DataFlex

Verify Opaque Signature and Retrieve Signing Certificates

See more Digital Signatures Examples

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. DataFlex

Use ChilkatAx-win32.pkg

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

    Move False To iSuccess

    // 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 = False) 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 = False) 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 each signing certificate, and build the certificate chain for each.
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get Create (RefClass(cComChilkatCertChain)) To hoCertChain
    If (Not(IsComObjectCreated(hoCertChain))) Begin
        Send CreateComObject of hoCertChain
    End
    Get ComNumSignerCerts Of hoCrypt To iNumCerts
    Move 0 To i
    While (i < iNumCerts)
        Get pvComObject of hoCert to vCert
        Get ComLastSignerCert Of hoCrypt i vCert To iSuccess
        Get ComSubjectDN Of hoCert To sTemp1
        Showln sTemp1

        Get pvComObject of hoCertChain to vCertChain
        Get ComBuildCertChain Of hoCert vCertChain To iSuccess
        If (iSuccess = False) Begin
            Get ComLastErrorText Of hoCert To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        Move (i + 1) To i
    Loop



End_Procedure