Orkuncakilkaya
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The security-sensitive counterpart to the fast, non-cryptographic Hash.* library: standard, test-vector-backed hashing for signed saves and message integrity, kept in its own namespace so nobody reaches for the wrong tool. Crypto.sha256(s) SHA-256 -> 64-char lowercase hex Crypto.hmac_sha256(key, msg) HMAC-SHA256 -> 64-char hex Crypto.verify_hmac(key, msg, mac) recompute + constant-time compare -> bool Crypto.hex(s) lowercase hex of a string's bytes Crypto.ct_equal(a, b) constant-time string equality The primitives are implemented from scratch in plain integer LLVM IR (FIPS 180-4 / RFC 2104): no libc crypto, no data-dependent branches in the compression rounds, so a given input hashes to the same 32 bytes on every platform and run. Digests are returned as hex strings, not raw bytes, because a `str` is null-terminated and a raw digest can contain a NUL. MAC checks use a non-short-circuiting compare so timing does not leak how much of a forged tag was correct. Emitted on demand via g_uses_cryptort, mirroring the emit_hash prelude gate. Scoped to the deterministic, known-answer-testable core; OS-backed random_bytes (the one piece that can't be validated by test vectors) is left for a follow-up. Tested against published SHA-256 vectors (empty/"abc"/fox + 55/56/64-byte multi-block padding) and HMAC-SHA256 vectors; wired into the self-host suite as `crypto`. Docs: a new Crypto section with honest "what this protects / does not" guidance, one page per method, all fences checked and in the inventory. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
1.5 KiB
| id | title | order |
|---|---|---|
| crypto | Crypto | 6 |
Secure, test-vector-backed hashing for the handful of security-sensitive things a game actually does: signing a save or leaderboard payload so casual tampering is detectable, and verifying that a network message or token was not forged by someone who does not hold the key. This is the deliberate counterpart to the fast Hash library — same idea, opposite trade-off. Hash is fast and reversible and must never guard anything; Crypto is SHA-256 and HMAC-SHA256 implemented to the standard, so the algorithms are the ones with published known-answer tests rather than anything home-grown.
Digests are returned as lowercase hex strings, not raw bytes — a str is null-terminated and a raw digest can contain a zero byte, so hex is the form you can print, store, and compare directly.
What this is not: it is not DRM and it is not unbeatable anti-cheat. A client-side game cannot keep a secret from the machine it runs on — a determined owner can always read the key out of the binary. Use it to make casual tampering detectable and to authenticate messages between parties who share a key. To verify a MAC always use Crypto.verify_hmac (a constant-time check), never ==, which leaks how much of a guessed MAC was correct.