Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.

PRIVATE CHAT CRYPTOGRAPHY

    Fixed encryption: RFC 9980 ML-KEM-1024 + X448, OpenPGP v6.
    Signing: ML-DSA-87 + Ed448, OpenPGP v6.
    Sequoia 2.4.2 + OpenSSL 3.6.5. No algorithm substitution or advisory exception.
    Superseded RustCrypto backend is not selected.

    Provides purpose-specific identities, Argon2id/AES-256-GCM protected files,
    detached authentication proofs, signed two-recipient messages, bounded
    verified history batches, compatibility probe. Native Rust and browser WASI
    share code. Standalone CLI: one JSON request on stdin; empty stdin runs probe.
    Browser WASI has no filesystem/network access. Private requests stay in local
    memory; never send them to server.

    ../../docs/CHAT-APPLICATION.txt: formats, setup, tests, backups, limits.
    ../../docs/CHAT-PRODUCTION.txt: packaged HTTPS.
    ../../docs/CHAT-OPENSSL-MIGRATION.txt: backend decision, source hashes,
    build flags, FFI/capability limits, reviewed dependency exceptions.
    Experimental. Compatibility tests are not an application security audit.

CHECK FROM WORKSPACE ROOT

        cargo test --locked -p stack-chat-crypto
        cargo run --locked -p stack-chat-crypto
        sh infra/chat/build-openssl-wasi.sh
        PLAYWRIGHT_BROWSERS_PATH="$PWD/.tools/browsers" npm run test:crypto
        cargo stack check

    Native build: OpenSSL >=3.5 development files, libclang.
    Cross-build host: x86_64 GNU/Linux. Browser tooling excluded from archives
    and releases; TypeScript tests and locked toolchain declarations remain public.
    Probe uses public fixture credentials and temporary in-memory identities.
    It never opens root .env or uses canonical RSA key.