Witness Pro 0.6.0 released

Witness Pro 0.6.0 is out. It is a Pro release: the free packages @sweberdev/witness and @sweberdev/witness-react stay at 0.4.0.

What is in 0.6.0

• A new package, @weber-development/witness-sign. It writes a signed C2PA manifest into a file you generated. The manifest states that the content was made by a generative model (IPTC digital source type trainedAlgorithmicMedia) and names the model, binds itself to the exact bytes of the file with a hash, and carries your certificate chain. Anyone with a C2PA reader can check where the file came from and that nobody changed it afterwards.
• Your certificate, your key. Witness does not issue certificates and runs no signing service. You pass a PEM certificate chain and key; signing happens on your machine. ECDSA (P-256, P-384, P-521), Ed25519 and RSA-PSS keys work, and Witness checks before signing that the key matches the certificate and the chain is valid and in order.
• Six file types. PNG, JPEG, WebP, WAV and MP4/MOV/M4A. Large manifests are split over several JPEG segments, and the MP4 manifest is appended so the offsets in the file stay valid. Files that already carry a manifest are refused rather than overwritten.
• Checked against the reference reader. Signed files verify with verifyC2pa from the scanner and with the c2pa-rs reference reader, and a changed byte is caught as a broken hash.

npx witness-sign generated/*.png --cert signer-chain.pem --key signer.key \
  --model "Image Model X" --model-version 3

import { signC2pa } from "@weber-development/witness-sign";

const { file } = signC2pa(bytes, {
  certificate: chainPem,
  privateKey: keyPem,
  model: { name: "Image Model X", version: "3" },
});

A word on trust

A signature is valid when the manifest and the file match. Whether a reader shows the signer as trusted is a separate question: Adobe's Content Credentials viewer and others only trust certificates from the C2PA trust list. With a certificate you made yourself, the file verifies but the signer is reported as not recognised. For content you publish, get a signing certificate from a CA on that list. A signature also does not fulfil Article 50 on its own; it is one way to mark content that the Code of Practice points to.

Not in this release: MP3, replacing or extending an existing manifest, and a signed timestamp. See the signing docs, the scanner docs for verification, and the Witness page for the Pro edition.