Post-quantum
Socketchat gives message contents post-quantum protection, on by default. Post-quantum means safe against a future quantum computer: messages someone records today stay confidential even if such a computer arrives later.
Post-quantum cryptography is encryption designed to stay secure against a large quantum computer, a kind of computer that could break the key exchanges most encryption relies on today. No such computer exists yet, but traffic recorded now could be opened once one does.
Recording encrypted traffic today in order to decrypt it later has a name: harvest now, decrypt later. Post-quantum key exchange is the answer to it.
The best known is ML-KEM, which the US National Institute of Standards and Technology (NIST) published in August 2024 as FIPS 203. NIST says ML-KEM "is believed to be secure, even against adversaries who possess a quantum computer."
A quantum-resistant method can pair a post-quantum algorithm with X25519, a widely used classical key exchange. That pairing is called a hybrid, and it is never weaker than X25519 alone. NIST post-quantum encryption standards are what Socketchat's suite builds on.
Socketchat does it inside MLS (Messaging Layer Security), the standard for encrypted group chat published as RFC 9420. By default, every new room uses an MLS cipher suite whose key exchange pairs ML-KEM-768 with X25519.
In MLS a sender encrypts a message once and the server copies it to every member. Keys change with every change to a room and at least once a week, so a stolen key stops unlocking new messages.
ML-KEM-768 together with X25519, in the MLS cipher suite MLS_128_MLKEM768X25519_AES128GCM_SHA256_Ed25519. Messages and files are then encrypted with keys from that exchange.
Socketchat uses OpenMLS, an open-source MLS library written in Rust, and has no home-made cryptography.
Message contents and files: what you write and what you send. Message contents recorded today stay confidential even against a future quantum computer.
Is Socketchat safe? lists everything the encryption covers and what the server can still see.
Signal announced PQXDH on 19 September 2023. It combines X25519 with CRYSTALS-Kyber, a post-quantum algorithm, and Signal says it "protects messages exchanged on Signal against the threat of a future quantum computer."
Socketchat brings post-quantum protection to group chat on a server you run yourself.
More questions
MLS is an internet standard for end-to-end encrypted group chat, published by the Internet Engineering Task Force (IETF) in 2023 as RFC 9420. A group shares keys that change whenever someone joins, leaves or refreshes their keys.
Because encrypted traffic can be recorded today and kept. If a large quantum computer arrives later, messages protected only by today's key exchanges could be opened then.
Yes. New rooms use the post-quantum cipher suite by default, with nothing to switch on.
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/sachio222/socketchat_v4/releases/latest/download/socketchat-installer.sh | shpowershell -ExecutionPolicy Bypass -c "irm https://github.com/sachio222/socketchat_v4/releases/latest/download/socketchat-installer.ps1 | iex"brew install sachio222/tap/socketchatOpen a new terminal when it finishes.
Then start a server with socketchat server init --host chat.example.com and socketchat server run, and open port 7444. Quick start on the home page.
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