Security details

Security features in detail

The protocol, primitives, and protections behind your BigCatVPN connection — WireGuard, DNS leak protection, and a kill switch, without overcomplicated settings.

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WireGuard Protocol

Modern WireGuard VPN technology

BigCatVPN uses WireGuard, a modern VPN protocol built for security, speed, and simplicity.

Lean and efficient: WireGuard is designed for low overhead — a small codebase and minimal in-kernel work compared with older protocols like OpenVPN and IPSec.
Cryptographically Secure: Built with modern cryptography including ChaCha20, Poly1305, Curve25519, and BLAKE2s for state-of-the-art security.
Simple & Reliable: With only ~4,000 lines of code (vs 400,000+ for OpenVPN), WireGuard is easier to review and has a smaller attack surface.
Kernel-Level Performance: Runs in the kernel space for maximum performance, reducing latency and improving throughput compared to user-space VPN implementations.

Modern Cryptography

Vetted Cryptographic Primitives

WireGuard uses a fixed, well-studied set of cryptographic primitives: ChaCha20-Poly1305 for encryption, Curve25519 for key exchange, and BLAKE2s for hashing.

C20

ChaCha20

Modern stream cipher used by WireGuard to encrypt your traffic.

P1305

Poly1305

Message authentication code that ensures data integrity. Prevents tampering and verifies that data hasn't been modified.

C25519

Curve25519

Elliptic curve cryptography for key exchange. Provides a 128-bit security level with strong forward secrecy.

B2s

BLAKE2s

Cryptographic hash function used for keyed authentication inside the WireGuard handshake.

PFS

Perfect Forward Secrecy

Each session uses fresh keys, so if one session is compromised earlier sessions remain protected.

Advanced Security Features

Comprehensive Protection

BigCatVPN goes beyond basic encryption to provide multiple layers of security that protect you from every angle.

Kill Switch: Automatically blocks all internet traffic if your VPN connection drops, preventing any accidental data leaks or IP exposure.
DNS Leak Protection: All DNS queries are handled through our secure servers, preventing your ISP from seeing which websites you're trying to access.
Split Tunneling: Choose which apps and websites use the VPN and which bypass it, giving you granular control over your network traffic.
IPv6 Leak Protection: Comprehensive IPv6 support with leak protection ensures your IPv6 traffic is also secured and routed through our VPN servers.

Security Architecture

How BigCatVPN Protects You

Our multi-layered security approach ensures your data is protected at every step, from your device to our servers and beyond.

Device-level security

BigCatVPN creates a secure tunnel at the operating-system level so network traffic from your device is encrypted before it leaves your machine.

What this means: Other apps on your device can't bypass the tunnel — traffic is encrypted and routed through our servers.

Network-level protection

Your encrypted data travels over the public internet inside a WireGuard tunnel to our VPN servers, where it exits to its destination.

What this means: A useful layer of protection on shared networks like public Wi-Fi.

Server-level posture

VPN servers are configured to retain as little data as possible — no browsing activity, DNS queries, or originating IP address used for the connection.

What this means: There's very little user data on a VPN server in the first place.

Tunnel encryption

Traffic between your device and our VPN server is encrypted with ChaCha20-Poly1305 inside the WireGuard tunnel.

What this means: Anyone observing the network between you and the server sees encrypted traffic, not your activity.

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