# Signed checkpoint primary references and source roles

Accessed: 25 October 2026. All Cedar ledger/group/checkpoint/trust evidence is synthetic. Public cryptographic seeds are official fixtures, never credentials. These references support primitives and library behavior; the D30 wire, trust policy, diagnostics and resource bounds are authored choices.

| Primary source | Version / directly read role | Boundary |
|---|---|---|
| [RFC8032](https://www.rfc-editor.org/rfc/rfc8032.html) | January 2017 informational; §§3–5 pure Ed25519, §7.1 TEST1/TEST2, §8 considerations | No D30 framing/trust-store/timestamp policy claimed as an RFC standard |
| [Verified RFC8032 errata](https://www.rfc-editor.org/errata_search.php?rec_status=0&rfc=8032) | EID5968 verified27 January 2026 aligns scalar endpoints0<=S<L with §5.1.7 | No custom scalar or curve primitive written here |
| [W3C Web Cryptography Level2](https://www.w3.org/TR/webcrypto/) | 22 April 2025 First Public Working Draft §25: Ed25519 sign/verify/raw import and noted small-order implementation differences | Draft status retained; actual runtime testing required, no universal browser-support claim |
| [PyNaCl1.6.2 release](https://github.com/pyca/pynacl/releases/tag/1.6.2) and [official changelog](https://github.com/pyca/pynacl/blob/main/CHANGELOG.rst) |1 January 2026; libsodium1.0.20-stable2025-12-31 build fixes CVE-2025-69277 valid-point mixed-order issue | Actual Python verification runtime pinned1.6.2; not unpatched1.0.20 |
| [libsodium point-validation API](https://libsodium.gitbook.io/doc/advanced/point-arithmetic) and [maintainer fix explanation](https://00f.net/2025/12/30/libsodium-vulnerability/) | Canonical curve/main-subgroup/non-small-order checks; maintainer explains mixed-order bug and post 30 December 2025 stable fix | Vetted API called for A/R; no workaround curve arithmetic copied or implemented |
| [noble-curves2.4.0](https://github.com/paulmillr/noble-curves/releases/tag/2.4.0) and [versioned README](https://github.com/paulmillr/noble-curves/blob/2.4.0/README.md) | Official current release, explicit Ed25519 zip215:false, Point parsing/subgroup/small-order public APIs; audit scope recorded in upstream docs | Actual task-local locked2.4.0 code used; upstream audit is not an audit of this tutorial |
| [Node crypto](https://nodejs.org/api/crypto.html) | Official one-shot Ed25519 uses null algorithm; available operations depend on runtime/backend | Page identifies26.12.1; actual installed Node22.22.0 separately recorded. Learner TS uses actual WebCrypto plus noble. |
| [cryptography40.0.2 Ed25519](https://cryptography.io/en/40.0.2/hazmat/primitives/asymmetric/ed25519/) | Version-pinned raw key/sign/verify APIs | Diagnostic investigation only. Actual Python implementation uses patched PyNaCl, not cryptography40. |

Supports: exact pure-Ed25519 primitive and fixtures, documented import/verification APIs, current patch provenance and the explicit stronger profile. Limitations: no independently authenticated registry, source journals, custody system, real signing timestamp, non-equivocation or external retention supplied by these sources.

Historical example decision: **not useful** without retained bytes and independent key-policy evidence. RFC vectors are included as official test fixtures; Cedar is synthetic. The code and visual conclusions are author-derived and tested, not quoted from a standard. No full copyrighted specification is reproduced.