PDFprover

PDFprover is a formal verification tool designed to reason about properties of PDF documents and their rendering. It provides a formal model of the PDF format and a proof assistant that enables users to specify invariants about a PDF file and to check that these invariants hold under transformation, rendering, and decoding. The project is intended for researchers and developers working on correctness, reliability, and security of PDFs.

The tool comprises a specification language for describing PDF objects, streams, and cross-reference structures, a deductive proof engine, and interfaces to external solvers for automation. Verification can be performed on abstract models of PDFs or directly on concrete documents, either interactively or in batch mode. PDFprover aims to support reproducible proof development through versioned scripts and libraries of reusable lemmas.

Key features include a formal, machine-checkable model of PDF primitives, support for writing and checking invariants such as cross-reference consistency and font embedding, counterexample generation when proofs fail, and tools for importing standard PDF constructs and embedding external proofs. The project also emphasizes interoperability with existing PDF tooling for hypothesis testing and traceability of proofs to rendering behavior.

PDFprover is used in academic and industrial settings to study conformance to the PDF specification, assess security properties, and explore accessibility guarantees. It remains a research tool rather than a production workflow component, reflecting the complexity of the PDF format. The project is ongoing, with active development, documentation, and examples to illustrate proof techniques.