How to tell if a file has been changedCompare it with a trusted copy, or with a fingerprint recorded earlier

Steps: check whether a file changed

1. Get the trusted copy. This is the original, the version you were first sent, or a copy you made earlier. Do not open and re-save either file.
2. Compare them. Drop both in the file comparison checker.
3. Read the result. A match means identical contents. No match means the files differ. It does not say who changed one or when.
4. See what changed. The fingerprint cannot show where. Use your program’s compare feature, such as Word’s Compare or the PDF reader’s compare tool, or a text diff.
5. Record the fingerprint next time. A TimeBind records the fingerprint with a time, so you can check a file against it years later.

What if there is no earlier fingerprint?

Then a fingerprint of the file you hold now cannot answer the question on its own. You can still compare against other copies: an email attachment as sent, a version held by the other party, or a backup. If those match the file you hold, that is useful. If they disagree, keep every copy unaltered and ask a qualified professional before you change or discard anything. For files you will need later, record the fingerprint at the moment the file matters. See also how to protect yourself from AI forgeries.

What a TimeBind shows, and what it does not

• It shows that this exact file existed no later than the recorded time, and that a copy shown later still matches its fingerprint.
• It does not show who made the file, who owns it, that its contents are true, or whether AI was used to make or edit it.
• It does not replace legal advice, a notary where one is required, or a court’s own view of the evidence.