archon core — Python

The identity floor in Python: Ed25519 key bytes, one canonical text spelling, the SPKI and PKCS-8 codecs, and domain-separated signing.

pip install bitspark-archon-core

The distribution is bitspark-archon-core; the import is archon_core. The prefix is a registry name only — PyPI, like crates.io, has a single flat namespace.

from archon_core import (
    public_key_from_seed, encode_key, sign_in_domain, verify_in_domain,
)

seed = bytes(range(32))
pub  = public_key_from_seed(seed)

encode_key(pub)
# 'ed25519:03a107bff3ce10be1d70dd18e74bc09967e4d6309ba50d5f1ddc8664125531b8'

sig = sign_in_domain(seed, "example.v1", b"hello")
verify_in_domain(pub, "example.v1", b"hello", sig)   # True
verify_in_domain(pub, "other.v1",   b"hello", sig)   # False — domains do not cross

What it is

Two questions and no others: are these bytes that key, and is this signature that key's. Authority and custody belong to their own layers — see the repository README.

Agreement is the claim

This core is held to the same hand-authored oracle as the Go, Rust and TypeScript cores — 60 cases in vectors/identity.json, recomputed rather than echoed. If it disagrees with the others about whether something is a valid key, signature or key text, that disagreement is the defect.

Two places where Python needed care to agree, both recorded in the source:

• sign_in_domain is Ed25519ph with the domain as the RFC 8032 §5.1 context. cryptography cannot express it — it offers only pure sign(data). This package binds PyCryptodome, which can.
• Small-order public keys are rejected. PyCryptodome's verifier accepts them; Go's crypto/ed25519 and ed25519-dalek do not. archon's profile is to reject, so verify checks [8]A against the identity using the library's own point arithmetic. Without it, two oracle cases pass in Python and fail everywhere else.

Verification

Signing raises rather than silently signing raw: an empty domain, or one over 255 bytes, is an error. Verification is total — every shape failure returns False, so a caller cannot mistake malformed for valid.

License

Apache-2.0. See LICENSE and NOTICE.