577 research outputs found

    New CBC-MAC forgery attacks

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    Using Simon's Algorithm to Attack Symmetric-Key Cryptographic Primitives

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    We present new connections between quantum information and the field of classical cryptography. In particular, we provide examples where Simon's algorithm can be used to show insecurity of commonly used cryptographic symmetric-key primitives. Specifically, these examples consist of a quantum distinguisher for the 3-round Feistel network and a forgery attack on CBC-MAC which forges a tag for a chosen-prefix message querying only other messages (of the same length). We assume that an adversary has quantum-oracle access to the respective classical primitives. Similar results have been achieved recently in independent work by Kaplan et al. Our findings shed new light on the post-quantum security of cryptographic schemes and underline that classical security proofs of cryptographic constructions need to be revisited in light of quantum attackers.Comment: 14 pages, 2 figures. v3: final polished version, more formal definitions adde

    On the security of XCBC, TMAC and OMAC

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    The security provided by the XCBC, TMAC and OMAC schemes is analysed and compared with other MAC schemes. The results imply that there is relatively little to be gained practically through the introduction of these schemes by comparison with other well-established MAC functions. Moreover, TMAC and OMAC possess design weaknesses which enable part of the secret key to be recovered much more easily than would ideally be the case — design changes are suggested which alleviate this problem. Whether or not the proofs of security are retrievable for the modified designs remains an open question, although the need for change would appear to be clear

    SOFIA : software and control flow integrity architecture

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    Microprocessors used in safety-critical systems are extremely sensitive to software vulnerabilities, as their failure can lead to injury, damage to equipment, or environmental catastrophe. This paper proposes a hardware-based security architecture for microprocessors used in safety-critical systems. The proposed architecture provides protection against code injection and code reuse attacks. It has mechanisms to protect software integrity, perform control flow integrity, prevent execution of tampered code, and enforce copyright protection. We are the first to propose a mechanism to enforce control flow integrity at the finest possible granularity. The proposed architectural features were added to the LEON3 open source soft microprocessor, and were evaluated on an FPGA running a software benchmark. The results show that the hardware area is 28.2% larger and the clock is 84.6% slower, while the software benchmark has a cycle overhead of 13.7% and a total execution time overhead of 110% when compared to an unmodified processor

    Energy Efficient Security Framework for Wireless Local Area Networks

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    Wireless networks are susceptible to network attacks due to their inherentvulnerabilities. The radio signal used in wireless transmission canarbitrarily propagate through walls and windows; thus a wireless networkperimeter is not exactly known. This leads them to be more vulnerable toattacks such as eavesdropping, message interception and modifications comparedto wired-line networks. Security services have been used as countermeasures toprevent such attacks, but they are used at the expense of resources that arescarce especially, where wireless devices have a very limited power budget.Hence, there is a need to provide security services that are energy efficient.In this dissertation, we propose an energy efficient security framework. Theframework aims at providing security services that take into account energyconsumption. We suggest three approaches to reduce the energy consumption ofsecurity protocols: replacement of standard security protocol primitives thatconsume high energy while maintaining the same security level, modification ofstandard security protocols appropriately, and a totally new design ofsecurity protocol where energy efficiency is the main focus. From ourobservation and study, we hypothesize that a higher level of energy savings isachievable if security services are provided in an adjustable manner. Wepropose an example tunable security or TuneSec system, which allows areasonably fine-grained security tuning to provide security services at thewireless link level in an adjustable manner.We apply the framework to several standard security protocols in wirelesslocal area networks and also evaluate their energy consumption performance.The first and second methods show improvements of up to 70% and 57% inenergy consumption compared to plain standard security protocols,respectively. The standard protocols can only offer fixed-level securityservices, and the methods applied do not change the security level. The thirdmethod shows further improvement compared to fixed-level security by reducing(about 6% to 40%) the energy consumed. This amount of energy saving can bevaried depending on the configuration and security requirements

    Security and Authentication for 802.11 Wireless Networks

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    Wireless Networks is a very growing market. However, the security measures are not strong enough; the WEP security protocol is flawed. The 802.11 Task Group I is working on new security measures in order to strengthen the access control of users, the privacy and the integrity of data. We will describe the WEP flaws and the new security measures of 802.11 Task Group I. Finally, we will propose a new architecture to improve user identification for the wireless network of our department

    Misbehaviour metrics in WiMAX networks under attack

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    Much effort has been taken to make WiMAX a secure technology. Due to its broadcast nature, WiMAX is more susceptible to security threats than a wired network. In this paper, we give a general overview of the security architecture and possible attacks that a WiMAX network may face. For each type of attack the misbehaviour metrics that may vary under these attacks are listed. This work can be used to select an appropriate threshold for detecting attack and can be applied to future research on IDS

    Cryptographic Security of SSH Encryption Schemes

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    Universal Forgery with Birthday Paradox: Application to Blockcipher-based Message Authentication Codes and Authenticated Encryptions

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    An universal forgery attack means that for any given message MM, an adversary without the key can forge the corresponding Message Authentication Code (MAC) tag Ď„\tau, and the pair (M,Ď„)(M,\tau) can be verified with probability 1. For a idea MAC, the universal forgery attack should be infeasible to be implemented, whose complexity is believed to be min{(2n,2k)(2^n, 2^k)} queries in the classic setting, where nn is the tag length and kk is the key length of the MAC, respectively. In this paper, we launch a general universal forgery attack to some blockcipher-based MACs and authenticated encryptions (AEs) using birthday attack, whose complexity is about O(2n/2)O(2^{n/2}) queries in the classic setting. The attack shows that such MACs and AEs are totally insecure. However, this attack is not applicable in the quantum model, since no inclusion of period in the input messages is guaranteed. We also propose other generic universal forgery attacks using collision finding with structural input messages with complexity of O(2n/2)O(2^{n/2}), by birthday paradox in the classic setting. Since our attacks are based on the collision finding with fixed but unknown differences (or period), such attacks can also be implemented with only O(n)O(n) queries using \textit{Simon\u27s} algorithm in the quantum model, which shows that such MACs and AEs are completely broken in the quantum model. Our attacks can be applied to CBC-MAC, XCBC, EMAC, OMAC, CMAC, PC-MAC, MT-MAC, PMAC, PMAC with parity, LightMAC and some of their variants. Moreover, such attacks are also applicable to the authenticated encryptions of the third round of the CAESAR candidates: CLOC, SILC, AEZ, COLM (including COPA and ELmD) and Deoxys
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