(or Data Encryption Standard), a (symmetric) block cipher using a 64 bit block size, with keys of size 56 bit, the standard US block cipher from 1976 to 2001.
0
votes
1answer
39 views
Is the DES algorithm in OPENSSL random?
Look at the hex dumps of encrypted1.bin and encrypted2.bin . They both have same password A which was used to encrypt sampletext
...
-3
votes
0answers
37 views
DES chosen-plaintext attack in Windows [closed]
How do I do a DES chosen-plaintext attack in Windows?
3
votes
1answer
126 views
Triple-DES Brute Force
Shannon's paper states:
A system is pure if all keys are equally likely and if for any three
transformations, $T_i$, $T_j$, $T_k$ in the set, the product
$T_iT_j^{-1}T_k$ is also a ...
10
votes
2answers
3k views
How long does it take to crack DES and AES?
Suppose that a single evaluation of a block-cipher (DES or AES) takes 10 operations, and the computer can do $10^{15}$ such operations per second.
How long would it take for to recover a DES key, ...
-2
votes
2answers
114 views
May the problem with DES using OFB mode be generalized for all feistel ciphers
There is a problem with using DES as the block cipher in OFB mode, eg: the feedback that goes back into the next round will be encrypted with the same key $k$ resulting back into the plaintext IV used ...
0
votes
0answers
57 views
Method and explanation for calculating difference in speed between DES and RSA
Our assignment asks us to convert an RSA speed in bytes per second to a DES speed in bytes per second. Our professor's treatment of this ("RSA is 100 times slower than DES") seems insufficient. Could ...
2
votes
1answer
324 views
Why is triple-DES using three different keys vulnerable to a meet-in-the-middle-attack?
Among other sources, this wikipedia entry states that triple DES using three seperate keys (k1, k2, k3) is vulnerable to meet-in-the-middle-attacks, while triple DES using only two keys (k1, k2, k1) ...
1
vote
1answer
169 views
Can we replace the XOR operation in DES with some other operation?
Can we replace the XOR operation in the DES algorithm with some other operation? If so, does it work for both encryption and decryption?
-1
votes
1answer
116 views
How to bring little changes in DES algorithm
I thought of implementing DES modes of operation as a project...But my guide asked to change or to modify the DES algorithm in such a way to overcome drawbacks of DES...So is there any way to do ...
10
votes
2answers
990 views
Why is MixColumns omitted from the last round of AES?
All rounds of AES (and Rijndael) have a MixColumns step, save the last round which omits it. DES has a similar feature where the last round differs slightly. The rationale, if I recall correctly, ...
5
votes
1answer
61 views
DES key expansion: why are these two descriptions different?
I would like someone to explain me how to generate DES subkeys, because in the documentation that I saw, sometimes they say:
"We rotate the initial key according to the number of iterations given ...
2
votes
1answer
292 views
Brute force attack on DES + property of DES
In a brute force attack on DES, it seems to me that one plaintext-ciphertext pair suffices to launch the attack. (I.e. suppose we are given a message $x$ and a ciphertext $c$ such that $DES_k ( x ) = ...
1
vote
1answer
324 views
Traditional DES scheme in Unix crypt function
In a security context course, we need to reproduce the old DES hashing scheme in the crypt program, on an old unix system.
I am actually reading the crypt page on wikipedia:
The traditional ...
0
votes
2answers
224 views
Cryptanalysis of S-DES - Equations
I am trying to derive equations for s and t in the cryptanalysis of a Simple DES algorithm, but I haven't been able to deduce it. I've attached an image of the portion that I'm referring to, and I'd ...
0
votes
0answers
813 views
How much time will it take to crack Traditional DES encryption? [closed]
I am currently trying to crack a Traditional DES [128/128 BS SSE2] enryption using John the Ripper with ...
2
votes
1answer
181 views
Regarding matsui's Paper on Linear Cryptanalysis of DES
I's going throught the the Paper by Matsui on Linear Cryptanalysis of DES . In that he says
$NS_{5}(16,15)=12$
And then in the next paragraph he says considering the expansion and permutation phases ...
24
votes
3answers
2k views
What are the benefits of the two permutation tables in DES?
Why do we use a permutation table in the first step of DES algorithm and one at the end of algorithm?
4
votes
1answer
190 views
S-box Cryptanalytic Resistance
In DES, different S-boxes were tested for cryptanalytic resistance and the most secure one was chosen for the algorithm itself.
How do different S-boxes offer different levels of security against ...
2
votes
1answer
489 views
ANSI X9.9 Cryptography Standards
I'm trying to create a ISO8583 Rev93 message.
What is the standard way of generating MAC key in ANSI X9.9
DES-CBC encryption algorithm is used to encrypt the ...
1
vote
2answers
352 views
DES Crack simulation
I wish to simulate an implementation of a DES Cracker using verilog. But every paper I read give only abstract hints but no concrete steps or how really to go about it. How is it usually done? For ...
1
vote
1answer
447 views
Verilog simulation of Data Encryption Standard
I interested in developing DES(in verilog) for my college project.Can i get help in understanding the simulation results of DES encryption and decryption ?
thanks in advance .
4
votes
1answer
404 views
Linear Cryptanalysis
What is the principle of linear cryptanalysis, as applied to a block cipher ? For instance, this page gives the rough outline of differential cryptanalysis.
5
votes
1answer
1k views
Avalanche effect in DES
I couldn't understand the avalanche effect in DES. Could someone explain how avalanche effect happens in DES
3
votes
2answers
629 views
Decrypting DES with decrypted and encrypted data
I got two 8 bytestrings
One which is decrypted is:
FF FF FF FF FF FF FF FF
and one which is encrypted is:
16 05 78 B0 0A C2 78 7F
Encryption mode is CipherMode.ECB
I need the key used in DES ...
2
votes
2answers
185 views
How can I encrypt more than 64 bit with the Data Encryption Standard?
The Data Encryption Algorithm is designed to encipher and decipher blocks of data consisting of 64 bits under control of a 56-bit key.
If my data is more than 64 bits, (suppose 66 or 67 bits), will ...
4
votes
1answer
1k views
What are the details of the DES weakness of reusing the same IV in CBC mode with the same key?
I think I once faced the recommendation, that the initialization vector should always be random and never be used twice with the same key.
How serious is this weakness?
Also, is AES less effected ...
15
votes
2answers
1k views
How were the DES S-box values determined?
It seems like the S-boxes in DES have essentially random values.
How were these chosen?
5
votes
3answers
1k views
Is there any opensource white-box implementation of AES or DES?
I googled it and give me no result. There is a binary executable of white-box implementation of DES (scroll down), but no source code provided.
The same page also links various papers about ...
0
votes
1answer
2k views
c# Correct Triple Des Block Encryption Usage
I found the below code online, but in its original state, the encryption was not using any padding (Padding.None), and was encrypting in blocks of 8. I wasn't able to get this code to properly encrypt ...
8
votes
4answers
294 views
Should DES be avoided when developing new systems?
According to wikipedia "DES is now considered to be insecure for many applications".
However, since it can be broken relativily simply, should it not just be avoided for all applications?
