SQL Server

PDF Sign Under Existing Signature

See more PDF Signatures Examples

This example explains how sign a previously-signed PDF and place the signature appearance below the existing signature.

Note: This example requires Chilkat v9.5.0.85 or greater.

SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

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

    DECLARE @pdf int
    EXEC @hr = sp_OACreate 'Chilkat.Pdf', @pdf OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Load a PDF to be signed.
    EXEC sp_OAMethod @pdf, 'LoadFile', @success OUT, 'qa_data/pdf/sign_testing_4/hello_signed.pdf'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pdf, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pdf
        RETURN
      END

    -- The PDF we'll be signing already has a signature added in Adobe Acrobat DC.
    -- It looks like this:
    -- (Notice the Adobe background logo, which is commonly what you'll see when a signature
    -- is created by Adobe Acrobat.  Chilkat (obviously) does not create signatures using the Adobe
    -- logo because it would be a copyright violation.)

    -- (image:https://example-code.com/images/signed_once_with_adobe_acrobat.jpg/endImage)

    -- Options for signing are specified in JSON.
    DECLARE @json int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json OUT

    -- In most cases, the signingCertificateV2 and signingTime attributes are required.
    EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'signingCertificateV2', 1
    EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'signingTime', 1

    -- To put our new signature underneath the existing signature, we have to specify the page
    -- where the existing signature is found, and then we can specify "under" for the "appearance.y"
    EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'page', 1
    EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'appearance.y', 'under'

    EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'appearance.fontScale', '10.0'

    EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'appearance.text[0]', 'Reason: Agreement Accepted by John'
    EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'appearance.text[1]', 'Date: current_dt'

    -- Load the signing certificate. (Use your own certificate.)
    DECLARE @cert int
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT

    EXEC sp_OAMethod @cert, 'LoadPfxFile', @success OUT, 'qa_data/pfx/myPdfSigningCert.pfx', 'secret'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pdf
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    -- Tell the pdf object to use the certificate for signing.
    EXEC sp_OAMethod @pdf, 'SetSigningCert', @success OUT, @cert
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pdf, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pdf
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    -- Note: When adding an additional signature to a PDF, the existing signatures
    -- are validated, and this includes validating the certificates previously used to 
    -- create the existing signatures.  (A signature typically embeds the signing certs.)
    -- In some cases, the certificates and/or certs in the chain of authentication for 
    -- existing signatures are not present, and are not available on the current system.
    -- In this case, you can skip the validation by setting this keyword in UncommonOptions:
    EXEC sp_OASetProperty @pdf, 'UncommonOptions', 'NO_VERIFY_CERT_SIGNATURES'

    EXEC sp_OAMethod @pdf, 'SignPdf', @success OUT, @json, 'qa_output/hello_signed.pdf'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pdf, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pdf
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END


    PRINT 'The PDF has been successfully cryptographically signed.'

    -- Here's a screenshot of the 2nd signature positioned under the 1st in Adobe Acrobat:

    -- (image:https://example-code.com/images/signed_under_existing_signature.jpg/endImage)

    EXEC @hr = sp_OADestroy @pdf
    EXEC @hr = sp_OADestroy @json
    EXEC @hr = sp_OADestroy @cert


END
GO