This class provides methods for interacting with digital signatures of a PDF file.
Public Class Methods
Embeds the given
signature into the /Contents value of the newest signature dictionary of the PDF document given by the
Note: This will, most probably, only work on documents prepared for external signing by
HexaPDF and not by other libraries.
Uses the information in the given cross-reference section as well as the byte offset of the cross-reference section to calculate the offset and length of the signature dictionary with the given object id.
Replaces the value of the /Contents key in the serialized
signature_data with the value of
Public Instance Methods
Adds a signature to the document and returns the corresponding signature object.
This method will add a new signature to the document and write the updated document to the given file or IO stream. Afterwards the document can't be modified anymore and still retain a correct digital signature. To modify the signed document (e.g. for adding another signature) create a new document based on the given file or IO stream instead.
Can either be a signature object (determined via the /Type key), a signature field or
nil. Providing a signature object or signature field provides for more control, e.g.:
Setting values for optional signature object fields like /Reason and /Location.
(In)directly specifying which signature field should be used.
If a signature object is provided and it is not associated with an AcroForm signature field, a new signature field is created and added to the main AcroForm object, creating that if necessary.
If a signature field is provided and it already has a signature object as field value, that signature object is discarded.
If the signature field doesn't have a widget, a non-visible one is created on the first page.
The key-value pairs of this hash will be passed on to the
HexaPDF::Document#writemethod. Note that
incrementalwill be automatically set to ensure proper behaviour.
The used signature object will have the following default values set:
The current time.
These values can be overridden in the finalize_objects method of the signature handler.
Returns the number of signatures in the PDF document. May be zero if the document has no signatures.
Iterates over all signatures in the order they are found.