Symmetric and Asymmetric Encryption

Abstract

All cryptosystems currently m use are symmetrm m the sense that they require the transmitter and receiver to share, m secret, either the same pmce of reformation (key) or one of a paLr of related keys easdy computed from each other, the key is used m the encryption process to introduce uncertainty to an unauthorized receiver. Not only is an asymmetric encryption system one in whmh the transmitter and receiver keys are different, but in addition it Is computatmnally mfeaslble to compute at least one from the other. Asymmetric systems make it possible to authent2cate messages whose contents must be revealed to an opponent or allow a transmitter whose key has been compromised to communmate m privacy to a receiver whose key has been kept secret--neither of which is possible using a symmetric cryptosystem. This paper opens with a brmf dmcussion of encryptmn principles and then proceeds to a comprehensive discussion of the asymmetric encryptmn/decryp tion channel and its application m secure communmations.