Report a vulnerability privately, through GitHub's Report a vulnerability on this repository's Security tab, and not in an issue or a pull request. Say what the flaw is, where it is, and how to observe it; a failing case against conformance/check.mjs, or a seed and a signature, is enough. You will hear back within five working days with whether it is confirmed and what the fix will be.

archon is an identity floor: Ed25519 key bytes, one canonical way to spell a key as text, the SPKI and PKCS-8 codecs, domain-separated signing, and a proof-of-possession login scheme. It is the layer a caller trusts to say these bytes are that key and this signature is that key's. A way to make it say either falsely is a security report.

Concretely, in any of the three cores:

• A signature that verifies against a message or a key it was not made for — including across a domain separator, which exists precisely to keep one context's signature from counting in another.
• A key text, PEM or SPKI encoding that round-trips to different bytes than it was built from, or that is accepted when it is malformed. Length, prefix and alphabet are part of the grammar, not decoration.
• A divergence between the cores. Rust, Go and TypeScript are held to one oracle in vectors/ on purpose: if they disagree about whether something is a valid key, a valid signature or a valid key text, that disagreement is itself the vulnerability, because a consumer's two ends may not be in the same language.
• In the login scheme: a statement that binds to an audience it was not issued for, a proof that replays, an offer that can be taken twice, or an authority payload that the scheme reads rather than passes through. The audience is configured and never read from the wire; a way to make the wire decide it is a report.
• Key material reaching a log, an error string, a terminal or a file it was not asked to be written to.

Custody is not here. Storing a key, encrypting it at rest, rotating it, running a root ceremony, or deciding when a key is retired — none of that is archon's, and a flaw in how a consumer keeps a key is reported to that consumer. archon key writes a file you name and reads a file you name; it manages nothing.

Authority is not here. What a key is allowed to do is the law layer's question. AdmitAuthority hands the authority payload to the consumer without reading it. A flaw in what a consumer admits is reported to that consumer.

The conformance harness and the vector tooling are developer tooling that runs on a checkout's own files; a flaw in them is a bug.

archon is pre-1.0. The latest minor release is supported, in all three languages together; a fix ships as a new release across the cores rather than a patch to one of them.