DataFlex

Sign PDF in the Cloud using AWS KMS

See more Signing in the Cloud Examples

Demonstrates how to sign a PDF using the AWS Key Management Service. The signing of the hash happens in the Cloud on AWS KMS. 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.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoPdf
    Variant vJson
    Handle hoJson
    Variant vCert
    Handle hoCert
    Variant vJsonAwsKms
    Handle hoJsonAwsKms
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatPdf)) To hoPdf
    If (Not(IsComObjectCreated(hoPdf))) Begin
        Send CreateComObject of hoPdf
    End

    // Load a PDF to be signed.
    Get ComLoadFile Of hoPdf "qa_data/pdf/helloWorld.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Options for signing are specified in JSON.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End

    // Optionally create an LTV-enabled signature
    Get ComUpdateBool Of hoJson "ltvOcsp" True To iSuccess

    // Define the appearance of the signature.
    Get ComUpdateInt Of hoJson "page" 1 To iSuccess
    Get ComUpdateString Of hoJson "appearance.y" "top" To iSuccess
    Get ComUpdateString Of hoJson "appearance.x" "left" To iSuccess
    Get ComUpdateString Of hoJson "appearance.fontScale" "10.0" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[0]" "Digitally signed by: cert_cn" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[1]" "current_dt" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[2]" "This is an LTV-enabled signature." To iSuccess

    // Load the certificate used for signing.  The certificate's private key is stored in AWS KMS
    // However, we still need the certificate locally (without private key).
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get ComLoadFromFile Of hoCert "qa_data/certs/myCert.cer" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Here's a screenshot of our private key AWS KMS:
    // (image:https://example-code.com/images/aws_kms.jpg/endImage)

    // To sign using AWS KMS, 
    // add the following lines of code to specify your AWS authentication credentials,
    // and the ID of the KMS private key.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonAwsKms
    If (Not(IsComObjectCreated(hoJsonAwsKms))) Begin
        Send CreateComObject of hoJsonAwsKms
    End
    // Set the "service" equal to "aws_kms" to tell Chilkat to use AWS KMS for signing.
    Get ComUpdateString Of hoJsonAwsKms "service" "aws_kms" To iSuccess
    Get ComUpdateString Of hoJsonAwsKms "access_key" "ACCESS_KEY" To iSuccess
    Get ComUpdateString Of hoJsonAwsKms "secret_key" "SECRET_KEY" To iSuccess
    // Make sure to specify the correct region for your case.
    Get ComUpdateString Of hoJsonAwsKms "region" "us-west-2" To iSuccess
    // In the above screenshot, our key ID is "187012e8-008f-4fc7-b100-5efe6146dff2".  You will use your key ID.
    Get ComUpdateString Of hoJsonAwsKms "key_id" "187012e8-008f-4fc7-b100-5efe6146dff2" To iSuccess

    Get pvComObject of hoJsonAwsKms to vJsonAwsKms
    Get ComSetCloudSigner Of hoCert vJsonAwsKms To iSuccess

    // Tell the pdf object to use the certificate for signing (and for AWS KMS to do the actual signing of the hash).
    Get pvComObject of hoCert to vCert
    Get ComSetSigningCert Of hoPdf vCert To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Chilkat will build the signed PDF locally, but will (internally) use AWS KMS
    // to do the RSA (or EC) sign hash operation.
    Get pvComObject of hoJson to vJson
    Get ComSignPdf Of hoPdf vJson "qa_output/hello_ltv_signed.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "PDF Cloud Signing using AWS KMS Successful."


End_Procedure