$\begingroup$ That schematic does not directly apply to DES: it is missing the final swap, IP, FP; and shows decryption with L and R reversed; whereas in DES, thanks to the final swap, encryption and decryption are identical except for the order of subkeys. $\endgroup$ –

2022年7月28日 · Yes, “EDE” means encrypt-decrypt-encrypt for encryption (and decrypt-encrypt-decrypt for decryption). It's implicit in “triple DES” anyway: choosing which direction is encryption and which one is decryption is arbitrary, but the de facto standard choice for triple DES is that 3DES encryption does more 1DES encryption than decryption and ...

2020年2月13日 · I would like to implement fast DES decryption using Bitslice technique. Without bitslice DES technique, I have already done decrpytion in this source code by changing the for loop from 15 to 0. In this source code there is no decryption function for DES. How to implement decryption function using the encyption routine? What modifications can be ...

2018年10月24日 · $\begingroup$ The way the answer is worded, the result of a round's XOR is placed in an R register on encryption, and in a L register on decryption. If you look at a DES implementation in hardware, or at most software ones, that's simply not the case: the exact same code is used for encryption and decryption (except for computation of subkeys).

2018年10月15日 · Would the S boxes be the exact same in the decryption phase as in the encryption phase just in reverse? Wouldn't there be a way to sense the pattern here? I know DES is not the most secure system anyway but this seems even more unsecured? I'm just a bit confused on how the math from encryption to decryption works.

2015年12月20日 · First step of DES is an initial permutation which is key independent and last step of DES is the inverse of this permutation. With EEE the inverse permutation at the end of the first encryption would be cancelled out by the initial permutation of the second encryption (same for inverse of second and initial of third encryption).

2018年2月15日 · So assuming we encrypted using ciphertext = E(k3,D(k2,E(k1,plaintext))), then we can decrypt using 1-DES as follows: temp1 = D(k3,ciphertext) temp2 = E(k2,temp1) plaintext = D(k1,temp2) And of course if we are using something like Cipher Block Chaining, the whole sequence above would be considered one block cipher decryption. Edit: 1.

so, using an hypothetical DES scheme encryption function function_DES(hex_message, hex_key), our hash here would be the output of function_DES(00 00 00 00 00 00 00, cd bf 7e 2c 3c 98 b2). imagine that the output is hashOutput1. 4.We crypt 25 hashOutput1 with the key cd bf 7e 2c 3c 98 b2 using DES scheme.

Assume that 1 evaluation of {DES, AES} takes 10 operations, and we can perform $10^{15}$ operations per second. Trivially, that means we can evaluate $10^{14}$, or about $2^{46.5}$ {DES, AES} encryptions per second. This is a simplistic view: we are ignoring here the cost of testing whether we found the correct key, and the key schedule cost.

2016年10月6日 · $\begingroup$ Actually, encryption and decryption are not the same, but are (given a fixed key) different bijective operations on the set of all blocks ($\{0,1\}^{64}$ for DES). They should be the inverses of each other to be called "encryption" and "decryption", though. Also, welcome to Cryptography Stack Exchange.