Screen Any Audio File, Get a Public Signed Audit Log — Selekt Workshop, Explained
Anyone can run a copyright check. What no one else gives you is a tamper-proof, publicly re-verifiable record that the check ran. Selekt Workshop screens any audio you upload against ACR Cloud, signs the result with Ed25519, and gives you a public URL anyone can verify in their browser. Here is when that matters, how it works, and what it is not.
The gap nobody else fills
Anyone can run a copyright check. ACR Cloud is an API. You can sign up, hit the endpoint, and get back a JSON response telling you whether your audio matched anything in the world’s commercial-music catalog. That part of the workflow has been a commodity for years.
What is missing — and what producers, composers, podcasters, and developers consistently get burned by — is the receipt. The raw ACR response sits in your terminal. A screenshot of someone’s portal is the audio-clearance equivalent of “trust me.” You can’t hand a JSON dump to a label and expect them to verify it themselves. You can’t put a screenshot in a sync submission and expect a music supervisor to weight it as evidence.
What every workflow actually needs is a third-party-signed, time-stamped, publicly re-verifiable record that the check ran. That record is the artifact distributors, sync supervisors, podcast platforms, app-store reviewers, and rights-holder teams actually want to see. The verdict is half the value; the receipt is the other half.
What Selekt’s Workshop does
Upload any audio file to the Audio Workshop tool. Selekt sends it to ACR Cloud — the same fingerprint database that powers Shazam, Deezer, and Musixmatch — and gets back the full per-segment match result. So far, indistinguishable from running ACR yourself.
Then Selekt does what ACR doesn’t: signs the result.
The full ACR response, the timestamp, the source SHA-256, the per-segment offsets, the disclaimer text shown to you at scan time — all of it is canonicalized into a single record and signed with an Ed25519 private key Selekt holds. The signature is added to an append-only chain. The record is published at a stable public URL: <code>selektaudio.com/verify/scan/<scanId></code>.
That URL is the product. You can hand it to anyone. They can open it in any browser. They click “Verify Signature.” The cryptographic check runs entirely in their browser, against Selekt’s openly-published public key, with no round-trip to Selekt during the verification. Either the signature matches the record byte-for-byte, or it doesn’t. There is no middle ground, no place for Selekt to fudge, no opportunity for either side to alter the result after the fact.
Who actually needs this
Producers handing tracks to a label or sync supervisor. The supervisor needs to confirm the producer ran due diligence. A signed scan URL beats “I ran a check, I promise” — they can verify the timestamp, the source file SHA-256, and the verdict themselves in 10 seconds.
Composers scoring film, TV, advertising, library catalogs, trailers, or games. Cue sheets often include sourcing documentation. A signed scan URL alongside the cue sheet is documentation the agency can re-verify rather than take on faith.
Podcasters facing the wave of NMPA takedown actions on podcast platforms. The NMPA launched targeted takedowns against Spotify podcasts using unlicensed music in 2025; similar actions roll through other podcast hosts. A signed pre-publish scan for every episode is exactly the artifact a takedown response needs.
Game developers and app developers attaching asset-clearance evidence to store submissions or platform partner reviews. The reviewer doesn’t want a screenshot — they want something they can verify independently, ideally in their own browser, ideally without contacting you. A signed scan URL is exactly that.
Library and production music composers submitting to sync agencies. Libraries reject submissions when they can’t verify the underlying ownership claim. A signed scan that ran before submission turns the library’s default-rejection into a default-acceptance.
Anyone in a copyright dispute or DMCA pushback. A pre-existing signed scan from before the dispute began is primary evidence — Selekt cannot have generated it after the fact without breaking the signature.
How it’s different from running ACR Cloud yourself
You could subscribe to ACR Cloud’s API. You could screen every track you make. You could keep the JSON responses in a folder. None of that is wrong. It just isn’t portable evidence.
When you do it yourself, the responses live in your filesystem. To prove to a third party that any specific scan happened, you have to either trust the third party with raw ACR API access (they probably don’t want that responsibility) or hand them a file you produced yourself (which they have no way to verify wasn’t edited).
When Selekt does it, the response lives behind a signed, publicly-fetchable URL. The signature is a cryptographic commitment Selekt made at a specific moment, against specific bytes, that anyone can re-check. The math is the same Ed25519 that secures HTTPS in your browser’s address bar. Selekt cannot retroactively alter the result; the worst Selekt could do is append a contradicting record to the chain, which would itself be a signed and timestamped admission.
The structural difference is who’s vouching for what. When you screen yourself, you’re asking the world to trust you that you screened. When Selekt screens, the world only has to trust the math — and the math is verifiable by anyone with a browser.
How the workflow looks
Open the Audio Workshop. Upload the file you want screened. The interface walks you through a brief pre-scan disclaimer (so the audit record captures that you saw it and agreed). Selekt chunks the file, sends each chunk to ACR Cloud, collects the per-segment results, and signs the whole thing.
When the scan finishes, you see the verdict (clear, match, or — rarely — error), the per-segment breakdown of what matched if anything, and the share URL. The full result also lives in your Library under the Copyright Checks tab, where you can pull it up again later and share the URL.
When you hand the URL to anyone — a label, an agency, a platform reviewer — they open it, see the same substance you saw (verdict, per-segment matches, source SHA-256, timestamp, signing key), and can click the verify button to run the Ed25519 check themselves. If the signature is intact, they trust the record. If something has been altered, the check fails and they know to ask questions.
What it is not — the honest framing
A Selekt scan is not a legal clearance opinion. A signed receipt that ACR returned “clear” means the database had no match at scan time. It does not mean the audio is free of all copyrighted material. ACR Cloud is excellent — it catches the vast majority of commercially-released recordings — but no fingerprint database is exhaustive.
A Selekt scan is also not a determination about underlying composition rights. Two recordings of the same composition won’t fingerprint-match each other. ACR is a recording-level fingerprint, not a composition-level analyzer. If you covered a song without clearing the publishing, ACR returning “clear” on your version doesn’t change that.
And a Selekt scan is not a claim about the underlying audio’s ownership. Selekt did not create, source, or distribute whatever you uploaded; only the screening process and the signed record. The receipt documents what happened during the scan — not who owns what.
What the receipt does is exactly what it says: prove that the scan ran at the time shown, against the file with the SHA-256 shown, and produced the verdict shown. That is what reviewers actually want to see. Everything else is downstream of having that artifact.
Try it on something you actually need screened
The Audio Workshop tool is at <a href="/workshop">selektaudio.com/workshop</a>. Upload an audio file — your own production, a sample you sourced, a podcast bed, anything you want a signed receipt for. The scan takes a couple of minutes for typical-length material; you’ll get the verdict and the public URL when it’s done.
A real example of the result page is at <a href="/verify/scan/scan_394de07f11e442d0">selektaudio.com/verify/scan/scan_394de07f11e442d0</a> — that’s a scan that returned a match, showing exactly what the per-segment detail looks like when ACR finds something. The verification button is at the top of the page. The detail breakdown is below it. The raw signed JSON is at the bottom for the technically-minded.
Run a scan once. Hand the URL to whoever you would normally have to email a screenshot to. The conversation changes.
Frequently Asked Questions
How is this different from just running ACR Cloud’s API myself?
The raw ACR result is a private query in your terminal — useful to you, unverifiable to anyone else. Selekt signs the result with Ed25519, publishes it at a public URL, and lets anyone re-verify it in their browser without contacting you. The verdict is the same; the difference is that the result becomes evidence anyone can check.
Does a “clear” verdict mean my audio is legally cleared?
No, and we are careful not to claim that. It means ACR Cloud had no match at scan time. ACR catches the vast majority of commercially-released recordings but no fingerprint database is exhaustive, and ACR is recording-level (it does not analyze underlying composition rights). The receipt documents that the screen ran — not that the audio is free of all copyright concerns.
Who actually accepts this as evidence?
Music supervisors, sync agencies, distributors, podcast platforms, app-store reviewers, and rights-holder dispute teams. Anyone who needs to confirm a scan happened and verify the result independently. The signed audit chain pattern is the same cryptography (Ed25519) used by HTTPS, GitHub commit signing, and Tor — boring, mature, widely trusted.
What if Selekt’s signing key gets compromised?
We rotate to a new key and publish the new public key openly. Records signed under the old key still verify against the published archived public key, so historical evidence stays intact; any record signed after the rotation must validate against the new key.
Can I run this on audio I didn’t upload through Selekt?
No — Workshop scans are tied to files you upload. If you want to share the verifiable URL for a file you already have, run it through Workshop and share the URL the scan produces. The signed receipt is for files Selekt screened, not for arbitrary recordings.
What does the public URL contain?
The scan ID, source file SHA-256 (so anyone can verify the file you uploaded hasn’t changed), scanned-at timestamp, per-segment results from ACR Cloud (including match titles, artists, labels, ISRCs, and confidence scores for any matches found), the signing key ID, the Ed25519 signature, and the hash linking this record to the previous record in the chain. No personal information — your name and email stay in the private companion record, never in the public one.
How long does the URL stay live?
Indefinitely. Audit records are written to permanent storage. The URL works as long as Selekt exists; if Selekt ever shuts down, the public key + the JSON records are publishable as a static archive so the verification math still works without us.
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