ChaCha20

ChaCha20 is a stream cipher widely used in modern secure connections, typically combined with the Poly1305 authenticator as ChaCha20-Poly1305 to both encrypt and verify data. It is a peer to AES-256 in strength, but its big practical advantage is speed in software: where AES is fastest on CPUs with hardware acceleration, ChaCha20 stays quick everywhere, which makes it a strong choice on phones and lower-powered devices that lack an AES instruction set.

This is why ChaCha20 features prominently in the protocols behind modern VPNs, including WireGuard, and in TLS 1.3. When the s4m VPN secures your traffic, a cipher of this class keeps the payload confidential regardless of the device you connect from. As with any cipher, the encryption is only as safe as the key exchange around it, so pairing it with perfect forward secrecy matters just as much as the cipher choice. In short, ChaCha20 and AES-256 are both excellent; the right one depends mainly on your hardware.

ChaCha20 features prominently in WireGuard and TLS 1.3, which is why it matters for anyone connecting from a phone or a low-powered device: it stays fast where AES depends on hardware acceleration. When the s4m VPN secures your traffic, a cipher of this class keeps the payload confidential on any device. As always, the encryption is only as safe as the key exchange, so pairing it with perfect forward secrecy matters as much as the cipher itself.