LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16- round related-key impossible differentials of LBlock, which are better than the 15-round related-key impos...LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16- round related-key impossible differentials of LBlock, which are better than the 15-round related-key impossible differentials used in the previous attack. Based on these 16-round related-key impossible differentials, we can attack 23 rounds of LBlock while the previous related-key impossible differential attacks could only work on 22-round LBlock. This makes our attack on LBlock the best attack in terms of the number of attacked rounds.展开更多
In this paper, we examine the security of reduced AES-192 and AES-256 against related-key rectangle attacks by exploiting the weakness in the AES key schedule. We find the following two new attacks： 9-round reduced A...In this paper, we examine the security of reduced AES-192 and AES-256 against related-key rectangle attacks by exploiting the weakness in the AES key schedule. We find the following two new attacks： 9-round reduced AES-192 with 4 related keys, and 10-round reduced AES-256 with 4 related keys. Our results show that related-key rectangle attack with 4 related keys on 9-round reduced AES-192 requires a data complexity of about 2^101 chosen plaintexts and a time complexity of about 2^174.8 encryptions, and moreover, related-key rectangle attack with 4 related keys on 10-round reduced AES-256 requires a data complexity of about 2^97.5 chosen plaintexts and a time complexity of about 2^254 encryptions. These attacks are the first known attacks on 9-round reduced AES-192 and 10-round reduced AES-256 with only 4 related keys. Furthermore, we give an improvement of the 10-round reduced AES-192 attack presented at FSE2007, which reduces both the data complexity and the time complexity.展开更多
The block cipher Threefish is the main component of Skein, which is based on ARX. Based on the efficient algorithms for calculating the differential of modular addition, we extend local collisions of Threefish-256 to ...The block cipher Threefish is the main component of Skein, which is based on ARX. Based on the efficient algorithms for calculating the differential of modular addition, we extend local collisions of Threefish-256 to more round by using related-key differential of addition in this paper. A related-key boomerang distinguish attack is proposed on 31-round Threefish-256 with a time complexity of 2^（234）.展开更多
基金supported by the National Basic Research 973 Program of China under Grant No.2013CB834205the National Natural Science Foundation of China under Grant Nos.61133013,61070244,and 61103237+1 种基金the Program for New Century Excellent Talents in University of China under Grant No.NCET-13-0350the Interdisciplinary Research Foundation of Shandong University of China under Grant No.2012JC018
文摘LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16- round related-key impossible differentials of LBlock, which are better than the 15-round related-key impossible differentials used in the previous attack. Based on these 16-round related-key impossible differentials, we can attack 23 rounds of LBlock while the previous related-key impossible differential attacks could only work on 22-round LBlock. This makes our attack on LBlock the best attack in terms of the number of attacked rounds.
基金Supported by the National Natural Science Foundation of China (Grant No. 60673072)the National Basic Research Program of China(Grant No. 2007CB311201)
文摘In this paper, we examine the security of reduced AES-192 and AES-256 against related-key rectangle attacks by exploiting the weakness in the AES key schedule. We find the following two new attacks： 9-round reduced AES-192 with 4 related keys, and 10-round reduced AES-256 with 4 related keys. Our results show that related-key rectangle attack with 4 related keys on 9-round reduced AES-192 requires a data complexity of about 2^101 chosen plaintexts and a time complexity of about 2^174.8 encryptions, and moreover, related-key rectangle attack with 4 related keys on 10-round reduced AES-256 requires a data complexity of about 2^97.5 chosen plaintexts and a time complexity of about 2^254 encryptions. These attacks are the first known attacks on 9-round reduced AES-192 and 10-round reduced AES-256 with only 4 related keys. Furthermore, we give an improvement of the 10-round reduced AES-192 attack presented at FSE2007, which reduces both the data complexity and the time complexity.
基金Supported by the National Natural Science Foundation of China(61100201)the Foundation for Distinguished Young Talents in Higher Education of Guangdong(LYM11053)
文摘The block cipher Threefish is the main component of Skein, which is based on ARX. Based on the efficient algorithms for calculating the differential of modular addition, we extend local collisions of Threefish-256 to more round by using related-key differential of addition in this paper. A related-key boomerang distinguish attack is proposed on 31-round Threefish-256 with a time complexity of 2^（234）.
