A suite of protocols that provides secure communication over IP networks by encrypting and authenticating data packets. Operating at the network layer, IPsec can protect all IP-based traffic between participating devices, regardless of the applications generating that traffic.
IPsec supports two primary modes:
- Transport mode, which encrypts only the payload of IP packets.
- Tunnel mode, which encrypts the entire packet for secure communication between networks or endpoints. It uses protocols like Authentication Header (AH) for integrity and Encapsulating Security Payload (ESP) for encryption, and can authenticate peers using pre-shared keys or digital certificates.
Everyday use cases include Virtual Private Networks (VPNs), site-to-site encrypted links between data centers, and secure remote access for employees. IPsec is widely supported by operating systems, routers, and firewalls, making it a foundational technology for network security.
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