Extends the previously verify-only ed25519.c with ed25519_keygen() and ed25519_sign() per RFC 8032 5.1.5/5.1.6, reusing every point-arithmetic primitive verify already had -- only seed expansion/clamping and per-message nonce derivation are new. Signing is deterministic; only keygen ever touches entropy, via a caller-supplied seed (virtio_rng, Phase A) -- keygen still generates nothing itself. New scalar_muladd() (scalar25519.c) for signing's S = (k*a + r) mod L, the one scalar op verify never needed. Schoolbook multiply into a u128 wide accumulator with one final carry pass -- deliberately the same shape as fe25519.c's existing multiply, which has a documented history of a real bug from carrying mid-accumulation instead of in one pass. Verified against an independent implementation, not self-consistency: a throwaway host harness against Python's cryptography library (OpenSSL- backed) across 6 trials (5 random seed/message pairs + the empty-message case) produced byte-for-byte identical pubkeys and signatures every time. Clean compile on all three architectures and a full 3-arch QEMU acceptance boot, conservation intact, no panics or guest errors. Nothing calls the new functions from the live kernel path yet -- that's Phase C (the MINT word itself), still open, documented in FABRIC-3.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01U14ET9CWAtbQMbYqomKgXd
capsules/
FORTH personality files loaded by the VM at boot. A capsule is an immutable, content-addressed payload; its XXHash64 hash is its identity. Any mutation changes the hash and the birth protocol rejects the image.
Key files
| File | Type | Purpose |
|---|---|---|
init.4th |
(m) MAMA_INIT |
Default Mama VM personality — loaded at LBN 2048 |
ACL.4th |
user | Word-level ACL system; self-activating at boot |
zuse.4th |
user | Bootstrap superuser; loaded by ACL.4th |
doe.4th |
user | DoE workload words (EXEC-DOE) — opt-in |
init-0.4th … init-9.4th |
(p) |
Numbered personality variants |
init-l8-*.4th |
(p) |
L8 Jacquard mode variants (stable/volatile/diverse/temporal/transition/omni) |
hermes/init.4th |
(p) |
Hermes baby VM personality |
artemis/init.4th |
(p) |
Artemis baby VM personality |
Block namespace
Block ranges are shared across all loaded capsules — collisions cause silent word-definition overwrites.
| Range | Owner |
|---|---|
| 2048–2099 | init.4th |
| 2100–2199 | doe.4th |
| 3000–3999 | workload capsules |
| 4000+ | user-defined (ACL.4th, zuse.4th, …) |
Each block is limited to 1024 bytes. Verify with wc -c before committing.
See also
experiments/bare_metal/README.md— DoE protocols and block namespace rulesdocs/03-architecture/word-acl/DESIGN.md— ACL system designtools/mkcapsule.c— assembles capsules intocapsule_generated.c- Project root