Information security in noisy environments

Information security is endangered: · by presence of a noise during data transmission, which is the consequence of the nature of the transmission channel, · in memory systems, mainly caused by write endurance or aging. Nowadays communications demand security of transmitted or memorized information in many applications, which means application of different cryptographic mechanisms. Security is mainly interfered during the transmission over the channel, which becomes even a bigger problem if wireless transmission is used, because of a very noisy environment. Even more, a difference cannot be made, if the wrongly received data is a consequence of the attack on the channel or a noisy transmission lerrors in a memory system. Channel codes are standard components of the receiver in communication transmission systems, as well as in some memory systems, which use redundancy for the recognition and correction of errors that occur during the data transfer over a noisy channel. Although algorithm for channel decoding are very strong, there is always a remaining bit error rate after channel decoding depending on the channel characteristics, i.e. the signal-to-noise-ratio. Therefore remaining bit errors cause the rejection of secured messages, and loss of transmitted-information. Many applications in communication transmission systems use no ARQ mechanisms for correction of the remaining errors by repetition of the message, which may be caused by a very low SIN, which will again produce a message with errors, by real time requirements or by one way communication, which is used in deep space or broadcast applications. Standard ways of data verification relies on a hard verification condition that no errors are allowed in the secured received data. This condition can be very hard fulfilled, despite existence of numerous effective channel decoding techniques. Therefore alternative security algorithms and verification techniques should be applied.