Intrusion Detection System for AES Encripted Low-Power IoT Networks

The introduction of the IPv6 protocol solved the problem of providingaddresses to network devices. With the emergence of the Internetof Things (IoT), there was also the need to develop a protocolthat would assist in connecting low-power devices. The 6LoWPANprotocols were created for this purpose. However, such protocolsinherited the vulnerabilities and threats related to Denial of Service(DoS) attacks from the IPv4 and IPv6 protocols. In this paper, weprepare a network environment for low-power IoT devices usingCOOJA simulator and Contiki operating system to analyze theenergy consumption of devices. Besides, we propose an IntrusionDetection System (IDS) associated with the AES symmetric encryptionalgorithm for the detection of reflection DoS attacks. Thesymmetric encryption has proven to be an appropriate methoddue to low implementation overhead, not incurring in large powerconsumption, and keeping a high level of system security. The maincontributions of this paper are: (i) implementation of a reflectionattack algorithm for IoT devices; (ii) implementation of an intrusiondetection system using AES encryption; (iii) comparison ofthe power consumption in three distinct scenarios: normal messageexchange, the occurrence of a reflection attack, and runningIDS algorithm. Finally, the results presented show that the IDSwith symmetric cryptography meets the security requirements andrespects the energy limits of low-power sensors.

Improved Single-Key Attacks on 2-GOST

GOST, known as GOST-28147-89, was standardized as the Russian encryption standard in 1989. It is a lightweight-friendly cipher and suitable for the resource-constrained environments. However, due to the simplicity of GOST’s key schedule, it encountered reflection attack and fixed point attack. In order to resist such attacks, the designers of GOST proposed a modification of GOST, namely, 2-GOST. This new version changes the order of subkeys in the key schedule and uses concrete S-boxes in round function. But regarding single-key attacks on full-round 2-GOST, Ashur et al. proposed a reflection attack with data of 2 32 on a weak-key class of size 2 224 , as well as the fixed point attack and impossible reflection attack with data of 2 64 for all possible keys. Note that the attacks applicable for all possible keys need the entire plaintext space. In other words, these are codebook attacks. In this paper, we propose single-key attacks on 2-GOST with only about 2 32 data instead of codebook. Firstly, we apply 2-dimensional meet-in-the-middle attack combined with splice-cut technique on full-round 2-GOST. This attack is applicable for all possible keys, and its data complexity reduces from previous 2 64 to 2 32 . Besides that, we apply splice-cut meet-in-the-middle attack on 31-round 2-GOST with only data of 2 32 . In this attack, we only need 8 bytes of memory, which is negligible.

Cryptanalysis of GOST2

GOST 28147 is a 256-bit key 64-bit block cipher developed by the USSR, later adopted by the Russian government as a national standard. In 2010, GOST was suggested to be included in ISO/IEC 18033-3, but was rejected due to weaknesses found in its key schedule. In 2015, a new version of GOST was suggested with the purpose of mitigating such attacks. In this paper, we show that similar weaknesses exist in the new version as well. More specifically, we present a fixed-point attack on the full cipher with time complexity of 2237 encryptions. We also present a reflection attack with time complexity of 2192 for a key that is chosen from a class of 2224 weak keys. Finally, we discuss an impossible reflection attack which improves on exhaustive search by a factor of 2e, and several possible related-key attacks.