(PureBasic) SAML Signature Validation

See more XML Digital Signatures Examples

A SAML Signature is an XML Digital Signature (XMLDSig) just like any other XML digital signature. It can be verified by using Chilkat' XmlDSig class, as shown in this example.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkXmlDSig.pb"

Procedure ChilkatExample()

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

    dsig.i = CkXmlDSig::ckCreate()
    If dsig.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkXmlDSig::ckLoadSignature(dsig,"XML xml signature goes here...")

    ; A sample SAML signature is shown below..

    numSignatures.i = CkXmlDSig::ckNumSignatures(dsig)
    i.i = 0
    While i < numSignatures
        CkXmlDSig::setCkSelector(dsig, i)

        bVerifyRefDigests.i = 0
        bSignatureVerified.i = CkXmlDSig::ckVerifySignature(dsig,bVerifyRefDigests)
        If bSignatureVerified = 1
            Debug "Signature " + Str(i + 1) + " verified"
        Else
            Debug "Signature " + Str(i + 1) + " invalid"
        EndIf

        ; Check each of the reference digests separately..
        numRefDigests.i = CkXmlDSig::ckNumReferences(dsig)
        j.i = 0
        While j < numRefDigests
            bDigestVerified.i = CkXmlDSig::ckVerifyReferenceDigest(dsig,j)
            Debug "reference digest " + Str(j + 1) + " verified = " + Str(bDigestVerified)
            If bDigestVerified = 0
                Debug "    reference digest fail reason: " + Str(CkXmlDSig::ckRefFailReason(dsig))
            EndIf

            j = j + 1
        Wend

        i = i + 1
    Wend

    ; --------------------------------------
    ; Here is a sample SAML XML Signature
    ; 
    ; 
    ; <?xml version="1.0" encoding="UTF-8"?>
    ; <saml2p:Response xmlns:saml2p="urn:oasis:names:tc:SAML:2.0:protocol" ID="abc123" Version="2.0" IssueInstant="2022-04-01T12:34:56Z" Destination="https://sp.example.com/sso">
    ;   <saml2:Issuer xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">https://idp.example.com</saml2:Issuer>
    ;   <saml2p:Status>
    ;     <saml2p:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/>
    ;   </saml2p:Status>
    ;   <saml2:Assertion xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" ID="def456" IssueInstant="2022-04-01T12:34:56Z" Version="2.0">
    ;     <saml2:Issuer>https://idp.example.com</saml2:Issuer>
    ;     <saml2:Subject>
    ;       <saml2:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">user@example.com</saml2:NameID>
    ;     </saml2:Subject>
    ;     <saml2:Conditions NotBefore="2022-04-01T12:34:56Z" NotOnOrAfter="2022-04-01T13:34:56Z"/>
    ;     <saml2:AuthnStatement AuthnInstant="2022-04-01T12:34:56Z">
    ;       <saml2:AuthnContext>
    ;         <saml2:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:Password</saml2:AuthnContextClassRef>
    ;       </saml2:AuthnContext>
    ;     </saml2:AuthnStatement>
    ;     <!-- Additional assertion content -->
    ;   </saml2:Assertion>
    ;   <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="#abc123">
    ;         <ds:Transforms>
    ;           <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
    ;           <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>q7Zj1w+...+pCsjw=</ds:DigestValue>
    ;       </ds:Reference>
    ;       <!-- Additional references if present -->
    ;     </ds:SignedInfo>
    ;     <ds:SignatureValue>
    ;       NjIzOWE5ZjA2M2M1...NzUwNzUwNzUwNzUwNzU=
    ;     </ds:SignatureValue>
    ;     <ds:KeyInfo>
    ;       <ds:X509Data>
    ;         <ds:X509Certificate>
    ;           MIIDgzCCAmugAwIBAg...AgADAA==
    ;         </ds:X509Certificate>
    ;       </ds:X509Data>
    ;     </ds:KeyInfo>
    ;   </ds:Signature>
    ; </saml2p:Response>


    CkXmlDSig::ckDispose(dsig)


    ProcedureReturn
EndProcedure