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List the digital signatures attached to a PDF document

Source: R/signatures.R
pdf_signatures.Rd

Returns a tibble row per signature object in the document. Wraps FPDF_GetSignatureCount, FPDF_GetSignatureObject, and the FPDFSignatureObj_* scalar accessors.

Usage

pdf_signatures(doc)

Arguments

doc

A pdfium_doc from pdf_doc_open(), or a character path.

Value

A tibble with columns:

  • signature_index integer - 1-based; pass to pdf_signature_contents() / pdf_signature_byte_range().

  • sub_filter character - the signature's /SubFilter value, e.g. "adbe.pkcs7.detached", "ETSI.CAdES.detached", "adbe.x509.rsa_sha1". ASCII.

  • reason character - UTF-8 reason / comment string, attached when the signer wrote one. Empty if absent.

  • time character - signing time in PDF date format ("D:YYYYMMDDHHmmSS+HH'mm'"). Empty if the signature defers to the timestamp inside the PKCS#7 blob. Pass to pdf_parse_date() for a POSIXct.

  • doc_mdp_permission integer - 1, 2, or 3 (PDF DocMDP permission level: no changes / form-fill only / form-fill

    • annotations + signing fields). NA when no DocMDP entry is present.

  • contents_size integer - byte length of the signature blob (DER-encoded PKCS#1 or PKCS#7).

  • byte_range_pairs integer - number of (offset, length) pairs covered by the signed digest. Pass signature_index to pdf_signature_byte_range() for the actual pairs.

Returns a 0-row tibble of the same schema when the document has no signatures.

See also

pdf_signature_contents() for the raw PKCS#7 / PKCS#1 bytes, pdf_signature_byte_range() for the signed byte ranges, pdf_parse_date() for parsing the time column.