Seal of Authenticity — what it is and why journalists need it
June 4, 2026 · 4 min read · Verification
When a journalist publishes a quote, the implicit promise is: "This is what was said." But what happens when a source denies it? When an editor questions the version? When the case reaches a court?
Until now, there was no technical way to prove that a transcription was not altered. Tangara's Seal of Authenticity changes that.
What is a SHA-256 hash?
A hash is a unique digital fingerprint. SHA-256 takes any file — an audio, a document, an image — and generates a 64-character string that represents it uniquely. If even one second of the audio changes, the hash changes completely.
It's the same system used to verify software downloads and sign legal documents. It's not new — but until now it wasn't accessible to journalists without technical knowledge.
How does it work in Tangara?
- You upload your audio to Tangara.
- Before processing, Tangara calculates the SHA-256 hash of the original file.
- The transcription is generated and the hash is permanently associated with the text.
- You receive a certificate with the hash, a UTC timestamp, and a QR verification link.
- The audio is deleted from the servers — only the hash remains, not the content.
When to use it
- Sensitive interviews: declarations by officials, accusations, denials.
- Investigative journalism: evidence that needs to maintain a chain of custody.
- Legal disputes: when a source claims they didn't say what the transcription says.
- Editorial processes: demonstrating to your editor that the quote is verbatim.
The downloadable certificate
Each Tangara transcription generates a certificate with a QR code that, when scanned, takes to a public verification page at tangara.rumbi.io. Anyone — a judge, an editor, a fact-checker — can verify that the text hasn't been altered since it was generated.
It doesn't require Tangara. It doesn't require an account. It's a public URL with the hash and the timestamp.