Represents the "TransformMethod" entry of the signature reference dictionary object.

It is a required entry defined as part of the PDF 1.0 specification.

It contains a string representing a PDF name object.

This item may take one of the following valid values:.

• DocMDP
• UR
• FieldMDP

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 253, page 469.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 256, page 568.

The transform method name selects the processing applied before hashing. DocMDP constrains modification level; FieldMDP covers specific fields; UR enables usage rights; Identity applies no transform.