swarmauri_cipher_suite_pep458 0.2.0.dev4

PEP 458 policy and algorithm definitions for Swarmauri cipher suites

---

swarmauri_cipher_suite_pep458

swarmauri_cipher_suite_pep458 captures the policy surface and algorithm registry that PEP 458 describes for securing Python package repositories. The suite models canonicalization, allowed algorithms, role thresholds, and metadata lifetimes so Swarmauri services can negotiate the same expectations when they sign or verify TUF metadata.

Highlights

• Explicit role policies – Encodes recommended thresholds, expiration windows, and algorithm selections for the canonical root, targets, snapshot, and timestamp metadata roles.
• Deterministic defaults – Advertises TUF canonical JSON (tuf-json) as the canonicalization format and returns Ed25519 as the default online algorithm while still supporting RSA-PSS-SHA256 for offline roots.
• Descriptor normalization – Produces rich normalized descriptors containing the signer implementation hint (swarmauri_signing_pep458.Pep458Signer), canonical preferences, and caller-specified policy overrides.
• Compliance metadata – Surfaces machine readable notes indicating PEP 458 and TUF compatibility, enabling automated linting and negotiation between components.

Installation

Using uv

uv add swarmauri_cipher_suite_pep458

Using pip

pip install swarmauri_cipher_suite_pep458

Quick Usage

from swarmauri_cipher_suite_pep458 import Pep458CipherSuite

suite = Pep458CipherSuite()

print(suite.features())
# {'suite': 'pep458', 'version': 1, ...}

descriptor = suite.normalize(op="sign", params={"role": "targets", "threshold": 2})
print(descriptor["mapped"]["provider"]["signer"])
# 'swarmauri_signing_pep458.Pep458Signer'

Combine the descriptor with instances of Pep458Signer to build automated pipelines that enforce PEP 458's online/offline separation.

Role Guidance

Role	Default Alg	Threshold	Recommended Expiration
root	RSA-PSS-SHA256	2	P365D
targets	Ed25519	1	P90D
snapshot	Ed25519	1	P14D
timestamp	Ed25519	1	P1D

These defaults mirror the best practices described in PEP 458, but you can override them by passing parameters to normalize or adjusting the resulting policy document.

Relationship to the Signer

This package pairs with swarmauri_signing_pep458, which implements the detached signature algorithm itself. The cipher suite surfaces metadata while the signer performs the cryptographic operations.

Development

• Format the code with ruff format . and lint with ruff check . --fix.
• Add or update unit tests alongside policy changes to validate normalization and feature reporting.
• Document any new role guidance in both the README and the policy() payload so downstream systems stay synchronized.

License

This project is licensed under the Apache License 2.0.