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For DES, questions were raised about the adequacy of its key size early on, even before it was adopted as a standard, and it was the small key size, rather than theoretical cryptanalysis, which dictated a need for a replacement algorithm. As a result of discussions involving external consultants including the NSA, the key size was reduced from ...
This table lists the eight S-boxes used in DES. Each S-box replaces a 6-bit input with a 4-bit output. Given a 6-bit input, the 4-bit output is found by selecting the row using the outer two bits, and the column using the inner four bits.
DES Challenge II-1 was solved by distributed.net in 39 days in early 1998. The plaintext message being solved for was "The secret message is: Many hands make light work." [2] DES Challenge II-2 was solved in just 56 hours in July 1998, by the Electronic Frontier Foundation (EFF), with their purpose-built Deep Crack machine. EFF won $10,000 for ...
In cryptography, the EFF DES cracker (nicknamed "Deep Crack") is a machine built by the Electronic Frontier Foundation (EFF) in 1998, to perform a brute force search of the Data Encryption Standard (DES) cipher's key space – that is, to decrypt an encrypted message by trying every possible key.
DES has a key schedule in which the 56-bit key is divided into two 28-bit halves; each half is thereafter treated separately. In successive rounds, both halves are rotated left by one or two bits (specified for each round), and then 48 round key bits are selected by Permuted Choice 2 (PC-2) – 24 bits from the left half and 24 from the right.
DES also has semi-weak keys, which only produce two different subkeys, each used eight times in the algorithm: This means they come in pairs K 1 and K 2, and they have the property that: (()) = where E K (M) is the encryption algorithm encrypting message M with key K. There are six semi-weak key pairs:
In cryptography, DES-X (or DESX) is a variant on the DES (Data Encryption Standard) symmetric-key block cipher intended to increase the complexity of a brute-force attack. The technique used to increase the complexity is called key whitening. The original DES algorithm was specified in 1976 with a 56-bit key size: 2 56 possibilities for the key.
A discrete-event simulation (DES) models the operation of a system as a sequence of events in time. Each event occurs at a particular instant in time and marks a change of state in the system. [ 1 ] Between consecutive events, no change in the system is assumed to occur; thus the simulation time can directly jump to the occurrence time of the ...