Abstract Authenticated Encryption is a cryptographic process of providing confidentiality and integrity protection of messages in a single pass without any support of conventional checksum, Message Authentication Code (MAC), or hash function. In this paper, at first, we show that how to construct the stream‐cipher‐based Authenticated Encryption environment, where the key‐stream is generated from any secure block algorithm like Advanced Encryption Standard. In order to do that, we introduce two stream‐cipher modes of Authenticated Encryption, namely, PFC‐CTR (Counter‐based Authenticated Encryption environment) and PFC‐OCB (OCB‐based Authenticated Encryption environment), which are quite robust against several active attacks, for example, message stream modification attacks, known‐plain‐text attacks, and chosen‐plain‐text attacks, and at the same time, they can also efficiently deal with some other issues like “limited error propagation” existing in several conventional stream‐cipher modes of operation like Cipher Feedback, Output Feedback, and Counter. Finally, we enforce the concept of Authenticated Encryption in the sense of data communication security of the wireless sensor network (WSN), Global Mobility Networks (GLOMONET), and Cloud Computing environment, where only encryption can guarantee both the privacy and integrity in a single pass with the assurance of reasonable computational overhead. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract It is highly desirable that a real‐time crypto system should be designed to offer a strong security level by assuring both the privacy and integrity together in the same podium. However, the conventional stream cipher modes of operation (counter (CTR), cipher feedback (CFB), and Output Feedback (OFB)), often used in several real‐time applications, are unable to prevent any unauthorized message modification, which may often lead to several active attacks. This article shows a way to construct the real‐time based Authenticated Encryption (AE) environment, where the real‐time key stream is generated from any secure block algorithm like Advanced Encryption Standard (AES). Accordingly, in order to demonstrate the principle of the real‐time based AE environment, here we introduce two modes of operations, namely integrity aware real‐time based counter (IAR‐CTR) and cipher feedback (IAR‐CFB) modes, where both the proposed modes of operations can guarantee to offer both the confidentiality and message integrity in a single pass without any Message Authentication Code (MAC) or even any kind of non‐crypto checksum Cyclic Redundancy Check (CRC) support. Besides, here we argue that both the proposed real‐time based AE environments are quite robust against several active attacks, for example, message stream modification attacks and chosen‐plain‐text attacks, and at the same time, they can also be useful to deal with some other issues like ‘limited error propagation’ existing in several conventional stream cipher modes like CFB, OFB, and CTR. Copyright © 2015 John Wiley & Sons, Ltd.

Lee and Yeh recently presented a delegation-based authentication protocol for portable communication systems (PCSs), which is claimed to provide non-repudiation in on-line authentication. This investigation indicates that their protocol has a weakness in that a malicious visited location register can forge the authentication messages in off-line authentication processes, preventing mobile users from obtaining non-repudiation in such processes. This study also presents an enhanced protocol, which not only has the same security properties as the original protocol but also avoids the weakness in the original scheme and reduces the computational cost.

Public discussion is a useful way for quantum key distribution protocols to reveal the presence of eavesdroppers. However, to ensure better security, nearly 50% of the transmitted qubits are spent in public discussions. Consequently, the original EPR quantum key distribution protocol provides only 25% qubit efficiency and Deng et al.'s scheme delivers only 50% qubit efficiency. By bringing classical cryptographic techniques into the quantum arena, this work proposes EPR quantum key distribution protocols with a potential of 100% qubit efficiency.

Public-key certificates, which are used to associate public keys with certificate owner identifiers, play an important role in public-key infrastructures. Each public-key certificate must be revoked as soon as its corresponding private key is compromised, lost or invalid. Before a public key is used, its associated public-key certificate must therefore be verified to ensure that it has not been revoked. However, the revocation and revocation notification of public keys are sometimes costly in terms of communication and computation requirements. A new unimplemented public-key encryption is proposed, which allows a user to update his private key without changing the corresponding public key, so that public-key revocation and revocation verification are not needed. In addition, the proposed scheme provides the following benefits: (1) prompt disabling of decryption capability (users' decryption ability can be revoked in real time); (2) personal key privacy (users select their partial private key without exposing it to certificate authorities) and (3) chosen-ciphertext security (the proposed scheme is provably secure against adaptive chosen-ciphertext attacks, in the random oracle model).

This work presents quantum key distribution protocols (QKDPs) to safeguard security in large networks, ushering in new directions in classical cryptography and quantum cryptography. Two three-party QKDPs, one with implicit user authentication and the other with explicit mutual authentication, are proposed to demonstrate the merits of the new combination, which include the following: 1) security against such attacks as man-in-the-middle, eavesdropping and replay; 2) efficiency is improved as the proposed protocols contain the fewest number of communication rounds among existing QKDPs; and 3) two parties can share and use a long-term secret (repeatedly). To prove the security of the proposed schemes, this work also presents a new primitive called the unbiased-chosen basis (UCB) assumption

For original paper see Hwang and Ku (IEEE Trans. Commun., vol.43, p.1947-9, 1995 May). The present authors find that the key distribution protocol KDP2 proposed in the original paper is, in fact, not reparable, as was claimed by the original authors. A reparable revised version of this KPD2 is then introduced. In a reply Hwang presents an example to show that the Lin et al. revised reparable KDP2 did not solve the problem which they proposed.

A (t,n) threshold signature scheme allows n members of a group to share a secret key such that any t members can create a valid group signature. Of course, any t members can compromise this system. However designing a (t,n) threshold signature scheme based on the Digital Signature Standard (DSS) is difficult if there is no trusted party to distribute the shares of the secret. Langford (1995) proposed a (t/sup 2/-t+1)-out-of-n threshold DSS signature scheme without a trusted party. It requires t/sup 2/-t+1 members to sign a document, but t members can conspire to destroy this scheme. Gennaro et al. (1996) improved that result by proposing a robust threshold DSS signature scheme which requires 2t+1 members in the signing procedure. This paper proposes a new method to reduce the number of signers to t+1. We also extend our scheme to a generalized case.

Park et al. (see Proceedings of EuroCrypto '93, p.T131, 1993) previously proposed an efficient key distribution scheme for digital mobile communications. Two attacks are given in this paper to show that their scheme is not secure enough for session key distributions. A modified protocol is proposed to avoid these weaknesses.

A new concept of reparable key distribution protocol is introduced in this paper. The merit of a reparable protocol is in that once all compromised keys have been replaced by secure keys, the protocol is secure. We show that the key distribution protocol of Lu et al. (1989), for Internet is not reparable. A reparable one is proposed instead.>