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IPSec Overview Part One: General IPSec Standards

Article Description

Virtual Private Networks (VPNs) are becoming required expertise for network and security engineers, and IPSec is the most commonly used protocol when implementing VPNs. In this first article of a five-part series on the Cisco implementation of IPSec, Andrew Mason delves into the components that make up the IPSec protocol suite.

Message Digest 5 (MD5)

Message Digest 5 (MD5) is a hash algorithm used to authenticate packet data. Cisco routers and the PIX Firewall use the MD5 hashed message authentication code (HMAC) variant that provides an additional level of hashing. A hash is a one-way encryption algorithm that takes an input message of arbitrary length and produces a fixed-length output message. IKE, AH, and ESP can use MD5 for authentication.

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