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(Non-)Random Sequences from (Non-)Random Permutations—Analysis of RC4 Stream Cipher

Sourav Sen Gupta, Subhamoy Maitra, Goutam Paul, Santanu Sarkar
2012 Journal of Cryptology  
We also investigate for long-term non-randomness in the keystream, and prove a new long-term bias of RC4.  ...  Its internal state contains a permutation over all possible bytes from 0 to 255, and it attempts to generate a pseudorandom sequence of bytes (called keystream) by extracting elements of this permutation  ...  The target of an attack may be to exploit the non-randomness in the internal state of RC4, or the non-randomness of byte-extraction from the internal permutation.  ... 
doi:10.1007/s00145-012-9138-1 fatcat:jc6baa44djbi7ojqsmtxpypr3q

Further non-randomness in RC4, RC4A and VMPC

Santanu Sarkar
2014 Cryptography and Communications  
Naturally, these biases provide new distinguishers for the psedo-random keystream generated from these algorithms. In particular, our result provides the strongest distinguisher against VMPC.  ...  In this paper we identify several new biases for RC4, RC4A and VMPC, which are designed in similar paradigm.  ...  This bias arises from the non-random byte-extraction routine of RC4 PRGA. The bias produces a distinguisher of complexity O(N ) for RC4. In SAC 2010, Sepehrdad et al.  ... 
doi:10.1007/s12095-014-0119-0 fatcat:vk4ysedg5ra5jd7vd5nm5nvtpu

Analysis of Non-fortuitous Predictive States of the RC4 Keystream Generator [chapter]

Souradyuti Paul, Bart Preneel
2003 Lecture Notes in Computer Science  
This paper proposes an efficient algorithm to compute a special set of RC4 states named non-fortuitous predictive states.  ...  The RC4 stream cipher is the most widely used software based stream cipher. It is based on a secret internal state of N = 256 bytes and two pointers.  ...  The second part is the output generation part PRGA which produces pseudo-random bytes using the permutation derived from KSA. Each iteration or 'round' produces one output value.  ... 
doi:10.1007/978-3-540-24582-7_4 fatcat:hv5wesatfzb6ddoa3frlidmtye

RC4-2S: RC4 Stream Cipher with Two State Tables [chapter]

Maytham M. Hammood, Kenji Yoshigoe, Ali M. Sagheer
2013 Lecture Notes in Electrical Engineering  
The experimental results confirm that the output streams generated by the RC4-2S are more random than that generated by RC4 while requiring less time than RC4.  ...  RC4-2S stream cipher system solves the correlation problem between the public known outputs of the internal state using permutation between state 1 (S 1 ) and state 2 (S 2 ).  ...  The SUCCESS indicates the sequence is acceptable and has good randomness, where the FAILURE mean the sequence is not acceptable due to non-randomness.  ... 
doi:10.1007/978-94-007-6996-0_2 fatcat:suh4eixqt5fqdoh3rbf6nd37z4

RC4-Hash: A New Hash Function Based on RC4 [chapter]

Donghoon Chang, Kishan Chand Gupta, Mridul Nandi
2006 Lecture Notes in Computer Science  
In this paper, we propose a new hash function based on RC4 and we call it RC4-Hash. This proposed hash function produces variable length hash output from 16 bytes to 64 bytes.  ...  To the best of our knowledge, the design criteria of our hash function is different from all previously known hash functions.  ...  Pinakpani Pal for helping us in software implementation for checking the performance of RC4-Hash.  ... 
doi:10.1007/11941378_7 fatcat:wg5u3lrxsnhjdbwn6gittiwm7y

Randomized Stopping Times and Provably Secure Pseudorandom Permutation Generators [chapter]

Michal Kulis, Pawel Lorek, Filip Zagorski
2017 Lecture Notes in Computer Science  
We suggest a different approach by utilization of randomized stopping rules to generate permutations which are indistinguishable from uniform ones.  ...  Nevertheless, both cases require O(n log 2 n) bits of randomness while one can replace the shuffle used in RC4 (and in Spritz) with a better shuffle which is optimal and needs only O(n log n) bits.  ...  PRGA (Pseudo Random Generation Algorithm) starts with a permutation generated by KSA and outputs random bits from it updating permutation at the same time.  ... 
doi:10.1007/978-3-319-61273-7_8 fatcat:kboqv6urs5alri6kfkp57cfjlq

RC4 Encryption-A Literature Survey

Poonam Jindal, Brahmjit Singh
2015 Procedia Computer Science  
The attraction of community towards RC4 is still alive.  ...  These flaws in RC4 are still offering an open challenge for developers.  ...  non-random events.  ... 
doi:10.1016/j.procs.2015.02.129 fatcat:3eheztbbh5hwtp6al2am74zq34

Enhancing Security and Speed of RC4

Maytham M. Hammood et. al.
2015 International Journal of Computing and Network Technology  
In this paper, we propose RC4 stream cipher with a random initial state (RRC4) to solve the weak keys problem of the RC4 using a random initialization of internal state S.  ...  We also propose RC4 stream cipher with two state tables (RC4-2S) to solve the correlation problem between the public known outputs of the internal state using permutation between state1 (S 1 ) and state  ...  Mironov [16] presented a new model of RC4 and analyzed it by applying the theory of the random permutation.  ... 
doi:10.12785/ijcnt/030201 fatcat:nxesce4z6vabrcx5kvxixohgna

A Practical Attack on Broadcast RC4 [chapter]

Itsik Mantin, Adi Shamir
2002 Lecture Notes in Computer Science  
In this paper we describe a major statistical weakness in RC4, which makes it trivial to distinguish between short outputs of RC4 and random strings by analyzing their second bytes.  ...  RC4 is the most widely deployed stream cipher in software applications.  ...  Distinguishing RC4 from Random Sources. The best distinguisher mentioned in the literature ([FM00]), distinguishes RC4 from a random source by analyzing 2 30.6 output words.  ... 
doi:10.1007/3-540-45473-x_13 fatcat:bwrycl555rbfdk7ujnrzwibvve

A Survey on RC4 Stream Cipher

Poonam Jindal, Brahmjit Singh
2015 International Journal of Computer Network and Information Security  
In this paper we have presented a chronological survey of RC4 stream cipher demonstrating its weaknesses followed by the various RC4 enhancements from the literature.  ...  From the recently observed cryptanalytic attempts on RC4 it is established that innovative research efforts are required to develop secure RC4 algorithm, which can remove the weaknesses of RC4, such as  ...  non-random events.  ... 
doi:10.5815/ijcnis.2015.07.05 fatcat:qksutfja6behxmg7ycsq3fea3e

Weaknesses in the Key Scheduling Algorithm of RC4 [chapter]

Scott Fluhrer, Itsik Mantin, Adi Shamir
2001 Lecture Notes in Computer Science  
We identify a large number of weak keys, in which knowledge of a small number of key bits suffices to determine many state and output bits with non-negligible probability.  ...  In this paper we present several weaknesses in the key scheduling algorithm of RC4, and describe their cryptanalytic significance.  ...  Let p be the probability of a random key to be special 2-exact. Then C can be distinguished from a random stream by analyzing the first few words of about 200 p 2 different RC4 streams.  ... 
doi:10.1007/3-540-45537-x_1 fatcat:xltzf6dnqffzlnpqkynf5y56fa

(Not So) Random Shuffles of RC4 [chapter]

Ilya Mironov
2002 Lecture Notes in Computer Science  
To this end we propose an idealized model of RC4 and analyze it applying the theory of random shuffles. Based on our analysis of the model we recommend dumping at least 512 bytes.  ...  Most guidelines for implementation of the RC4 stream cipher recommend discarding the first 256 bytes of its output.  ...  Random Shuffles in RC4 In this section we describe our idealized model for RC4. We model KeySched and PseudoRand as a random shuffle and study the resulting distribution of the permutation S.  ... 
doi:10.1007/3-540-45708-9_20 fatcat:77hxtagebnhy5hqzf46jv7unp4

Towards a General RC4-Like Keystream Generator [chapter]

Guang Gong, Kishan Chand Gupta, Martin Hell, Yassir Nawaz
2005 Lecture Notes in Computer Science  
Today, most processors use 32-bit or 64bit words but using original RC4 with 32/64 bits is infeasible due to the large memory constraints and the number of operations in the key scheduling algorithm.  ...  RC4 was designed in 1987 when 8-bit and 16-bit processors were commercially available.  ...  A secret key K is then used to initialize S to a random permutation by shuffling the words in S. During the second phase of the operation, the PRGA produces random words from the permutation in S.  ... 
doi:10.1007/11599548_14 fatcat:6siiumd6vbgsjfzls45ew6h7oi

A New Variant Of Rc4 Stream Cipher

Lae Lae Khine
2009 Zenodo  
In this paper, we proposed a new variant of RC4 stream cipher.  ...  RC4 was used as an encryption algorithm in WEP(Wired Equivalent Privacy) protocol that is a standardized for 802.11 wireless network.  ...  RC4 consists of two parts, a key scheduling algorithm (KSA) which turns a random key (whose typical size is 40−256 bits) into an initial permutation of S-box of } 1 ..... 0 { − N , where N is a power of  ... 
doi:10.5281/zenodo.1071019 fatcat:q4h3ez62bvg77lkumgezngi7ra

RC4 Stream Cipher with a Random Initial State [chapter]

Maytham M. Hammood, Kenji Yoshigoe, Ali M. Sagheer
2013 Lecture Notes in Electrical Engineering  
RRC4 solves the weak keys problem of the RC4 using random initialization of internal state S.  ...  Experimental results show that the output streams generated by RRC4 are more random than that generated by RC4.  ...  Mironov [11] presented a new model of RC4 and analyzed it by applying the theory of random permutation.  ... 
doi:10.1007/978-94-007-6996-0_42 fatcat:uehxe4s3svfrhkc22g377kigou
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