Eon Phoenix Post-quantum mail. Free, and yours to read the source of. Mail nobody can open. Free. Source open too.
Eon Phoenix is a mail client that speaks ordinary IMAP and SMTP and seals what it sends, so the mail server carries your correspondence without being able to read it. It is free and the source is public. There is no licence to buy, no seat count, and no account with us.
Three kinds of message, one inbox
- Email. Ordinary correspondence over IMAP and SMTP, to anyone with an address. Sealed when the other side can be sealed to, plain when it cannot — and the client says which it was.
- C-Mail. Confidential Mail: the same mail, in the same shape, that only ever goes out sealed. If the recipient publishes no key there is nothing to fall back to, so it is not sent — a confidential message is never quietly downgraded to a plain one.
- D-Mail. Discrete Mail: an always-encrypted, chat-shaped conversation that rides on the same email address. It appears as a thread rather than a list of messages, and it never leaves the encrypted path.
What the server never sees
Every protected message is sealed twice over. A post-quantum key encapsulation and X25519 both have to be broken before the body can be read, and the body itself is AES-256-GCM. Signing is ML-DSA-87 alongside Ed25519, applied before encryption, so a message that arrives is both unreadable in transit and attributable on arrival.
An identity does not carry one key. It publishes a set — ML-KEM-1024 and FrodoKEM-1344-SHAKE, each paired with X25519 — and the sender picks the strongest algorithm the recipient also publishes. Two families rather than one, so a break in either leaves the other standing.
Finding somebody's key
Codex is the directory that makes this work across domains: one keyserver per domain, publishing the key sets of the addresses it is responsible for. A client looks up the recipient's domain, fetches the set, and seals to it. No central registry, and no key exchange over the side channel that people actually use, which is the bit that has always broken PGP.
Where it runs
- Desktop. macOS, Windows and Linux. Go with a web frontend, built as one native binary.
- Codex. A server you run for your own domain, or a domain that runs one for you.
Free and open source
Phoenix was a closed beta with per-tester access codes. It is not any more: the builds and the source are public, and the releases live on GitLab. What we ask in return is what any project asks — report what breaks, and say what you needed and did not find.
Partners we are looking for
The client being free does not mean there is nothing to build on. Four kinds of partner, and each of them owns a piece we do not:
- Mail and hosting providers. You run Codex for the domains you already host, and key discovery works for your users without any of them having to do anything about it.
- Managed service providers and resellers. You roll Phoenix out across a client estate, keep it running, and charge for that. The software costs nothing; the work around it is worth paying for.
- Software vendors and integrators. You want the sealing layer or D-Mail inside a product of your own. That conversation is about interfaces, and it is one we would rather have before you have built around a guess.
- Packagers. Distribution repositories, internal app stores, managed device fleets — anywhere a build has to arrive through a channel that is not a download page.
What a partner gets from us: builds before they are announced, a direct line to the people who wrote the code, and a say in what the next release has to carry. Commercial terms depend on which of the four you are, so that part is a conversation rather than a price list. Get in touch and say what you have in mind.
Facts
Phoenix is mail program. It talk normal mail server, but it lock message first. Server carry your words, server cannot read your words. Free. Source open. No licence, no seat, no account with us.
Three kind of message
- Email. Normal mail, to anybody with address. Locked when other side can be locked to. Plain when not. Program say which one it was.
- C-Mail. Same mail shape, but locked always. No key on other side, message not go. Never go plain by accident.
- D-Mail. Always locked. Look like chat, not like list. Same address, different shape.
Why server cannot read
Message locked two time. New quantum lock and old X25519 lock. Both must break before anybody read. Body is AES-256-GCM. Name on message is ML-DSA-87 and Ed25519, put on before lock, so you know who send and nobody else can say they send it.
One person, many key. ML-KEM-1024 and FrodoKEM-1344. Two different family. Sender take strongest one that other side also have. One family break, other family still stand.
How find key
Codex is key book. Every domain run own book. Program ask book of person you write to, get key, lock message. No big central list. No sending key by hand, which is where old PGP always fall over.
Where it run
Mac, Windows, Linux. One core. Codex you run yourself, or your domain run it for you.
Free now
Before: closed beta, you need code. Now: no code. Build public, source public, release on GitLab. Tell us what break.
Partner we look for
Free program, still thing to build. Four kind of partner:
- Mail and host people. You run Codex for domain you already hold. Your user find key, user do nothing.
- Managed service, reseller. You put Phoenix on whole company, keep it alive, get paid for that. Program free. Work not free.
- Software maker. You want lock layer or D-Mail inside your own thing. Talk to us before you build around guess.
- Packager. Distro repo, company app store, managed phone. Place where build must arrive without download page.
What you get: build before anybody else see, direct line to people who wrote code, say in what next release carry. Price talk depend on which kind you are. Say hello. Early better than late.
Eon Phoenix — post-quantum end-to-end encrypted mail client with C-Mail and D-Mail conversations, plus Codex, a per-domain directory keyserver for key discovery. Transport is unmodified IMAP/SMTP. A desktop client (Go backend, web frontend) for macOS, Windows and Linux, built as one native binary. Free and open source; releases and source on GitLab. Partnership enquiries via /contact.html.
Message kinds
Cryptography
Distribution
Documentation
Full reference at docs.eoncore.eu/eon-phoenix/. Every page there is also Markdown: append index.md to its URL. All products in one file: docs.eoncore.eu/llms-full.txt.