OpenWeb is a proprietary protocol developed by Astrill in 2009. It is based on TCP and is encrypted in multiple security encryption and authentication layers. It is a connection-less protocol, so you can switch between servers within seconds, without waiting for VPN software to reconnect. It is very lightweight and performs well in countries with elevated censorship.
OpenWeb is very hard to detect by DPI (deep packet inspection). Traffic looks like regular website browsing, so nobody can say you are using Internet over VPN. OpenWeb traffic is encrypted with AES-256, which is an industry standard.Read more about OpenWeb protocol
StealthVPN is another proprietary protocol by Astrill. It is inspired by OpenVPN and performs an additional obfuscation of traffic which makes it undetectable for automated firewall systems. StealthVPN is very stable and it can work with both UDP and TCP modes. Just like OpenWeb, it is only available with official Astrill VPN software.
StealthVPN data streams are protected with AES-256 and authentication is done with certificates. This makes the protocol not only very secure, but also very stable. Connection is kept alive throughout the duration of a session and all traffic from your computer is routed through Astrill VPN, so there are no IP or DNS leaks.Read more about StealthVPN
WireGuard is an extremely simple yet fast and modern VPN protocol that utilizes very strong cryptography. It aims to be faster, simpler, leaner, and more useful than IPSec, while avoiding the massive headache. It intends to be more performant than OpenVPN. WireGuard is designed as a general purpose VPN, fit for many different circumstances.
WireGuard uses state-of-the-art cryptography, like the Noise protocol framework, Curve25519, ChaCha20, Poly1305, BLAKE2, SipHash24, HKDF, and secure trusted constructions. It makes conservative and reasonable choices and has been reviewed by cryptographers. WireGuard is the result of a lengthy and thoroughly considered academic process, resulting in the technical whitepaper, an academic research paper which clearly defines the protocol and the intense considerations that went into each decision.Read more about Wireguard
OpenVPN is a very flexible protocol that is widely supported across platforms. It can work over UDP, which provides fast speed, or TCP, which provides higher reliability and stability. You can connect to OpenVPN with 3rd party clients and set up VPN connection without the need of any Astrill software. Since OpenVPN does not aim to hide its traffic, it is easily detectable by automated firewall systems and frequently blocked and throttled. E.g. it is often blocked in China.
OpenVPN is an open-source protocol which is often analysed by security experts from all around the world for vulnerabilities and exploits and it is frequently updated and improved. It can use wide range of encryption algorithms like AES, BlowFish, Camelia and others. The protocol is very secure.