A sequence of operations that ensure protection of data. Used with a communications protocol, it provides secure delivery of data between two parties. The term generally refers to a suite of components that work in tandem (see below). For example, the 802.11i standard provides these functions for wireless LANs.

For the Web, SSL is widely used to provide authentication and encryption in order to send sensitive data such as credit card numbers to a vendor. Following are the primary components of a security protocol. See cryptography, information security, HTTPS, SSL, PCT and IPsec.

Access Control
Authenticates user identity. Authorizes access to specific resources based on permissions level and policies. See access control and authentication.

Key Management
Create, distribute and maintain the keys. See key management.

Encryption Algorithm
The cryptographic cipher combined with various methods for encrypting the text. See encryption algorithm.

Message Integrity
Ensures that the encrypted message has not been tampered with. See message integrity.