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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 ...
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 ...
This table specifies the input permutation on a 64-bit block. The meaning is as follows: the first bit of the output is taken from the 58th bit of the input; the second bit from the 50th bit, and so on, with the last bit of the output taken from the 7th bit of the input.
56-bit DES encryption is now obsolete, having been replaced as a standard in 2002 by the 128-bit (and stronger) Advanced Encryption Standard. DES continues to be used as a symmetric cipher in combination with Kerberos because older products do not support newer ciphers like AES .
The first block cipher to use a form of key whitening is DES-X, which simply uses two extra 64-bit keys for whitening, beyond the normal 56-bit key of DES. This is intended to increase the complexity of a brute force attack , increasing the effective size of the key without major changes in the algorithm.
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.
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.
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.