Blind vs. verify mode: what is the difference?
In blind mode you supply the key but no expected ID; the detector recovers whatever CRC-valid codeword it finds. In verify mode you also supply the expected ID, so it can confirm the match and compute BER against that codeword. Blind mode is for intake; verify mode is for a known distribution record.
How Aureal handles it
Both modes search the same bands and preamble and require a CRC-valid codeword. Blind mode reports the recovered ID and a BER of 0 by construction; verify mode additionally checks the ID, reports a real BER and can reject a CRC-valid but wrong codeword. The leak-audit script uses blind detection because it does not know which recipient to expect, then looks the recovered ID up in the manifest. If you already know the ID, verify mode is the tighter check. Neither mode works with the wrong key: a mismatched key produces noise rather than an authentication failure.
Common failure mode
“Blind mode is weaker because it has no expected ID, and its BER of 0 means a perfect match.”
Why it fails: Blind mode is not weaker at finding a signal; it simply has no reference ID to compare against. The BER of 0 is a definitional artifact, not evidence of quality. Use confidence, CRC and z in blind mode, and use verify mode when you have the expected ID.
Verified example
Blind intake on an unknown file:
node aureal-watermark.cjs detect leaked.mp3
# then look up recoveredPayloadId in recipients.json
Verify a known copy:
node aureal-watermark.cjs detect copy.wav --id 883921 --key "$AUREAL_KEY"
Record the mode and key with the result; a blind result and a verify result answer different questions.Example only. Validate against your own audio, codec and processing chain.
Scope and limits
- Both modes need the same key used for embedding.
- Blind-mode BER is always 0 and carries no quality signal.
- Verify mode needs the correct expected ID.
- A CRC-valid ID does not establish authorship or ownership.
Frequently asked questions
Which mode should I use for a leak?
Start blind: you usually do not know which recipient's ID is present. Recover the ID, then look it up in the private manifest. Use verify mode when you have a candidate copy and want to confirm a specific ID.
Can blind mode find any Aureal ID?
It can recover a CRC-valid ID embedded with the same key. It cannot see IDs embedded under a different key, and it cannot tell you who owns the file.
Related topics
Test the actual delivery chain. A fixture result is a starting point, not a guarantee for your material.
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