Defense-in-depth against XSS for a client that holds storage credentials in
memory. The critical directive is a strict script-src: 'self' + the hash of the
inline theme-bootstrap + the nostr-tools CDN fallbacks, with no 'unsafe-inline'
or 'unsafe-eval' (verified no bundle uses eval/Function/wasm). This blocks
injected script/object elements, inline handlers, and base-tag hijack, so an
injected payload cannot run and read the in-memory storage master key, the
signer, or DM plaintext. connect/img/media stay broad because relays, R2/S3
endpoints, and video/thumbnail URLs are user/content defined; worker-src allows
blob: for the WebTorrent module worker. Applied to index.html and embed.html.
Test (tests/csp-policy.test.mjs) locks the inline-script hash to script-src and
asserts script-src stays strict (no unsafe-inline/eval) with object-src 'none'
and base-uri 'self'.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
