In practice, the security of a Quantum Key Distribution (QKD) system relies not only on quantum mechanical principles, but it also significantly relies on the physical implementation of the protocol. Nowadays, technological detector loopholes of QKD systems have been demonstrated, and some successful attacks that exploit vulnerabilities of the Avalanche Photo Diodes (APD’s) have been performed....

In recent years, researchers have explored using unique radio propagation characteristics between two devices for extracting symmetric keys. However, the state-of-the-art has the following limitations: (i) paying more attention to only when the two devices are in communication range, and (ii) generating keys only when the devices are in motion. Secret key generation for devices which are not in...

In this paper we consider a digital watermarking application where multiple parties can embed additional information using their watermark embedder. These parties are not supposed to influence each other and each watermark detector needs to be able to decode the information embedded by any of the embedder systems. One approach would be to use a single secret key and to assign part of the payloa...

Quantum cryptography (or quantum key distribution) is a state-of-the-art technique that exploits the properties of quantum mechanics to guarantee the secure exchange of secret keys. This self-contained text introduces the principles and techniques of quantum cryptography, setting it in the wider context of cryptography and security, with specific focus on secret-key distillation. The book start...

In September 1996 Boneh, Demillo, and Lipton from Bellcore announced a new type of cryptanalytic attack which exploits computational errors to find cryptographic keys. Their attack is based on algebraic properties of modular arithmetic, and thus it is applicable only to public key cryptosystems such as RSA, and not to secret key algorithms such as the Data Encryption Standard (DES) . In this pa...

We address the problem of efficiently establishing a shared secret key over an open wireless channel in the presence of an active (jamming) adversary. A commonly employed technique in practice for key sharing is the cryptographic ellipticcurve Diffie-Hellman (DH) protocol; however, its communication cost in a jammed environment is very high. Hence, we employ novel physical-layer techniques to e...

A pseudonym provides anonymity by protecting the identity of a legitimate user. A user with a pseudonym can interact with an unknown entity and be confident that his/her identity is secret even if the other entity is dishonest. In this work, we present a system that allows users to create pseudonyms from a trusted master public-secret key pair. The proposed system is based on the intractability...

Two protocols for authentication based on symmetric key cryptography are described, where the verifier can be implemented in software completely, without the need for secure storage of any secret information. The protocols use a symmetric cipher in an asymmetric fashion: the verifier uses a verification key which is derived from a symmetric master key. Software only verification means that the ...

Passwords bootstrap symmetric and asymmetric cryptography, tying keys to an individual user. Biometrics are intended to strengthen this tie. Unfortunately, biometrics exhibit noise between repeated readings. Fuzzy extractors (Dodis et al., Eurocrypt 2004) derive stable symmetric keys from noisy sources. We ask if it is also possible for noisy sources to directly replace private keys in asymmetr...

This paper provides the Shannon theoretic coding theorems on the success probabilities of the impersonation attack and the substitution attack against secret-key authentication systems. Though there are many studies that develop lower bounds on the success probabilities, their tight upper bounds are rarely discussed. This paper characterizes the tight upper bounds in an extended secret-key auth...