Method of deciphering wired cipher in the same privacy

Abstract

The method of cracking the Wired Equivalent Privacy Class Cipher involves cracking a cryptographic protocol such as WEP based on the RC4 algorithm. This method uses the second output byte of PRGA to crack, that is, in the running process of RC4, the arrangement generated when KSA step A+3 is set as S A+3 , and let S A+3 The arrangement obtained directly after the first cycle of PRGA is S′ A+3 , at this time the second output byte of PRGA is S′ A+3 [S' A+3 [2]+S' A+3 [S A+3 [1]+S' A+3 [2]]]; in S' A+3 [2]+S' A+3 [S A+3 [1]+S' A+3 [2]]=A+3 is established, and considering the influence of all Swaps on S after the step A+3 of KSA, the second output byte will be S' with a certain probability A+3 [A+3], when S again A+3 [A+3] did not participate in the exchange in the first cycle of the above PRGA with S' A+3 [A+3]=S A+3 [A+3], so at this time S' A+3 [A+3]=S A+3 [A+3]=S A+2 [j A+3 ], search S A+2 The median is S' A+3 The unit of [A+3] can get j A+3 , and get an estimate of the key K[A+3]=j A+3 -j A+2 -S A+2 [i A+3 ].

Description

technical field The invention relates to the technical field of cryptanalysis, and in particular to cracking cryptographic protocols such as WEP based on the RC4 algorithm. Background technique RC4 (Rivest Cipher4, Rivest Cipher 4) is a sequence encryption algorithm invented by RSA Company, and it is one of the most widely used sequence encryption algorithms at present. The RC4 algorithm consists of two parts: 1. key scheduling algorithm (KSA, key timing algorithm): an initial arrangement S composed of elements 0, 1, ..., N-1 is generated by inputting a random key K of L bytes, N is generally 256; 2. Pseudo Random Generation Algorithm (PRGA, pseudo-random generation algorithm): PRGA generates a pseudo-random key sequence by means of S generated by KSA. When encrypting, the pseudo-random key sequence is different or different from the plaintext sequence to obtain the ciphertext sequence. When decrypting, only the same pseudo-random key sequence is d...

AI Technical Summary

Problems solved by technology

After research, when enough IVs that meet the cracking conditions are captured, although the above-mentioned IV Weakness method has a high correct rate of recovering the secret key SK, the cracking time spent at this time is very long

If fewer IVs are captured, the correct rate of cracking is not high enough

Moreover, the IV Weakness method has a higher success rate only when the traversed IV space is large. In practice, the attacker sometimes has no chance to traverse a large IV space, so the original method is not very practical.

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