SmartCheck
If verification says it does not match
It is almost never fraud. The four real causes, by frequency.
It says "does not match" and the first instinct is to think someone tampered with the document. It is almost never that. These are the four real causes, and fraud is the least frequent.
| Cause | How to spot it | What to do |
|---|---|---|
| The file was reprinted or re-saved | It looks the same, weighs differently | Ask the sender for the original |
| It was converted to another format | The extension changed | Ask for the original in its format |
| It came from a much-forwarded email | Usually with a changed filename | Request it from source |
| It is a different document | Here it is worth asking | Check with whoever issued it |
Important
The first three are things anyone does without ill intent: opening a PDF and saving it from another program modifies it even if the content looks identical. Before raising a suspicion, ask for the original file — it resolves ninety per cent of cases.
How to ask for the original without accusing
"The file is not verifying for me — it has probably been re-saved along the way. Could you send me the original exactly as it reached you?" achieves the same as a suspicion and breaks nothing if, as is likely, there was nothing to suspect.
When to be concerned
Watch out
If all three coincide, do not treat it as a technical problem. A document that fails verification, says something different and arrives urgently through an odd channel is the pattern of an impersonation: phone the number you already had before acting on it.
Worth knowing
"Not found" is different from "does not match". Not found means that document was never sealed here: it may be from another issuer, or simply not certified.
›Can I find out what changed?
No. The fingerprint says it changed, not what.
›What if the original does not verify either?
Then yes, check with whoever issued it.
›Does a scanned printout verify?
No. It is a new file, even if the content is identical.
A real case
The situation
A client reports that a certificate you sent does not verify.
What you do
- Asks for the file exactly as they received it
- Finds they had re-saved it from their email client
What you get
Resolved in five minutes without anyone raising a suspicion that was never warranted.
The situation
The file was opened and re-saved.
What you do
- Checks against the untouched original copy
What you get
Verification comes out correct.
The situation
A file converted to another format is checked.
What you do
- Verifies the file exactly as sealed
What you get
The conversion stops looking like tampering.
The situation
It is compared against a different version of the document.
What you do
- Confirms which version was sealed
What you get
Like is compared with like.
The situation
The file arrived through a channel that recompresses it.
What you do
- Requests it again uncompressed
What you get
The fingerprint matches again.
The situation
It genuinely does not match and there is no explanation.
What you do
- Documents the check and escalates
What you get
The case is handled with the trail in view.
This article answers
- verification says it does not match
- the document will not verify
- error verifying a document
- the hash does not match what does it mean