Table 5. Cisco Aironet 1140 Series Power Injector Product Numbers Product Number Product Description AIR-PWRINJ4= Cisco Aironet Power Injector for the 1140 Series (Spare) Power Supply A Cisco Aironet power supply is not included with the Cisco Aironet 1140 Series and may be purchased separately (Table 6). The AIR-PWR-B is the recommended power supply for the 1140 Series.
public-key encryption. Related Terms. A cryptographic system that uses two keys -- a public key known to everyone and a private or secret key known only to the recipient of the message. When John wants to send a secure message to Jane, he uses Jane's public key to encrypt the message. Jane then uses her private key to decryptit.
In symmetric systems the same key (the secret key) is used to encrypt and decrypt a message. Data manipulation in symmetric systems is faster than asymmetric systems as they generally use shorter key lengths. Asymmetric systems use public key to encrypt a message and a private key to decrypt it.Use of asymmetric systems enhances the security of communication. In colloquial use, the term  code  is often used to mean any method of encryption or concealment of meaning.ymmetric-key cryptography, where a single key is used for encryption and decryption. Symmetric-key cryptography refers to encryption methods in which both the sender and receiver share the same key (or, less commonly, in which their keys are different, but related in an easily computable way).