1
vote
1answer
45 views

DES Encryption Algorithm all 64 bits for key instead of 56 bits

Would a DES algorithm that uses all 64 bits for the key instead of just the 56 bits be more secure? I have been thinking about it but those 8 bits used for parity are very useful and but including ...
6
votes
3answers
213 views

Rainbow table for DES with all-zero plaintext?

Consider the function $F$ from $\{0,1\}^{56}$ to $\{0,1\}^{64}$, mapping the operative bits of a DES key to the ciphertext for all-zero plaintext. How could we organize a rainbow table to invert that ...
2
votes
2answers
184 views

DES with actual 7 byte key

Do we have any library or any mechanism where we can use true 7 byte key for DES instead of 8 byte key. I need it for keys analysis in DES and 8 byte key requirement for associated library is creating ...
1
vote
1answer
66 views

Perl DES PCBC as protection against decryption/crypt analysis

Is error propagation in DES PCBC a good method to prevent decryption/crypt analysis by third parties? If I had a very large file encrypted with Perl's DES with the PCBC option, and then removed the ...
1
vote
1answer
88 views

Can I use the cipher text ouput of only one DES rotation as plaintext to check validity?

I have made a python code for one DES rotation. Can I use the resulting cipher text as a plain text for the same rotation with the same key? I think the answer is no, I can't do so. But I need to be ...
3
votes
2answers
281 views

DES — Can I recover the key when I have both ciphertext and the plaintext?

Given a message and DES encrypted form of said message, is it possible to efficiently compute the key used to encrypt the data?
5
votes
1answer
1k views

Can you explain “weak keys” for DES?

A weak key for DES is a key $K$ such that $DES_{k_1}(DES_{k_2}(x))=x$ for all $x$. I don't get why are the 4 keys $k_1||k_2$: $1^{112}$, $0^{112}$, $0^{56}||1^{56}$, $1^{56}||0^{56}$ considered as ...
2
votes
1answer
127 views

Can you help me with this DES variant analysis?

I'm struggling with some DES variant that I got as an exercise (exercise taken from Katz-Lindell Ex5.14). The variant is as follows: The left half of the master key is used to derive all the ...
2
votes
1answer
112 views

Decryption or attacking DES encrypted file

I have a file that has been encrypted using DES and am looking to decrypt and find a secret message encoded. All I have is the file which is full of binary data. There is no key or anything else which ...
1
vote
2answers
330 views

How do we prove that AES, DES etc. are secure?

How do we prove that AES, DES etc. are secure? I've read about them and know the basics on how they work, but I still don't quite understand how we can be sure they are secure? What are the proofs?
8
votes
2answers
690 views

Why does DES use exactly 16 rounds?

Why does DES use exactly 16 rounds and not more or less than 16? What is the significance of using 16 rounds?
2
votes
1answer
247 views

How insecure in practice?

I am in attempt to understand relative insecurity of certain encryption schemes. Particularly of interest is DES and RC2. I know AES is better and should be used to encrypt. But practically, if ...
1
vote
2answers
473 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 ...
2
votes
1answer
241 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 ...
11
votes
1answer
1k views

Duration for attacking Two-Key Triple-DES Encryption using all RAM ever built?

I am considering attacks on Two-Key Triple-DES Encryption assuming $2^{32}$ known plaintext/ciphertext pairs (that's a mere 32 Giga Bytes of ciphertext) by the method devised by Paul C. van Oorschot ...
5
votes
1answer
260 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
2answers
477 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 ...
2
votes
1answer
626 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 .
6
votes
1answer
671 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.
3
votes
2answers
1k views

Decrypting DES with decrypted and encrypted data

I got two 8-byte strings. One which is decrypted is: FF FF FF FF FF FF FF FF and one which is encrypted is: ...