scholarly journals Key recovery attack on Circulant UOV/Rainbow

JSIAM Letters ◽  
2019 ◽  
Vol 11 (0) ◽  
pp. 45-48 ◽  
Author(s):  
Yasufumi Hashimoto
Keyword(s):  
Key Recovery ◽  
Key Recovery Attack

scholarly journals Cryptanalysis of Loiss Stream Cipher-Revisited

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Lin Ding ◽  
Chenhui Jin ◽  
Jie Guan ◽  
Qiuyan Wang
Keyword(s):  
Time Complexity ◽  
Stream Cipher ◽  
Linear Equations ◽  
Data Complexity ◽  
Secret Key ◽  
Key Recovery ◽  
Systems Of Linear Equations ◽  
Key Recovery Attack ◽  
Better Than

Loiss is a novel byte-oriented stream cipher proposed in 2011. In this paper, based on solving systems of linear equations, we propose an improved Guess and Determine attack on Loiss with a time complexity of 2231and a data complexity of 268, which reduces the time complexity of the Guess and Determine attack proposed by the designers by a factor of 216. Furthermore, a related key chosenIVattack on a scaled-down version of Loiss is presented. The attack recovers the 128-bit secret key of the scaled-down Loiss with a time complexity of 280, requiring 264chosenIVs. The related key attack is minimal in the sense that it only requires one related key. The result shows that our key recovery attack on the scaled-down Loiss is much better than an exhaustive key search in the related key setting.

Cryptanalysis of Cramer-Shoup Like Cryptosystems Based on Index Exchangeable Family

2021 ◽  
pp. 1-19
Author(s):  
Jinhui liu ◽  
Yong Yu ◽  
Bo Yang ◽  
Jianwei Jia ◽  
Qiqi Lai
Keyword(s):  
Linear Equation ◽  
Linear Group ◽  
Personal Computer ◽  
Public Key ◽  
Encryption Scheme ◽  
Public Key Encryption ◽  
Key Recovery ◽  
Encryption And Decryption ◽  
Key Recovery Attack

The Cramer-Shoup (CS) like cryptosystem based on index exchangeable family (IEF) construction is a novel scheme introduced in Asiaccs 2016 by Li et al.. Its versatility was illustrated by building two public key encryption (PKE) schemes, a cramer-shoup encryption scheme based on IEFs, as well as an outsourcing technique based on non-abelian analog. However, the two schemes are not secure over the recommended linear group of Li et al. For them, we provide a new key-recovery attack by solving a linear equation respectively. Furthermore, we peel off complex encryption and decryption processes and propose more than three different attack methods. Finally, we give a corresponding example to illustrate the correctness of our attack methods. Our attack methods break an instance of claiming 80 bit security less than one minute under a personal computer.

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