See Public Key Cryptographic Algorithm Note: by asymmetric, the key for encoding the digital data to be transmitted is entirely different from the code for decrypting the data at the receiving end. This is in contrast to symmetric key encryption, whereby the same key is used to encrypt and decrypt the data. Asymmetric is logistically more secure because it avoids transfer of the key between transmitter and receiver, whereby it could be intercepted. It is important to note that cryptographic methods to protect the confidential data are more critical for IT networks than for control networks. For IACSs, confidentiality is most critical for the authenticating and authorization stages during access control into a given IACS. Usually cryptography adds undesired latency to the IACS network, which is very undesirable for open and closed loop systems that must receive, manipulate, and send control data at a rate commensurate to an asset’s process dynamics. Consequently, availability and integrity are usually higher IACS cyber security objectives than is confidentiality. (3)
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Last modified at 12/29/2011 10:34 AM by Eric Cosman
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