBuilderW_Dispose(sbXml);
    CkXmlDSigW_Dispose(verifier);

    }