Pub. online:6 May 2020Type:Research ArticleOpen Access
Journal:Informatica
Volume 31, Issue 2 (2020), pp. 277–298
Abstract
The vulnerable part of communications between user and server is the poor authentication level at the user’s side. For example, in e-banking systems for user authentication are used passwords that can be lost or swindled by a person maliciously impersonating bank.
To increase the security of e-banking system users should be supplied by the elements of public key infrastructure (PKI) but not necessary to the extent of standard requirements which are too complicated for ordinary users.
In this paper, we propose two versions of authenticated key agreement protocol (AKAP) which can be simply realized on the user’s side. AKAP is a collection of cryptographic functions having provable security properties.
It is proved that AKAP1 is secure against active adversary under discrete logarithm assumption when formulated certain conditions hold. AKAP2 provides user’s anonymity against eavesdropping adversary. The partial security of AKAP2 is investigated which relies on the security of asymmetric encryption function.
Enhanced Matrix Power Function for Cryptographic Primitive Construction
Pub. online:17 Nov 2025Type:Research ArticleOpen Access
Journal:Informatica
Volume 36, Issue 4 (2025), pp. 1013–1035
Abstract
In this paper, we present an enhanced version of a previously published symmetric block cipher implemented for the encryption of digital images. We introduce an additional step of using Arnold’s cat map prior to encryption to improve its quality. After inspecting the statistical characteristics of the ciphertexts for the electronic codebook (ECB) and cipher block chaining (CBC) modes, we found that with this additional step, our schemes produce high entropy ciphertexts for both regular and monochromatic images. Therefore, the results obtained in this paper show that our schemes are indifferent to the Advanced Encryption Standard (AES) cipher. Moreover, due to an effective parallelization of matrix operations, we think that our proposal can be executed reasonably fast.
Improved Asymmetric Cipher Based on Matrix Power Function with Provable Security
Eligijus Sakalauskas, Aleksejus Mihalkovich, Algimantas Venčkauskas