The wiretap channel put forward by Wyner for many years. In this paper, we consider the situation that the wiretapper can not only view the channel output via a second noisy channel, but also can get some side information about the codeword that transmitted in the main noisy channel. The designer tries to build the encoder-decoder in such a way as to maximize the transmission rate R, and the eq...

We consider the MIMO wiretap channel, that is a MIMO broadcast channel where the transmitter sends some confidential information to one user which is a legitimate receiver, while the other user is an eavesdropper. Perfect secrecy is achieved when the the transmitter and the legitimate receiver can communicate at some positive rate, while insuring that the eavesdropper gets zero bits of informat...

Secure communication with feedback is studied. An achievability scheme in which the backward channel is used to generate a shared secret key is proposed. The scenario of binary symmetric forward and backward channels is considered, and a combination of the proposed scheme and Maurer’s coding scheme is shown to achieve improved secrecy rates. The scenario of a Gaussian channel with perfect outpu...

We analyze physical-layer security based on the premise that the coding mechanism for secrecy over noisy channels is tied to the notion of resolvability. Instead of considering capacity-based constructions, which associate to each message a sub-code that operates just below the capacity of the eavesdropper’s channel, we consider resolvability-based constructions, which associate to each message...

The aim of information-theoretic secrecy is to ensure that an eavesdropper who listens to the wireless transmission of a message can only collect an arbitrarily small number of information bits about this message. In contrast to cryptography, there are no assumptions on the computational power of the eavesdropper. Information-theoretically secret communication has been studied for many particul...

We overview the aims and the philosophy of modern cryptography. We exemplify this approach with the first shot at a definition of encryption scheme security, which we will develop later on in this class. We then give a classic definition given by Claude Shannon of perfect secrecy for an encryption. We show that various classic ciphers fail to satisfy this definition, but we also show a cipher c...

Recently, Liu proposed two authenticated multiple key exchange protocols using pairings, and claimed two protocols featured many security attributes. In this paper, we show that Liu’s protocols are insecure. Both of Liu’s protocols cannot provide perfect forward secrecy.

Recently, Tsai proposed an efficient nonce-based authentication scheme for session initiation protocol (T-SIP for short). However, the author shall show that T-SIP is vulnerable to perfect forward secrecy, password guessing attacks, and insider attacks.

The prominence of the wireless communication has been urging the monotonically increasing demand of security and privacy. In wireless systems, the notion of perfect secrecy of information with respect to illegitimate nodes can be ensured via physical layer security (PLS) techniques. Unfortunately, they can be made less effective if sourceeavesdropper wiretap channel is better than the main sour...