(DataFlex) Verify Opaque Signature and Retrieve Signing Certificates

Demonstrates how to verify a PCKS7 opaque digital signature (signed data), extract the original file/data, and then extract the certificate(s) that were used to sign.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Handle hoCrypt
    Boolean iSuccess
    Variant vBinData
    Handle hoBinData
    Integer iNumCerts
    Integer i
    Variant vCert
    Handle hoCert
    Variant vCertChain
    Handle hoCertChain
    String sTemp1

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

    Get Create (RefClass(cComChilkatCrypt2)) To hoCrypt
    If (Not(IsComObjectCreated(hoCrypt))) Begin
        Send CreateComObject of hoCrypt
    End

    // Verify a PKCS7 signed-data (opaque signature) file and extract the original content to a file.
    Get ComVerifyP7M Of hoCrypt "qa_data/p7m/opaqueSig.p7" "qa_output/originalData.dat" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Alternatively, we can do it in memory...
    Get Create (RefClass(cComChilkatBinData)) To hoBinData
    If (Not(IsComObjectCreated(hoBinData))) Begin
        Send CreateComObject of hoBinData
    End
    Get ComLoadFile Of hoBinData "qa_data/p7m/opaqueSig.p7" To iSuccess
    // Your app should check for success, but we'll skip the check for brevity..

    // If verified, the signature is unwrapped and binData is replaced with the original data that was signed.
    Get pvComObject of hoBinData to vBinData
    Get ComOpaqueVerifyBd Of hoCrypt vBinData To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCrypt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // For our testing, we signed some text, so we can get it from the binData..
    Showln "Original Data:"
    Get ComGetString Of hoBinData "utf-8" To sTemp1
    Showln sTemp1

    // After any method call that verifies a signature, the crypt object will contain the certificate(s)
    // that were used for signing (assuming the X.509 certs were available in the signature, which is typically the case).

    // Get the number of signing certificates, and get each..
    Get ComNumSignerCerts Of hoCrypt To iNumCerts
    Move 0 To i
    While (i < iNumCerts)
        Get ComGetSignerCert Of hoCrypt i To vCert
        If (IsComObject(vCert)) Begin
            Get Create (RefClass(cComChilkatCert)) To hoCert
            Set pvComObject Of hoCert To vCert
        End
        Get ComSubjectDN Of hoCert To sTemp1
        Showln sTemp1
        Send Destroy of hoCert
        Move i + 1 To i
    Loop

    // We could also get the complete certificate chain of each signer cert,
    // assuming the certs in the chain of authentication to the trusted root
    // are available on the system, or provided to Chilkat by some other means
    // (such as via the XmlCertVault class, the TrustedRoots class, etc.)
    Move 0 To i
    While (i < iNumCerts)
        Get ComGetSignerCertChain Of hoCrypt i To vCertChain
        If (IsComObject(vCertChain)) Begin
            Get Create (RefClass(cComChilkatCertChain)) To hoCertChain
            Set pvComObject Of hoCertChain To vCertChain
        End
        // You can examine the various properties and methods for certChain in the online
        // reference documentation...
        Send Destroy of hoCertChain
        Move i + 1 To i
    Loop



End_Procedure