verify_pdf_signature: Verify the digital signatures of a PDF

In pdfsigner: Digitally Sign and Verify PDF Documents

Verify the digital signatures of a PDF

Description

Cryptographically verifies every signature and document timestamp in pdf_file using the bundled Rust backend. Each signature is checked by re-deriving its signed byte range, validating the CMS profile (content-type, message-digest, ESS certificate binding) and the signer's signature over the signed attributes. The document is also judged as a whole: it is only intact when the last valid signature or document timestamp covers the entire file, or when everything appended after it is a PAdES ⁠/DSS⁠ (long-term validation material). Content changed after signing therefore fails document_intact even though the original signature still verifies over its own bytes.

Usage

verify_pdf_signature(pdf_file, roots = NULL)

Arguments

pdf_file	Path to the PDF to verify.
roots	Optional path to a PEM file of trusted root certificates (e.g. the ICP-Brasil AC Raiz set). When supplied, each signer certificate chain (and each timestamp authority's) is validated against these roots and reported in chain_trusted; for timestamped signatures the chain is judged at the timestamp's genTime, exposed as trusted_time.

Value

A list with one entry per signature or document timestamp, in file order. Each entry is a named list with valid (logical), is_timestamp (logical, TRUE for a ⁠/DocTimeStamp⁠), signer (subject DN), chain_trusted (logical or NA when no roots given), covers_whole_document (logical), trusted_time (seconds since the Unix epoch of the trusted timestamp used, or NA), signed_len (bytes), byte_range (numeric length-4) and detail. The list carries three logical attributes with the document-level verdict: document_intact, all_valid (every entry valid and the document intact) and all_trusted (all_valid and every entry chains to one of roots; always FALSE without roots). A length-zero list means no signatures were found.

Examples

## Not run: 
result <- verify_pdf_signature("signed.pdf", roots = "icp-brasil-roots.pem")
vapply(result, function(s) s$valid, logical(1))
attr(result, "all_trusted")   # the one-line verdict

## End(Not run)

pdfsigner documentation built on Sept. 25, 2026, 5:09 p.m.