IPSec defines two types of encryption algorithms. One type, symmetric encryption, encrypts our bulk data. The other type of algorithm, asymmetric, encrypts very small amounts of data.
Symmetric and Asymmetric EncryptionThe end result required of IPSec is confidentiality, which is provided by encrypting data. It is the easiest part of IPSec to accomplish. To encrypt data, the plaintext data is broken into pieces and inserted along with an encryption key into the encryption algorithm. The output of the algorithm is ciphertext and is sent to the peer. The peer performs the same algorithm in reverse using the same key. The end result of encryption is that the person who has the shared secret key is the only person who can decrypt the ciphertext back into its plaintext form. Encryption algorithms come in two flavors:
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