The file never leaves your browser. The check hashes the signed byte ranges and compares them with the digest sealed inside each signature.
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History for this tool
The most recent data you entered in this tool, stored only in this browser.
Save what you type here, in this browser? Your work would go into this browser's local storage, so a refresh or a trip to another tool does not wipe it. You also get a short list of previous entries under the form, each one restorable with a click. Nothing is ever uploaded, and there is no account.
Being straight about the trade-off: anything kept there can be read by anyone who can use this browser profile, and by any script that later runs on this site. A tool page can hold a private key, a password or a signed token. Saving is convenient; it is not private.
About this tool
Read a PDF and report the signatures it contains: who signed, when, and whether the byte range each signature covers still matches the file. It walks the PDF structure directly, with no upload and no external library.Questions
- Does this prove the signer's identity?
- No. Even an Intact digest here does not verify the public-key signature or trust the certificate. Use a full verifier and independent identity checks when it matters.
- Why is a signature reported as invalid?
- A mismatch can mean the signed byte range changed, or that the format or range was not interpreted as expected. Could not verify can also mean an unsupported digest. Do not infer the cause or the signer’s identity from this lightweight result alone.