翻訳と辞書 Words near each other ・ Md. Moniruzzaman Moni ・ Md. Muzammel Hossain ・ Md. Sabur Khan ・ Md. Sohrab ・ Md. Tafazzul Islam ・ Md. Tofazzal Islam ・ MD.45 ・ MD1 ・ MD2 ・ MD2 (cryptography) ・ MD2 (file format) ・ MD3 ・ MD3 (file format) ・ MD4 ・ MD5 ・ MD5CRK ・ Md5deep ・ Md5sum ・ MD6 ・ MD7 ・ MDA ・ MDA (TV series) ・ MDA framework ・ MDA Muscle Walk ・ MDA Space Missions ・ MDA-19 ・ MDA-MB-468 ・ MDA5 ・ MDAC (disambiguation) ・ Mdadm Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク MD5CRK ： ウィキペディア英語版 MD5CRK In cryptography, MD5CRK was a distributed effort (similar to distributed.net) launched by Jean-Luc Cooke and his company, (CertainKey Cryptosystems ), to demonstrate that the MD5 message digest algorithm is insecure by finding a collision — two messages that produce the same MD5 hash. The project went live on March 1, 2004. The project ended on August 24, 2004 after researchers independently demonstrated a technique for generating collisions in MD5 using analytical methods by Xiaoyun Wang, Feng, Xuejia Lai, and Yu(). (CertainKey ) awarded a 10,000 Canadian Dollar (prize to Wang, Feng, Lai and Yu ) for their discovery. A technique called Floyd's cycle-finding algorithm was used to try to find a collision for MD5. The algorithm can be described by analogy with a random walk. Using the principle that any function with a finite number of possible outputs placed in a feedback loop will cycle, one can use a relatively small amount of memory to store outputs with particular structures and use them as "markers" to better detect when a marker has been "passed" before. These markers are called ''distinguished points'', the point where two inputs produce the same output is called a ''collision point''. MD5CRK considered any point whose first 32 bits were zeroes to be a distinguished point. ==Complexity== The expected time to find a collision is not equal to $2^$ where $N$ is the number of bits in the digest output. It is in fact $2^N!\; \backslash over$, where $K$ is the number of function outputs collected. For this project, the probability of success after $K$ MD5 computations can be approximated by: $1\; \backslash over\; \}$. The expected number of computations required to produce a collision in the 128-bit MD5 message digest function is thus: $\}$ To give some perspective to this, using (Virginia Tech's System X ) with a max performance of 12.25 Teraflops, it would take approximately $\backslash approx\; 1,770,000\}$ seconds or about 3 weeks. Or for commodity processors at 2 gigaflops it would take 6,000 machines approximately the same amount of time. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「MD5CRK」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.