Encryption Challenge
| Good [+1]Toggle ReplyLink» neoform replied on Tue Feb 17, 2009 @ 6:32pm |
 Coolness: 339775 | Go read up on the Poincaré conjecture then tell me you can prove it's wrong. |
| I'm feeling pompous right now.. | |
| Good [+1]Toggle ReplyLink» Nathan replied on Tue Feb 17, 2009 @ 6:33pm |
 Coolness: 166655 | i'd rather have the 5 bucks. |
| I'm feeling you up right now.. | |
| Good [+1]Toggle ReplyLink» neoform replied on Tue Feb 17, 2009 @ 6:34pm |
| Coolness: 339775 | St. Laurent and St. Cath is a great place, stand on the corner for a while. Actually, you're a pretty ugly bastard, you might have to give five $1 BJs..  |
| I'm feeling pompous right now.. | |
| Good [+1]Toggle ReplyLink» Nathan replied on Tue Feb 17, 2009 @ 6:37pm |
| Coolness: 166655 | ...thnx for the invite, but i really don't want to come to your place. |
| I'm feeling you up right now.. | |
| Good [+1]Toggle ReplyLink» neoform replied on Tue Feb 17, 2009 @ 6:46pm |
| Coolness: 339775 | Why not? My box can easily fit another person.. well, at least half a person. |
| I'm feeling pompous right now.. | |
| Good [+1]Toggle ReplyLink» JasonBeastly replied on Tue Feb 17, 2009 @ 7:00pm |
 Coolness: 76820 | 0b01!!11 h4><! |
| I'm feeling gwan bottirass right now.. | |
| Good [+1]Toggle ReplyLink» cutterhead replied on Tue Feb 17, 2009 @ 8:54pm |
 Coolness: 131705 | persistent hey ? lol Update » cutterhead wrote on Tue Feb 17, 2009 @ 8:56pm they might have closed you mind neoform , but i wont let you do the same on me. sorry it will be cracked on day. |
| I'm feeling 4hz even if you dont right now.. | |
| Good [+1]Toggle ReplyLink» Mico replied on Tue Feb 17, 2009 @ 8:58pm |
 Coolness: 150570 | No it won't. |
| I'm feeling cool right now.. | |
| Good [+1]Toggle ReplyLink» cutterhead replied on Tue Feb 17, 2009 @ 9:02pm |
| Coolness: 131705 | Conjecture de Poincaré
Un long chemin vers sa résolution En l'an 2000, l'Institut de mathématiques Clay a mis à prix la conjecture de Poincaré et offre un prix d'un million de dollars pour sa solution, ce qui en fait l'un des sept problèmes les plus recherchés du millénaire. La conjecture a induit une longue liste de preuves incorrectes et certaines d'entre elles ont mené à une meilleure compréhension de la topologie en petites dimensions. Progrès récents Vers la fin de l'année 2002, des publications sur l'arXiv de Grigori Perelman de l'institut de mathématiques Steklov de Saint-Pétersbourg laissent penser qu'il pourrait avoir trouvé une preuve de la « conjecture de géométrisation » (voir plus ci-dessous), mettant en œuvre un programme décrit plus tôt par Richard Hamilton. En 2003, il publia un deuxième rapport et donna une série de conférences aux États-Unis. En 2006, un consensus d'experts a conclu que le travail récent de Grigori Perelman en 2003 résolvait ce problème, plus d'un siècle après son premier énoncé. Cette reconnaissance a été annoncée officiellement lors du congrès international de mathématiques le 22 Août 2006 à Madrid au cours duquel la médaille Fields lui a été décernée conjointement avec trois autres mathématiciens. Cependant Perelman a refusé la médaille et la somme qui l'accompagne. Perelman a également refusé le prix Clay. SO YEA IT WILL . KEEP TRYING USING FRENCH WORDS -YOU- DONT UNDERSTAND. |
| I'm feeling 4hz even if you dont right now.. | |
| Good [+1]Toggle ReplyLink» ONE.LAB.RAT replied on Tue Feb 17, 2009 @ 9:03pm |
 Coolness: 76250 | my penus has AES-256 to encrypt it and Whirlpool as the hash algorithm. |
| I'm feeling hhhhhhhh right now.. | |
| Good [+1]Toggle ReplyLink» cutterhead replied on Tue Feb 17, 2009 @ 9:06pm |
| Coolness: 131705 | Labels: whirlpool et maytag Update » cutterhead wrote on Tue Feb 17, 2009 @ 9:28pm buckminister fuller gave us formulas to calculate buckyballs in 3d ans even more dimentions.
great man , wasent afraid of numbers... Update » cutterhead wrote on Tue Feb 17, 2009 @ 9:31pm conclu que le travail récent de Grigori Perelman en 2003 résolvait ce problème Update » cutterhead wrote on Tue Feb 17, 2009 @ 9:34pm even if it was a Hyperboloid structure for the salt number its still would be decypherable Update » cutterhead wrote on Tue Feb 17, 2009 @ 11:17pm . Because of the birthday paradox, it is likely that for every 4096 packets, two will share the same IV and hence the same RC4 key, allowing the packets to be attacked. Far more deadly attacks take advantage of certain weak keys in RC4 and eventually allow the WEP key itself to be recovered. In 2005, agents from the U.S. Federal Bureau of Investigation publicly demonstrated the ability to do this with widely available software tools in about three minutes.[1] Update » cutterhead wrote on Wed Feb 18, 2009 @ 1:55am XSL attack
From Wikipedia, the free encyclopedia Jump to: navigation, search In cryptography, the XSL attack is a method of cryptanalysis for block ciphers. The attack was first published in 2002 by researchers Nicolas Courtois and Josef Pieprzyk. It has caused some controversy as it was claimed to have the potential to break the Advanced Encryption Standard (AES) cipher—also known as Rijndael—faster than an exhaustive search. Since AES is already widely used in commerce and government for the transmission of secret information, finding a technique that can shorten the amount of time it takes to retrieve the secret message without having the key could have wide implications. In 2004 it was shown by Claus Diem [1], that the algorithm does not perform as promised in the paper. In addition, the method has a high work-factor, which unless lessened, means the technique does not reduce the effort to break AES in comparison to an exhaustive search. Therefore, it does not affect the real-world security of block ciphers in the near future. Nonetheless, the attack has caused some experts to express greater unease at the algebraic simplicity of the current AES. In overview, the XSL attack relies on first analyzing the internals of a cipher and deriving a system of quadratic simultaneous equations. These systems of equations are typically very large, for example 8000 equations with 1600 variables for the 128-bit AES. Several methods for solving such systems are known. In the XSL attack, a specialized algorithm, termed XSL (eXtended Sparse Linearization), is then applied to solve these equations and recover the key. The attack is notable for requiring only a handful of known plaintexts to perform; previous methods of cryptanalysis, such as linear and differential cryptanalysis, often require unrealistically large numbers of known or chosen plaintexts. Contents * 1 Solving multivariate quadratic equations * 2 Application to block ciphers * 3 References * 4 External links [edit] Solving multivariate quadratic equations Solving multivariate quadratic equations (MQ) is an NP-hard problem (in the general case) with several applications in cryptography. The XSL attack requires an efficient algorithm for tackling MQ. In 1999, Kipnis and Shamir showed that a particular public key algorithm—known as the Hidden Field Equations scheme (HFE)—could be reduced to an overdetermined system of quadratic equations (more equations than unknowns). One technique for solving such systems is linearization, which involves replacing each quadratic term with an independent variable and solving the resultant linear system using an algorithm such as Gaussian elimination. To succeed, linearization requires enough linearly independent equations (approximately as many as the number of terms). However, for the cryptanalysis of HFE there were too few equations, so Kipnis and Shamir proposed re-linearization, a technique where extra non-linear equations are added after linearization, and the resultant system is solved by a second application of linearization. Re-linearization proved general enough to be applicable to other schemes. In 2000, Courtois et al. proposed an improved algorithm for MQ known as XL (for eXtended Linearization), which increases the number of equations by multiplying them with all monomials of a certain degree. Complexity estimates showed that the XL attack would not work against the equations derived from block ciphers such as AES. However, the systems of equations produced had a special structure, and the XSL algorithm was developed as a refinement of XL which could take advantage of this structure. In XSL, the equations are multiplied only by carefully selected monomials, and several variants have been proposed. Research into the efficiency of XL and its derivative algorithms remains ongoing (Yang and Chen, 2004). In 2005 Cid and Leurent gave evidence that, in its proposed form, the XSL algorithm does not provide an efficient method for solving the AES system of equations; however Courtois disputes their findings. [edit] Application to block ciphers Courtois and Pieprzyk (2002) observed that AES (Rijndael) and partially also Serpent could be expressed as a system of quadratic equations. The variables represent not just the plaintext, ciphertext and key bits, but also various intermediate values within the algorithm. The S-box of AES appears to be especially vulnerable to this type of analysis, as it is based on the algebraically simple inverse function. Subsequently, other ciphers have been studied to see what systems of equations can be produced (Biryukov and De Cannière, 2003), including Camellia, KHAZAD, MISTY-1 and KASUMI. Unlike other forms of cryptanalysis, such as differential and linear cryptanalysis, only one or two known plaintexts are required. The XSL algorithm is tailored to solve the type of equation systems that are produced. Courtois and Pieprzyk estimate that an "optimistic evaluation shows that the XSL attack might be able to break Rijndael [with] 256 bits and Serpent for key lengths [of] 192 and 256 bits." Their analysis, however, is not universally accepted. For example: "I believe that the Courtois-Pieprzyk work is flawed. They overcount the number of linearly independent equations. The result is that they do not in fact have enough linear equations to solve the system, and the method does not break Rijndael...The method has some merit, and is worth investigating, but it does not break Rijndael as it stands." –Don Coppersmith, [2]. In AES 4 Conference, Bonn 2004, one of the inventors of Rijndael, Vincent Rijmen, commented, "The XSL attack is not an attack. It is a dream." [3] Promptly Courtois answered "It will become your nightmare". Most professional cryptographers think that Courtois' answer is just it: fun and nothing more. In 2003, Murphy and Robshaw discovered an alternative description of AES, embedding it in a larger cipher called "BES", which can be described using very simple operations over a single field, GF(28). An XSL attack mounted on this system yields a simpler set of equations which would break AES with complexity of around 2100, if the Courtois and Pieprzyk analysis is correct. In a paper in the AES 4 Conference (Lecture Notes in Computer Science 3373), Toli and Zanoni proved that the work of Murphy and Robshaw is flawed too. Even if XSL works against some modern algorithms, the attack currently poses little danger in terms of practical security. Like many modern cryptanalytic results, it would be a so-called "certificational weakness": while faster than a brute force attack, the resources required are still huge, and it is very unlikely that real-world systems could be compromised by using it. Future improvements could increase the practicality of an attack, however. Because this type of attack is new and unexpected, some cryptographers have expressed unease at the algebraic simplicity of ciphers like Rijndael. Bruce Schneier and Niels Ferguson write, "We have one criticism of AES: we don't quite trust the security…What concerns us the most about AES is its simple algebraic structure… No other block cipher we know of has such a simple algebraic representation. We have no idea whether this leads to an attack or not, but not knowing is reason enough to be skeptical about the use of AES." (Practical Cryptography, 2003, pp56-57) [edit] References * Alex Biryukov, Christophe De Cannière (2003). "Block Ciphers and Systems of Quadratic Equations". LNCS 2887: 274–289. doi:10.1007/b93938. [ citeseer.ist.psu.edu ] * Nicolas Courtois, Alexander Klimov, Jacques Patarin, Adi Shamir (2000). "Efficient Algorithms for Solving Overdefined Systems of Multivariate Polynomial Equations" (PDF). LNCS 1807: 392–407. doi:10.1007/3-540-45539-6_27. [ www.iacr.org ] * Nicolas Courtois, Josef Pieprzyk (2002). "Cryptanalysis of Block Ciphers with Overdefined Systems of Equations". LNCS 2501: 267-287. doi:10.1007/3-540-36178-2_17. [ eprint.iacr.org ] * Aviad Kipnis, Adi Shamir (1999). "Cryptanalysis of the HFE Public Key Cryptosystem by Relinearization". LNCS 1666: 19–30. doi:10.1007/3-540-48405-1_2. [ citeseer.ist.psu.edu ] * Dana Mackenzie (2003). "A game of chance". New Scientist 178 (2398): 36. * Sean Murphy, Matthew J. B. Robshaw (2002). "Essential Algebraic Structure within the AES". LNCS 2442: 1–16. doi:10.1007/3-540-45708-9_1. [ citeseer.ist.psu.edu ] * S. Murphy, M. Robshaw Comments on the Security of the AES and the XSL Technique. * Bo-Yin Yang, Jiun-Ming Chen (2004). "Theoretical Analysis of XL over Small Fields". LNCS 3108: 277-288. doi:10.1007/b98755. [ www.springerlink.com ] * C. Cid, G. Leurent (2005). "An Analysis of the XSL Algorithm" (PDF). LNCS 3788: 333-335. doi:10.1007/11593447. [ www.isg.rhul.ac.uk ] * C. Diem (2004). "The XL-Algorithm and a Conjecture from Commutative Algebra". LNCS 3329: 323-337. doi:10.1007/b104116. [ www.iacr.org ] [edit] External links * Courtois' page on AES * "Quadratic Cryptanalysis", an explanation of the XSL attack by J. J. G. Savard * "AES is NOT broken" by T. Moh * Courtois and Pieprzyk paper on ePrint * Commentary in the Crypto-gram newsletter: [4], [5], [6]. * An overview of AES and XSL v • d • e Block ciphers Common algorithms: AES | Blowfish | DES | Triple DES | Serpent | Twofish Other algorithms: 3-Way | ABC | Akelarre | Anubis | ARIA | BaseKing | BassOmatic | BATON | BEAR and LION | C2 | Camellia | CAST-128 | CAST-256 | CIKS-1 | CIPHERUNICORN-A | CIPHERUNICORN-E | CLEFIA | CMEA | Cobra | COCONUT98 | Crab | CRYPTON | CS-Cipher | DEAL | DES-X | DFC | E2 | FEAL | FEA-M | FROG | G-DES | GOST | Grand Cru | Hasty Pudding cipher | Hierocrypt | ICE | IDEA | IDEA NXT | Intel Cascade Cipher | Iraqi | KASUMI | KeeLoq | KHAZAD | Khufu and Khafre | KN-Cipher | Ladder-DES | Libelle | LOKI97 | LOKI89/91 | Lucifer | M6 | M8 | MacGuffin | Madryga | MAGENTA | MARS | Mercy | MESH | MISTY1 | MMB | MULTI2 | MultiSwap | New Data Seal | NewDES | Nimbus | NOEKEON | NUSH | Q | RC2 | RC5 | RC6 | REDOC | Red Pike | S-1 | SAFER | SAVILLE | SC2000 | SEED | SHACAL | SHARK | Skipjack | SMS4 | Spectr-H64 | Square | SXAL/MBAL | Threefish | TEA | Treyfer | UES | Xenon | xmx | XTEA | XXTEA | Zodiac Design: Feistel network | Key schedule | Product cipher | S-box | P-box | SPN Attacks: Brute force | Linear / Differential / Integral cryptanalysis | Mod n | Related-key | Slide | XSL Standardization: AES process | CRYPTREC | NESSIE Misc: Avalanche effect | Block size | IV | Key size | Modes of operation | Piling-up lemma | Weak key | Key whitening v • d • e Cryptography History of cryptography · Cryptanalysis · Cryptography portal · Topics in cryptography Symmetric-key algorithm · Block cipher · Stream cipher · Public-key cryptography · Cryptographic hash function · Message authentication code · Random numbers · Steganography Retrieved from [ en.wikipedia.org ] Category: Cryptographic attacks Update » cutterhead wrote on Wed Feb 18, 2009 @ 1:30pm 
know enought on lineraisation that youll realise that circuit developpers have to cope themselves with far worse poincare problems since the only way to make a true linear appliance is thru this calculus. your solution is a linear path that can be identify no matter how much disturbance you may want to cause. Update » cutterhead wrote on Wed Feb 18, 2009 @ 1:33pm noah the edit function fo rupdates would be apreciated
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