Asymmetric encryption requires each person to have one publicly known key and one private key, both of them unique to that individual. To send an encrypted message, the sender must look up the recipient's publicly known key and use it to encrypt the message, which can then be read only if it is decrypted with the recipient's private key. No keys need change hands using this technique, although it is more time-consuming than symmetric encryption. Many solutions combine the two strategies, using the public key to encrypt a secret key, which is used to encrypt the actual message. The most popular asymmetric algorithms are from RSA Data Security Inc., although agencies, unless they apply for a waiver, are required to use the symmetric Digital Encryption Standard.
Encryption has applications in many areas, including electronic commerce and message authentication.
This ensures that the purported message sender is the person who really sent the message and also that the message contents have not been altered. Paralon Technologies Inc. Encryption software packages such as Pretty Good Privacy are available free on the Internet. The voluntary program divides encryption keys into two components, one safeguarded by NIST, the other by the Treasury Department. But critics are wary of concentrating too much power in the government's hands.