Pub. online:6 Mar 2024Type:Research ArticleOpen Access
Journal:Informatica
Volume 35, Issue 1 (2024), pp. 131–154
Abstract
Signcryption integrates both signature and encryption schemes into single scheme to ensure both content unforgeability (authentication) and message confidentiality while reducing computational complexity. Typically, both signers (senders) and decrypters (receivers) in a signcryption scheme belong to the same public-key systems. When signers and decrypters in a signcryption scheme belong to heterogeneous public-key systems, this scheme is called a hybrid signcryption scheme which provides more elastic usage than typical signcryption schemes. In recent years, a new kind of attack, named side-channel attack, allows adversaries to learn a portion of the secret keys used in cryptographic algorithms. To resist such an attack, leakage-resilient cryptography has been widely discussed and studied while a large number of leakage-resilient schemes have been proposed. Also, numerous hybrid signcryption schemes under heterogeneous public-key systems were proposed, but none of them possesses leakage-resilient property. In this paper, we propose the first hybrid signcryption scheme with leakage resilience, called leakage-resilient hybrid signcryption scheme, in heterogeneous public-key systems (LR-HSC-HPKS). Security proofs are demonstrated to show that the proposed scheme provides both authentication and confidentiality against two types of adversaries in heterogeneous public-key systems.
Pub. online:19 Dec 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 34, Issue 1 (2023), pp. 199–222
Abstract
Due to the popularity of mobile communication, many computing devices are exposed to remote environments without physical protection so that these devices easily suffer from leakage attacks (e.g., side-channel attacks). Under such leakage attacks, when a computing device performs some cryptographic algorithm, an adversary may acquire partial bits of secret keys participated in this cryptographic algorithm. To resist leakage attacks, researchers offer leakage-resilient cryptography as a solution. A signcryption scheme combines signing and encrypting processes to simultaneously provide both authentication and confidentiality, which is an important cryptographic primitive. Indeed, many leakage-resilient signcryption schemes under various public key system (PKS) settings were proposed. Unfortunately, these schemes still have two shortcomings, namely, bounded leakage resilience and conditionally continuous leakage resilience. In this paper, a “fully” continuous leakage-resilient certificate-based signcryption (FCLR-CBSC) scheme is proposed. Security analysis is formally proved to show that our scheme possesses both authentication and confidentiality against two types of adversaries in the certificate-based PKS setting. Performance analysis and simulation experience show that our scheme is suited to run on both a PC and a mobile device.
Journal:Informatica
Volume 23, Issue 1 (2012), pp. 27–45
Abstract
Key-insulated cryptography is an important technique to protect private keys in identity-based (IB) cryptosytems. Despite the flurry of recent results on IB key-insulated encryption (IBKIE) and signature (IBKIS), a problem regarding the security and efficiency of practicing IBKIE and IBKIS as a joint IB key-insulated signature/encryption scheme with a common set of parameters and keys remains open. To deal with the above question, we propose an identity-based key-insulated signcryption (IBKISC) scheme. Compared with the Sign-then-Encrypt (StE) and Encrypt-then-Sign (EtS) using IBKIE and IBKIS in the standard model, our proposed IBKISC scheme is the fastest with the shortest ciphertext size.
Journal:Informatica
Volume 18, Issue 1 (2007), pp. 125–136
Abstract
A key exchange (or agreement) protocol is designed to allow two entities establishing a session key to encrypt the communication data over an open network. In 1990, Gunther proposed an identity-based key exchange protocol based on the difficulty of computing a discrete logarithm problem. Afterwards, several improved protocols were proposed to reduce the number of communication steps and the communicational cost required by Gunther's protocol. This paper presents an efficient identity-based key exchange protocol based on the difficulty of computing a discrete logarithm problem. As compared with the previously proposed protocols, it has better performance in terms of the computational cost and the communication steps. The proposed key exchange protocol provides implicit key authentication as well as the desired security attributes of an authenticated key exchange protocol.
Journal:Informatica
Volume 14, Issue 3 (2003), pp. 289–294
Abstract
Smart card has been adopted to various applications. In 2000, Hwang and Li proposed a remote user authentication scheme, which is also using smart card. Nine months later, Chan and Cheng pointed out that there is a weakness in the remote authentication scheme proposed by Hwang and Li. In this paper, we show that Chan and Cheng's attack does not work well because they did not consider the format of user's identity. In addition, we propose several ways to solve the problem of Chan and Cheng's attack.