Security proofs for an efficient password-based key exchange

Computational Indistinguishability Logic (CIL) is a logic for reasoning about cryptographic primitives in computational model. It is sound for standard model, but also supports reasoning in the random oracle and other idealized models. We illustrate the benefits of CIL by formally proving the security of a Password-Based Key Exchange (PBKE) scheme, which is designed to provide entities communicating over a public network and sharing a short password, under a session key.

After going through past research, it is observed that the security of data depends on five important key features such as authentication, data Integrity, mutual authentication between two parties, non-repudiation, and key exchange algorithm. Even if one of these features fail then it may breach security in real-world scenarios. The Diffie-Hellman Key Exchange (DHKE) algorithm allows securing one feature called key exchange in the cryptography field. However, this key exchange algorithm is unable to provide authentication. As a result, this key exchange scheme is prone to a hostile attack named as Man-In-The-Middle Attack (MITM). To solve this type of attack, a novel algorithm has been proposed called modification of the DHKE algorithm. In this algorithm, they claim that the MITM attack on classical DHKE can be prevented by applying the necessary functionalities like encryption and Zero-Knowledge Proof (ZKP). Although, after going through result analysis and working techniques, it is observed that the modified DHKE algorithm is still suffering from MITM attack. In this paper, the main objective is to develop an algorithm for finding out this type of security flaw in the existing modified DH algorithm which includes the concept of required authentication and encryption functions and able to perform the MITM attack on the existing modified DHKE algorithm.

In smart grid, key exchange protocols play a vital role in providing secure channels to read consumption reports from the smart meters. Thus far, several key exchange schemes have been proposed for the networked smart meters. However, for the first time, quite recently, Sha et al . have presented an interesting two-phase authentication and key agreement scheme that exclusively aims at the isolated smart meters. In their scheme, they have properly addressed the computationally constrained smart meters by offering a lightweight key exchange protocol. Nevertheless, after meticulous observation, we found that their proposed scheme cannot resist the desynchronization attack and cannot provide the perfect forward secrecy. Moreover, there are some other weaknesses in their scheme. As a result, to tackle the existing security challenges, in this paper, by utilization of the extended Chebyshev chaotic maps, we propose an efficient anonymous password-authenticated key exchange protocol that not only is free from the limitations of Sha et al .'s scheme, but also provides the anonymity. The security analysis in the random oracle model and using the widely accepted ProVerif tool besides the computational and communication costs comparison demonstrate that the proposed scheme has reached a proper level of efficiency without sacrificing the desired security properties.

Abstract—Modular design is a common approach for dealing with complex tasks in modern cryptology. The critical of this approach is that designing a secure hybrid protocol. In this paper, we study password-based key exchange in the three-party setting within the UC framework and design a hybrid protocol that UC-securely realizes such task. That is, we firstly define an appropriate ideal functionality F3-pwKE for password-based three-party key exchange. Next we partition the task into two sub-tasks, three-party key distribution and password-based two-party key exchange, and propose relevant two ideal functionalities, F3-KD, FpwKE. Finally, we present a (F3-KD, FpwKE)-hybrid protocol for password-based three-party key exchange that is proved to be UC-secure with respect to non- adaptive party corruption.

With a trusted-third-party (TTP)-based key exchange protocol, when a user would like to transmit a message to another user, the transmitted data are encrypted by a session key exchanged between the two ends of the corresponding connection with the help of the TTP. Up to present, due to the assistance of a TTP, this type of protocols has performed well in protecting messages delivered between two authorized users. Even this, inflexibility, unreliability, and inefficiency problems still exist in these previously proposed protocols. Therefore, in this paper, a multi-key exchange protocol, named the TTP-based high-efficient multi-key exchange protocol (THMEP), is proposed to provide users with a secure and efficient protocol, which employs the elliptic curve cryptography, a 2-D operation, and a current time encryption key, to exchange their session keys. The proposed protocol not only effectively hides important encryption parameters, but also achieves fully mutual authentication between a user and his/her trusted server. It can resist known-key, impersonation, replay, eavesdropping, and forgery attacks. Besides, the THMEP generates 40 session keys in a key exchange process, meaning the proposed protocol can support 40 sessions simultaneously. It also shortens the processing time, which is 3.78 times faster than that of a specific previous study. Its security level and performance are higher than those of the compared state-of-the-art protocols. In other words, the THMEP is very suitable for IoT applications.

키 교환 프로토콜은 공개 네트워크상에서 안전한 통신 채널을 구축하는데 필수적인 요소이다. 특히, 패스워드 기반 키 교환 프로토콜에서는 패스워드를 이용하여 사용자 인증이 이루어지며 이를 바탕으로 안전하게 키 교환이 이루어지도록 설계되어야 한다. 그러나 패스워드는 인간이 쉽게 기억할 수 있는 반면에 엔트로피가 낮고 따라서 사전공격에 쉽게 노출될 수 있다. 최근, Zhao와 Gu가 서버의 도움을 필요로 하는 새로운 패스워드 기반 키 교환 프로토콜을 제안하였다. Zhao와 Gu가 제안한 프로토콜은 일회성 비밀키의 노출 상황을 고려하는 공격자 모델에서도 안전성이 증명가능하다고 주장하였다. 본 논문에서는 Zhao와 Gu의 프로토콜에 대한 재전송 공격을 통하여 이 프로토콜이 저자들의 주장과 달리 일회성 비밀키의 노출 시에 안전하지 않다는 것을 보일 것이다. 본 연구 결과는 Zhao와 Gu가 제시한 안전성 증명이 성립하지 않음을 의미한다.

A secure and efficient AKE scheme for IoT devices using PUF and cancellable biometrics

This paper proposes a password-based authentication protocol suitable to certification through trustless network or key exchange. While the existing password-base protocols certify users through certification authority (CA) between client and server, in the proposed protocol of this paper, the users and the server exchange keys and perform authentication without the help of CA. To ameliorate the drawback of password-based protocols caused by the short length and randomness of password, the proposed protocol uses the signature techniques of ECDSA and the SRP protocol based on Diffie-Hellman key exchange method.

Proposed paper gives a secure key exchange scheme using block upper triangular matrices of higher order. By using this method it is possible to generate keys of large orders without the need of large primes thereby avoiding the common ciphertext attacks. The element used for generating shared key is the element of (1, 3) block of the matrix which depends upon the elements of (1, 2) as well as on the (2, 3) blocks thereby increasing the hardness of the problem and providing greater security. Moreover our proposal is compared with the method proposed by Alvarez et al. (2009) Key words: Block upper triangular matrices, public key cryptography, polynomial matrices, DH key exchange.

SUMMARYIn this paper, we first showed that Lou and Huang's three‐party password‐based key exchange protocol is still vulnerable to offline dictionary attacks. Thereafter, we proposed an enhanced protocol that can defeat the attack described and yet is efficient. Finally, we provided the rigorous proof of the security for it. Copyright © 2011 John Wiley & Sons, Ltd.

Supersingular Isogeny Diffie-Hellman (SIDH) is a key exchange scheme that is believed to be quantum-resistant. It is based on the difficulty of finding a certain isogeny between given elliptic curves. Over the last nine years, optimizations have been proposed that significantly increased the performance of its implementations. Today, SIDH is a promising candidate in the US National Institute for Standards and Technology’s (NIST’s) post-quantum cryptography standardization process. This work is a self-contained introduction to the active research on SIDH from a high-level, algorithmic lens. After an introduction to elliptic curves and SIDH itself, we describe the mathematical and algorithmic building blocks of the fastest known implementations. Regarding elliptic curves, we describe which algorithms, data structures and trade-offs regard- ing elliptic curve arithmetic and isogeny computations exist and quantify their runtime cost in field operations. These findings are then tailored to the situation of SIDH. As a result, we give efficient algorithms for the performance-critical parts of the protocol.

Security is a significant problem for communications in many scenarios in Internet of Things (IoT), such as military applications, electronic payment, wireless reprogramming of smart devices and so on. To protect communications, a secret key shared by the communicating parties is often required. Authenticated key exchange (AKE) is one of the most widely used methods to provide two or more parties communicating over an open network with a shared secret key. It has been studied for many years. A large number of protocols are available by now. The majority of existing AKE protocols require the two communicating parties execute equivalent computational tasks. However, many communications take place between two devices with significantly different computational capabilities, such as a cloud center and a mobile terminal, a gateway and a sensor node, and so on. Most available AKE protocols do not perfectly match these scenarios. To further address the security problem in communications between parties with fairly unbalanced computational capabilities, this thesis studies AKE protocols with unbalanced computational requirements on the communicating parties. We firstly propose a method to unbalance computations in the Elliptic Curve Diffie-Hellman (ECDH) key exchange scheme. The resulting scheme is named as UECDH scheme. The method transfers one scalar multiplication from the computationally limited party to its more powerful communicating partner. It significantly reduces the computational burden on the limited party since scalar multiplication is the most time-consuming operation in the ECDH scheme. When applying the UECDH scheme to design AKE protocols, the biggest challenge is how to achieve authentication. Without authentication, two attacks (the man-in-the-middle attack and the impersonation attack) can be launched to the protocols. To achieve authentication, we introduce different measures that are suitable for a variety of use cases. Based on the authentication measures, we propose four suites of UECDH-based AKE protocols. The security of the protocols is discussed in detail. We also implement prototypes of these protocols and similar protocols in international standards including IEEE 802.15.6, Transport Layer Security (TLS) 1.3 and Bluetooth 5.0. Experiments are carried out to evaluate the performance. The results show that in the same experimental platform, the proposed protocols are more friendly to the party with limited computational capability, and have better performance than similar protocols in these international standards.

In three-party password authenticated key exchange (AKE) protocol, since two users use their passwords to establish a secure session key over an insecure communication channel with the help of the trusted server, such a protocol may suffer the password guessing attacks and the server has to maintain the password table. To eliminate the shortages of password-based AKE protocol, very recently, according to chaotic maps, Lee et al. [2015 Nonlinear Dyn. 79 2485] proposed a first three-party-authenticated key exchange scheme without using passwords, and claimed its security by providing a well-organized BAN logic test. Unfortunately, their protocol cannot resist impersonation attack, which is demonstrated in the present paper. To overcome their security weakness, by using chaotic maps, we propose a biometrics-based anonymous three-party AKE protocol with the same advantages. Further, we use the pi calculus-based formal verification tool ProVerif to show that our AKE protocol achieves authentication, security and anonymity, and an acceptable efficiency.

Based on mobile devices limitations, several user authentications and key exchange schemes have been proposed for mobile devices using identity-based public key cryptography (ID-PKC). However, these schemes suffer from key escrow problem. Moreover, they are not secure against impersonation attacks, and they can’t achieve perfect forward secrecy. In this paper, a new user authentication and key exchange protocol for the mobile client-server environment is proposed. Certificateless public key cryptography (CL-PKC) and bilinear pairing are adopted in the proposed scheme. Our protocol solves the key escrow problem of identity-based public key cryptography. Also, it is secure against both adversaries type I and type II. Furthermore, the proposed protocol achieves perfect forward secrecy. We prove the security of our protocol in the random oracle model under the Computational Diffie-Hellman (CDH) problem. Hence, the proposed scheme is more suitable for the mobile devices environments.

Complex-valued hyperchaos-assisted vector-valued artificial neural key coordination for improving security in the Industrial Internet of Things