VPN (Virtual Private Network) is a technology that establishes secure encrypted connections over public networks. The working principle of VPN is to create an encrypted tunnel between the user's device and the VPN server, through which all data traffic is transmitted, thereby protecting data confidentiality and integrity.
Core components of VPN include:
- VPN Client: Software installed on user devices, responsible for establishing and managing VPN connections
- VPN Server: Receives and processes encrypted connection requests from clients
- Tunnel Protocol: Defines how to encapsulate and transmit encrypted data over public networks
- Encryption Algorithm: Protects the security of data transmission
Main functions of VPN:
- Data Encryption: Uses encryption algorithms like AES, ChaCha20 to protect data
- Authentication: Ensures only authorized users can access the VPN network
- Tunneling: Creates virtual private channels over public networks
- IP Address Hiding: Replaces user's real IP with VPN server's IP
Common VPN protocols:
- PPTP: Older protocol with lower security
- L2TP/IPsec: Combines L2TP and IPsec, offers good security
- OpenVPN: Open-source protocol with high security and strong configurability
- IKEv2: Fast reconnection, suitable for mobile devices
- WireGuard: Next-generation lightweight protocol with excellent performance
VPN application scenarios include remote work, protecting public Wi-Fi security, bypassing geo-restrictions, and protecting privacy.