Abstract—Authenticated Encryption (AE) is a technique combines both security and authenticity of data. This paper introduces two possible attacks over AEGIS AE algorithm, which are error propagation and tag changing attacks. The first attack is sending incorrect ciphertext for error propagation, that will results in incorrect decryption of all next ciphertexts then retransmission is done which leads to large time delay. The second attack is changing the sent authenticated tag that will result incorrect tag calculation at the receiver. Tag Generation functions dependent on XOR function (linear function) as in AEGIS make the encryption algorithms vulnerable to tag changing attack. In the introduced paper, the proposed solutions are done regarding two security mechanisms which are tag partitioning and check tag resulted from nonlinear function. Tag partitioning is a process to divide the tag into parts this will reduce the time delay of retransmission and non-linear function usage to overcome XOR function problems.
Index Terms—AEGIS, AE, check tag, tag authentication, tag generation, tag partitioning.
Ayman Yousry El-Hadary is with the Department of Electronics and Communication, Cairo, Egypt (e-mail: a.elhadary99@yahoo.co.uk). Mohamed Helmy Megahed is with the Communications Department of Canadian International College (CIC), Cairo, Egypt (e-mail: mmega080@uottawa.ca). Mohamed Hassan Abd ElAzeim is with the Department of Electronics and Communication of Arab Academy for Science Technology and Maritime Transport (AASTMT), Cairo, Egypt (e-mail: mhabdazeem@hotmail.com).
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Cite:Ayman Y. El-Hadary, Mohamed Helmy Megahed, and Mohamed H. Abd ElAzeem, "A Proposed Solutions to Two Possible Attacks over AEGIS Authenticated Encryption Algorithm," International Journal of Computer Theory and Engineering vol. 10, no. 6, pp. 185-189, 2018.
