feat: Register WritersLogic CPOP ZWC text watermark (ID 29)#45
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Add zero-width character (ZWC) watermark algorithm for text content (text/plain, text/markdown, text/html). Embeds HMAC-SHA256 tags as invisible Unicode characters at deterministic word-boundary positions, binding document content to CPOP proof-of-process authorship evidence. Part of the CPOP protocol (draft-condrey-cpop-protocol).
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The ZWC watermark registration in PR #45 is the content binding layer for CPOE — it complements the process evidence work in #2009. Now that crJSON is merged, the soft binding results from this watermark have a standardized JSON representation too. |
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Will be discussed for potential merge at 4/15 WM TF
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Summary
Registering a zero-width character (ZWC) watermark algorithm for text content on behalf of WritersLogic.
com.writerslogic.zwc-watermark.1text/plain,text/markdown,text/htmlAlgorithm Description
Embeds a truncated HMAC-SHA256 tag as invisible zero-width Unicode characters (U+200B, U+200C, U+200D, U+FEFF) at deterministic word-boundary positions selected via HMAC-seeded Fisher-Yates shuffle. Each ZWC encodes 2 bits; 32 ZWCs produce a 64-bit tag that binds the document content hash and Merkle Mountain Range root to the authorship evidence chain.
The watermark enables blind extraction (no original required), survives copy-paste and re-encoding, and is intentionally invalidated by content modification — content changes require re-attestation under the CPOE proof-of-process protocol.
This is the first text-only soft binding algorithm in the registry, complementing the existing image/audio/video watermarks.
Context
Part of the CPOE (Cryptographic Proof-of-Effort) protocol implementing draft-condrey-cpop-protocol. The algorithm is open-source under AGPL-3.0 at writerslogic/cpoe.
Checklist
softbinding-algorithm-list.schema.json)alguses entity-specific namespace (com.writerslogic.*)identifieris next sequential (29)contactemail providedinformationalUrlprovided