RFC3161PDF，

What an RFC 3161 timestamp is

A trusted timestamp is a cryptographic token issued by a Time Stamping Authority (TSA): the TSA signs a statement binding your document's hash to its own audited clock. Anyone can later verify that the exact bytes you hold existed at that instant — no earlier, no later — without trusting you or your computer's clock.

This tool builds a standards-compliant RFC 3161 request, sends it to the TSA you choose, and embeds the returned token into the PDF as an ETSI.RFC3161 document timestamp — the same structure Acrobat's own timestamping produces.

Your document never leaves the device

The only thing sent to the TSA is a SHA-256 hash — a 32-byte one-way fingerprint of the file. The TSA cannot reconstruct, read, or learn anything about your document from it. The request is gated behind an explicit consent checkbox that names the authority and states exactly what is transmitted.

This is the one tool on OxygenPDF that makes a network call, and it makes exactly one: a hash out, a signed token back. Everything else — hashing, embedding, saving — happens locally.

What you get

A timestamped PDF with verifiable proof inside.

When to use it

Timestamp drafts and designs to establish IP priority. Timestamp contracts to defeat backdating claims. Timestamp audit exports and financial records so the log itself proves when each entry existed. Because the token is embedded in the PDF, the proof travels with the file — no separate .tsr file to keep track of.

Encrypted PDFs are supported: the file is decrypted locally first (with the password you supply), then timestamped. The output is unencrypted.