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The MQV is an authenticated key agreement protocol which does not use any one-way hash functions in its block design, and it is standardized in (IEEE, ANSI, and ISO). However, its two-pass form cannot withstand an unknown key share attack. Krawczyk proposed a hashed version of MQV (HMQV) to overcome the attack on MQV, but HMQV is vulnerable to small subgroup attacks. LaMacchia et al presented a strong security definition for authenticated key exchange protocol as extended Canetti-Krawczyk (eCK) to catch new attacks from a strong adversary. Ustaoglu proposed a hashed ephemeral private key with static private key of HMQV (CMQV) to have a security proof in eCK. Sarr et al showed key compromise impersonation and man-in-the-middle attacks on HMQV under revealing a signature of Diffie-Hellman of public keys and proposed fully HMQV (FHMQV) and strengthen MQV (SMQV) to overcome those attacks. In this study, we show the known key security attack on the MQV protocol and its variants (MQV, HMQV, CMQV, FHMQV, eFHMQV and SMQV) protocols, if both ephemeral private keys and the ephemeral session key equation are revealed by an extremely adversary; the extremely adversary is able to obtain the shared static key between two-party participants. As consequence, we show the shared static-key compromise impersonation attack on the MQV protocol and its evolutions protocols. Moreover, we show that the MTI/A(0) key agreement protocol cannot withstand key compromise impersonation attacks against stronger adversary revelation attacks.

nowadays, the success of many online applications relays on keeping the data sent through the global network secure and far away from hackers. To carry out this task, the two communicating parties must exchange keys during their session. Some of the key exchange protocols are called key agreement protocols. The Elliptic Curve-Diffie Hellman (ECDH) is one of the most efficient algoiithms for securing data. The ECDH is more efficient than other traditional techniques such as Rivest-Shamir-Adleman (RSA) in terms of key size, computation and network bandwidth. The Authenticated Key Agreement (AKA) protocol is used for establishing a common session key between the two communicating parties. The common session key is used for subsequent cryptography goals. Most of the key agreement protocols (e.g. Menezes-Qu-Vanstone(MQV) family) generate one key per session therefore increasing the opportunities for guessing the session key. In this paper, we focus on developing an enhanced multiple sessions key which is based on ECDH. We propose an efficient and secure AKA protocol which is based on the ideas of the hashed MQV (HMQV), the YAK protocol as a robust key agreement based on public key authentication and multiple session keys. The proposed protocol generates multiple common keys per a session, where the generated common key depends on the static and ephemeral keys. Furthermore, the proposed protocol overcomes the attacks on the HMQV and YAK protocols and provides desirable security properties as compared with the relatedworks in this paper.

Nowadays, the rapid growth of Internet applications open the doors for people to communicate and do business around the world and thus saving time, efforts and money. However, the success of these applications is based on protecting the data from hackers. It is well known that preventing sensitive data from hackers while they are sent through the global network is a big challenge. There are many techniques used for securing data. Some of these techniques are based on encrypting a readable text into an unreadable text using mathematical operations, while other techniques are based on encrypting a readable text into an image (e.g., the Text-to-Image Encryption algorithm – TTIE) or into musical notes using an encryption key. The encryption key must be secure and should not be sent through the Internet.\ud \ud This paper proposes adding a new security level to the TTIE algorithm, and demonstrates how the encryption key produced by the TTIE algorithm is exchanged with the other party using the Diffie Hellman technique. Thus, this paper proposes a modified TTIE algorithm called the Diffie Hellman Text-to-Image Encryption algorithm (DHTTIE), and tests and analyses the proposed algorithm.

Authenticated key agreement protocols are a foundation for delivering an authenticated session key between the intended two-party participants from a set of parties over an insecure network. Wang et al proposed protocol ECKE-1N to overcome KCI-R attacks in ECKE-1 as an implicit authenticated key agreement protocol based on Diffie-Hellman elliptic curve. In this paper, we show that ECKE-1N is vulnerable to both leakage of ephemeral private keys and KCI-R attacks. We present an enhanced protocol EECKE-1N, which can withstand KCI-R attacks and revelations both of ephemeral keys. Furthermore, EECKE-1N can provide desirable security proprieties.

In NRSC24, Elkamchouchi et al. proposed a new approach for key controlled agreement to provide key control in the Pour public key distribution system. In NRSC25, they further proposed an efficient and confirmed protocol for authenticated key agreement to provide forward secrecy in their previously proposed protocol. This paper, however, will show that Pour’s protocol and Elkamchouchi et al.’s two protocols cannot withstand key compromise impersonation resilience, and man-in-the-middle attacks, and do not have perfect forward secrecy resilience. To eliminate the pointed out security leaks, we further propose a new two-pass authenticated key agreement with a key confirmation protocol. The proposed protocol has the following properties: (i) it is proved to be secure against above attacks and stronger adversary attacks, and provides the desirable security properties as a three-pass authenticated key agreement protocol. (ii) It can provide entity authentication and assurance for key reception in an ind...