(Go) Sign PDF in the Cloud using AWS CloudHSM

See more Signing in the Cloud Examples

Demonstrates how to sign a PDF using AWS CloudHSM. The signing of the hash happens on a hardware token in AWS CloudHSM. Everything else involving the updating the PDF to add the signature happens locally within Chilkat.

Note: This example requires Chilkat v9.5.0.96 or greater.

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    // Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

    pkcs11 := chilkat.NewPkcs11()

    // Provide the path to the AWS CloudHSM PKCS11 driver.
    // This example runs on Windows, so we'll provide the CloudHSM DLL.
    // If your code runs on Linux, the CloudHSM driver might be at /opt/cloudhsm/lib/libcloudhsm_pkcs11.so
    pkcs11.SetSharedLibPath("C:\\Program Files\\Amazon\\CloudHSM\\lib\\cloudhsm_pkcs11.dll")

    // Your PIN should be a string containing your crypto user's login and password, with a colon char delimiting.
    // See https://docs.aws.amazon.com/cloudhsm/latest/userguide/pkcs11-pin.html
    pin := "user:password"
    userType := 1

    // Establish a PKCS logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
    success := pkcs11.QuickSession(userType,pin)
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        return
    }

    cert := chilkat.NewCert()
    success = cert.LoadFromFile("qa_data/certs/myCert.cer")
    if success == false {
        fmt.Println(cert.LastErrorText())
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        return
    }

    // Tell the certificate to link with the PKCS11 session.
    // The cert's private key should be installed on the CloudHSM.
    // If there are multiple private keys on the CloudHSM, then Chilkat will automatically
    // locate and use the private key corresponding to the certificate.
    success = cert.LinkPkcs11(pkcs11)
    if success == false {
        fmt.Println(cert.LastErrorText())
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        return
    }

    // --------------------------------------------------------------------------
    // At this point, we have the cert to be used for signing.
    // Our PDF signing code is the same as for a cert obtained from any other source..

    pdf := chilkat.NewPdf()

    // Load a PDF to be signed.
    success = pdf.LoadFile("qa_data/pdf/hello.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        pdf.DisposePdf()
        return
    }

    json := chilkat.NewJsonObject()

    json.UpdateInt("page",1)
    json.UpdateString("appearance.y","top")
    json.UpdateString("appearance.x","left")
    json.UpdateString("appearance.fontScale","10.0")
    json.UpdateString("signingAlgorithm","pss")
    json.UpdateString("hashAlgorithm","sha256")

    i := 0
    json.SetI(i)
    json.UpdateString("appearance.text[i]","Digitaly signed by: Xyz Widgets, Inc.")
    i = i + 1
    json.SetI(i)
    json.UpdateString("appearance.text[i]","current_dt")
    i = i + 1
    json.SetI(i)
    json.UpdateString("appearance.text[i]","blah blah blah")

    // The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
    success = pdf.SetSigningCert(cert)

    success = pdf.SignPdf(json,"qa_output/out.pdf")
    if success == false {
        fmt.Println(pdf.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        pdf.DisposePdf()
        json.DisposeJsonObject()
        return
    }

    // --------------------------------------------------------------------------

    // Revert to an unauthenticated session by calling Logout.
    success = pkcs11.Logout()
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        success = pkcs11.CloseSession()
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        pdf.DisposePdf()
        json.DisposeJsonObject()
        return
    }

    // When finished, close the session.
    // It is important to close the session (memory leaks will occur if the session is not properly closed).
    success = pkcs11.CloseSession()
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        cert.DisposeCert()
        pdf.DisposePdf()
        json.DisposeJsonObject()
        return
    }

    fmt.Println("Success.")

    pkcs11.DisposePkcs11()
    cert.DisposeCert()
    pdf.DisposePdf()
    json.DisposeJsonObject()