Trojan and Shadowsocks 2022

Trojan and Shadowsocks 2022 are the fallback modes of Colitu Adaptive Connect. They wait on every server so you can still connect when Hysteria2 and VLESS don't get through.

#What is Trojan?

Trojan is a proxy protocol that runs over TCP and encrypts traffic with TLS. In Colitu it runs on the open source sing-box core. The idea is simple: make VPN traffic look like HTTPS, the most common kind of traffic on the internet.

#How it passes as HTTPS

• The connection starts with a TLS handshake, just like a normal HTTPS visit to a website.
• A client that brings the right password gets its traffic into the tunnel.
• Without the right password the server gives no VPN-specific answer: to someone probing it, it is just a server that speaks TLS.

#When Adaptive Connect uses Trojan

• Android and iOS: it is tried fourth, after Hysteria2, VLESS Reality and VLESS XHTTP.
• Windows and Linux: after Hysteria2, the TCP modes are sorted by the connect time measured to the server. If Trojan answers faster, it can move up the line.

Whichever mode your connection ends up on, it is encrypted, and you never need to pick the mode yourself.

#Shadowsocks 2022: the last fallback

On Android and iOS, Shadowsocks 2022 is the last mode tried; on Windows and Linux it is ranked together with the other TCP modes by measured connect time.

• Unlike the other modes it doesn't use TLS; it protects traffic directly with AEAD encryption (2022-blake3-aes-256-gcm).
• It includes replay protection: recorded packets sent again are rejected.
• In Colitu it runs on sing-box.

It is there so your connection can still be made when the other modes fail the health check.

#Security

• Trojan traffic is protected by TLS, Shadowsocks 2022 traffic by AEAD encryption.
• Connection details reach your app encrypted; server addresses, ports, passwords and keys are never published.
• Whatever mode is in use, Colitu's logging policy is the same: Privacy.

For the technical deep dive: colitu.com/protocols/trojan. All modes compared: How Colitu Adaptive Connect works