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(PureBasic) PDF Sign Unsigned Signature Field
Demonstrates how to sign a PDF's unsigned signature field.
Note: This example requires Chilkat v9.5.0.85 or greater.
IncludeFile "CkCert.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkPdf.pb"
Procedure ChilkatExample()
; This example requires the Chilkat API to have been previously unlocked.
; See Global Unlock Sample for sample code.
pdf.i = CkPdf::ckCreate()
If pdf.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
; Load a PDF containing an unsigned signature field.
success.i = CkPdf::ckLoadFile(pdf,"qa_data/pdf/unsigned_sig_field/due_diligence.pdf")
If success = 0
Debug CkPdf::ckLastErrorText(pdf)
CkPdf::ckDispose(pdf)
ProcedureReturn
EndIf
; A PDF with an unsigned signature field appears in Adobe Acrobat as shown below.
; (When the mouse pointer is hovered over the field, a tooltip will likely show a message
; such as "Unsigned signature field (Click to sign)".
; This example code will automatically find the unsigned signature field,
; and signs using your certificate. It automatically sizes the text to the space alotted
; for the signature.
; Options for signing are specified in JSON.
json.i = CkJsonObject::ckCreate()
If json.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
; In most cases, the signingCertificateV2 and signingTime attributes are required.
CkJsonObject::ckUpdateInt(json,"signingCertificateV2",1)
CkJsonObject::ckUpdateInt(json,"signingTime",1)
; We don't specify the page or a specific location because Chilkat will automatically
; find the unsigned signature field and use its location and size and will scale the
; signatures visual appearance (text + graphics) to the correct size required to fit.
; We only need to indicate the desire to fill the unsigned signature field.
CkJsonObject::ckUpdateBool(json,"appearance.fillUnsignedSignatureField",1)
; Starting in Chilkat v9.5.0.90, if a PDF contains multiple unsigned signature fields,
; the field to be signed can be chosen by name:
; To list unsigned signature fields, see this example: List PDF Unsigned Signature Fields
CkJsonObject::ckUpdateString(json,"unsignedSignatureField","doctor_signature")
; Note: If the PDF document contains multiple unsigned signature fields, Chilkat will
; sign the 1st one found.
; In this example, the appearance of the digital signature will contain three lines:
; 1) The signing certificate's common name
; 2) The current date/time
; 3) Some arbitrary text.
; The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
; The keyword "current_dt" is replaced with the current date/time.
; Any number of appearance text lines can be added.
CkJsonObject::ckUpdateString(json,"appearance.text[0]","Digitally signed by: cert_cn")
CkJsonObject::ckUpdateString(json,"appearance.text[1]","current_dt")
CkJsonObject::ckUpdateString(json,"appearance.text[2]","The crazy brown fox jumps over the lazy dog.")
; This signature will include one of the built-in SVG graphics (green-check-grey-circle).
CkJsonObject::ckUpdateString(json,"appearance.image","green-check-grey-circle")
CkJsonObject::ckUpdateString(json,"appearance.imagePlacement","left")
; Load the signing certificate. (Use your own certificate.)
cert.i = CkCert::ckCreate()
If cert.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkCert::ckLoadPfxFile(cert,"qa_data/pfx/myPdfSigningCert.pfx","secret")
If success = 0
Debug CkCert::ckLastErrorText(cert)
CkPdf::ckDispose(pdf)
CkJsonObject::ckDispose(json)
CkCert::ckDispose(cert)
ProcedureReturn
EndIf
; Tell the pdf object to use the certificate for signing.
success = CkPdf::ckSetSigningCert(pdf,cert)
If success = 0
Debug CkPdf::ckLastErrorText(pdf)
CkPdf::ckDispose(pdf)
CkJsonObject::ckDispose(json)
CkCert::ckDispose(cert)
ProcedureReturn
EndIf
success = CkPdf::ckSignPdf(pdf,json,"qa_output/due_diligence_signed.pdf")
If success = 0
Debug CkPdf::ckLastErrorText(pdf)
CkPdf::ckDispose(pdf)
CkJsonObject::ckDispose(json)
CkCert::ckDispose(cert)
ProcedureReturn
EndIf
Debug "The PDF has been successfully cryptographically signed."
; The appearance of the signature appears in Adobe Acrobat as shown below.
CkPdf::ckDispose(pdf)
CkJsonObject::ckDispose(json)
CkCert::ckDispose(cert)
ProcedureReturn
EndProcedure
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