基于FPGA的分组密码安全性检测方法研究

发布时间：2018-06-09 12:40

本文选题：分组密码 + 立方测试　；参考：《桂林电子科技大学》2016年硕士论文

【摘要】：分组密码属于对称密码体制,是保护信息安全的重要手段之一。目前所使用的主流分组密码算法是否存在安全漏洞?如何找出分组密码算法的安全漏洞?这正是业界讨论的重点。FPGA(Field-Programmable Gate Array)作为现场可编程门阵列以其编程灵活、处理速度快、设计周期短、成本低、实时验证能力强等特点而被广泛应用于密码实现与分析。本文就主流的3个分组密码算法AES(Advanced Encryption Standards),SIMON和SPECK(美国轻量级加密标准)算法的安全性检测展开研究。主要成果如下:1.在AES算法的密钥中比特检测及分析方面:根据AES算法的密钥编排特点和轮函数结构,结合立方测试的基本思想,利用FPGA测试平台设计了一个AES-128的密钥中比特检测算法。分析结果表明:在立方变元取17维至24维时,3轮简化AES-128的输出位均能够捕获到密钥中比特,而对于4轮以上AES-128的任何输出位均无法捕获到密钥中比特。这进一步说明了,4轮以上AES-128密码算法具有稳固的密钥信息扩散及混淆性。2.在简化SIMON类密码算法的立方分析方面:分别利用立方攻击和立方测试的基本思想,结合FPGA高速测试平台对SIMON32/64算法进行了分析。结果表明:对于7轮SIMON32/64算法,通过立方攻击能够直接恢复48比特密钥,攻击的数据复杂度约为17.152个选择明文,时间复杂度约为17.712次加密;对于8轮SIMON32/64算法,能够直接恢复32比特密钥,并找到了关于另外6比特密钥的4个线性多项式,攻击的数据复杂度约为15.482个选择明文,时间复杂度约为28.002次加密。可见,立方攻击可对低轮SIMON32/64算法产生实质性的威胁。对于9轮的SIMON32/64算法,通过立方测试能够捕获到密钥中比特。这进一步说明了,SIMON32/64算法要达到完全的混淆和扩散必须要经过10轮以上的迭代操作。3.在SPECK类密码算法的低轮立方测试与分析方面:利用立方攻击,并结合二次测试的基本思想,基于FPGA高速测试平台对SPECK32/64算法进行了分析,结果表明:在选择明文攻击条件下,若算法简化到3轮,则可直接恢复17比特密钥,攻击的数据复杂度约为10.022个选择明文,时间复杂度约为47.002次加密。可见,SPECK32/64算法必须要经过4轮以上的迭代操作才能有效的抵抗结合二次检测立方攻击。若算法简化到5轮,6轮,通过立方测试均能够捕获到密钥中比特。这进一步说明了,SPECK32/64算法要达到完全混淆和扩散至少要进行7轮以上的迭代运算。
[Abstract]:Block cipher, which belongs to symmetric cryptosystem, is one of the important means to protect information security. Is there a security flaw in the mainstream block cipher algorithm currently used? How to find out the security hole of block cipher algorithm? This is the focus of discussion in the industry. As a field programmable gate array, FPGA Field-Programmable Gate Arrayis widely used in cryptographic implementation and analysis because of its characteristics of flexible programming, fast processing, short design cycle, low cost and strong real-time verification ability. In this paper, the security detection of three mainstream block cipher algorithms, AESN Advanced encryption Standard and speck (American lightweight encryption Standard), is studied. The main results are as follows: 1. In the aspect of key detection and analysis of AES algorithm: according to the characteristic of key arrangement and the structure of round function of AES algorithm and the basic idea of cubic test, a key detection algorithm of AES-128 is designed based on FPGA test platform. The analysis results show that the output bits of three rounds of simplified AES-128 can capture the bits in the key when the cubic variables are taken from 17 to 24 dimensions, but no bits in the key can be captured for any output bits of AES-128 in more than four rounds. This further shows that the AES-128 cryptosystem has stable key information diffusion and confusion. In the aspect of simplifying the cubic analysis of Simon class cipher algorithm, using the basic idea of cubic attack and cubic test, the SIMON32 / 64 algorithm is analyzed with FPGA high-speed test platform. The results show that for 7 rounds of SIMON 32 / 64 algorithm, 48 bits of key can be recovered directly by cubic attack, the data complexity of attack is about 17.152 selected plaintext, the time complexity is about 17.712 encryption, and for 8 rounds of SIMON32 / 64 algorithm, The 32-bit key can be recovered directly and four linear polynomials about the other 6-bit keys are found. The data complexity of the attack is about 15.482 selected plaintext and the time complexity is about 28.002 times. Thus, the cubic attack can pose a substantial threat to the low-wheel SIMON 32 / 64 algorithm. For 9 rounds of SIMON 32 / 64 algorithm, the bit in the key can be captured by cube test. This further shows that the SIMON 32 / 64 algorithm must go through more than 10 iterations to achieve complete confusion and diffusion. In the aspect of low wheel cubic testing and analysis of SPECK cipher algorithm: using cubic attack and combining the basic idea of secondary test, the SPECK32 / 64 algorithm is analyzed based on FPGA high speed test platform. The results show that: under the condition of selecting plaintext attack, If the algorithm is simplified to three rounds, the 17-bit key can be recovered directly. The data complexity of the attack is about 10.022 selected plaintext, and the time complexity is about 47.002 times. It can be seen that SPECK32 / 64 algorithm must go through more than four iterations in order to effectively resist the combined secondary detection cube attack. If the algorithm is simplified to 5 rounds and 6 rounds, the bits in the key can be captured through the cube test. This further shows that the SPECK32 / 64 algorithm needs at least seven iterations to achieve complete confusion and diffusion.
【学位授予单位】：桂林电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN918.4;TN791

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