lockbitchat
c98a01b1d5
- Record voice notes in-browser, sent over the chunked AES-GCM file-transfer channel (per-file session key + signed SHA-256 integrity). - Captured as PCM and encoded to WAV for universal playback (incl. iOS/Safari); auto-accepted and played inline from an in-memory blob, never written to disk. - Composer mic button with live waveform + timer; desktop shows mic + send side by side, mobile swaps mic to send when typing. - CSP media-src now allows blob: so recorded/received audio can play. - Roadmap: Desktop Edition -> 5.0, new 5.5 'Secure Voice & Calls', later milestones shifted; version bumped to 5.4.5. - Update README, docs (security/API/cryptography), and CHANGELOG.
67 lines
2.2 KiB
Markdown
67 lines
2.2 KiB
Markdown
# Security Architecture
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## Current baseline
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| Area | Current behavior |
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| --- | --- |
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| Protocol | `4.1` with mismatch rejection |
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| Peer verification | mandatory manual SAS entry |
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| Transport | WebRTC over DTLS |
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| Privacy mode | optional TURN relay-only mode |
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| Message UI safety | incoming decrypted text sanitized before display |
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| File transfer | validated metadata, explicit consent, allowlist policy |
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| Voice messages | same chunked AES-GCM transfer as files; auto-accepted and played inline |
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| Local metadata | encrypted IndexedDB envelopes with migration |
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| Lifecycle | unified disconnect cleanup and bounded resource retention |
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## Verification state machine
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```text
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connection established
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↓
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shared keys derived
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↓
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deterministic SAS displayed
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↓
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manual out-of-band comparison
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↓
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local input validated
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↓
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peer confirmation received
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↓
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verified session
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```
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The verified state is reached only when both local and remote confirmation flags are true.
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## File-transfer architecture
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1. sender emits metadata
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2. receiver validates name, size, type, and abuse limits
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3. receiver sees Accept / Reject prompt
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4. no receive buffers are allocated before acceptance
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5. sender transmits chunks only after acceptance
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6. completed received buffers are retained within a bounded window
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## Voice messages
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Voice notes reuse the file-transfer pipeline, so they inherit its per-file
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AES-GCM session key, chunking, and SHA-256 integrity check. Differences from a
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regular file:
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1. audio is recorded in-browser and encoded as PCM/WAV before sending
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2. duration and a downsampled waveform travel as **unsigned** presentation
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metadata; the audio bytes remain integrity-protected by the signed file hash
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3. the receiver **auto-accepts** voice transfers (no consent prompt) and plays
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them inline from an in-memory blob — nothing is written to disk
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## Disconnect cleanup
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The canonical disconnect path clears:
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- WebRTC channels and peer connection handles
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- timers, deferred retries, fake traffic, and decoy traffic
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- pending transfer state and consent waits
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- verification state and crypto/PFS state
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- React file-transfer callbacks and stale UI transfer state
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