Why does Adobe say “signature validity is unknown”?
Adobe cannot trace the signing certificate to one it trusts. It is about the certificate, not about whether the file changed.
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Guides to signing, keeping and renewing documents
Short answers to the questions people ask about documents: signing, checking, keeping and renewing. Each one names its sources and the date we last checked them.
KuduDoc writes each guide and re-checks it against the sources it names. Here is who writes these guides.
Signing
What the law says about signing electronically, and which documents stay in ink.
Checking a document
What a signed PDF can tell you, how to tell whether one was changed, and who can confirm a document is real.
How do you check if a PDF has been edited?
Compare the file with a record made when it was finished. A PDF’s own dates can be rewritten.
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How to tell if a document is fake
Ask the organisation that issued it. Pick your document and see who can confirm it, with the official link.
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Keeping records and dates
How long to keep records, and when common documents expire.
Home and family
Lease notice dates, the move-in inspection, and what a household keeps.
Life file checklist for households
What a household keeps, where each paper original lives, what goes in the Library or the Vault, and who can reach your ordinary documents in an emergency.
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Personal is free
Keep the documents these guides are about.
Each one with its dates, its signing record and a seal anyone can check.