[casmolin]

Adds a soft binding entry for AIDR Studio's deployment of the SilentCipher audio watermark.

Submitter: Casper Molin, AIDR Studio (Postavermaas, the Netherlands), the company that operates this deployment and its manifest repository.

Algorithm

• Sony Research's open SilentCipher model (44.1 kHz model, silentcipher 1.0.5, MIT; paper: SilentCipher: Deep Audio Watermarking, Interspeech 2024), deployed without retraining.
• Embeds a 40-bit payload into every AI-generated speech clip before the C2PA manifest is signed: the public AIDR brand byte 0xAD followed by a 32-bit per-clip identifier, drawn from a cryptographic random source and reserved in AIDR's watermark register. The identifier contains no personal data.
• Supports both embedding and extraction. The identifier resolves to the clip's original C2PA manifest in AIDR's register, so provenance can be recovered after sample-rate conversion, re-encoding or metadata stripping (digital audio workstations add RIFF chunks that break the hard binding of the delivered file). This is our second machine-readable marking layer under EU AI Act Art. 50(2).
• Our signed manifests already carry this alg value in their c2pa.soft-binding assertion, with one block whose value is the identifier.
• A separate alg name is used because the payload scheme and the manifest repository are ours; the list has no SilentCipher entry yet.

Checks

• Validated against softbinding-algorithm-list.schema.json with jsonschema validate (sourcemeta, as in the CI workflow); identifier and alg are unique.
• identifier 60 is requested because 55-59 are taken or claimed by open PRs (Add com.quatvision.quatmark.1 (QuatMark keyed image watermark) #87, Add com.encypher.text.watermark.1 and com.encypher.text.fingerprint.1 (entries 57, 58) #88, Add com.damaizlabs.lanternist.1 (entry 59) #89); happy to take any number you assign.
• informationalUrl resolves and documents this algorithm: https://aidr.studio/provenance/watermark/
• softBindingResolutionApis: https://aidr.studio/api/c2pa/v1 implements the C2PA Soft Binding Resolution API 1.0.0 (GET /services/supportedAlgorithms, GET/POST /matches/byBinding, GET /manifests/{manifestId} as application/c2pa). Public, no account, exact identifiers only, rate limited. POST /matches/byContent is not offered: the watermark is decoded with the open SilentCipher model and queried by binding. A live example query is on the informational page.

[domguinard]

Approved during the WM TF meeting on October 28.