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Questions tagged [desx]

DESX is an extension of DES that attempts to foil brute force attacks

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0answers
34 views

Please Tell me about book or article that Explain about Mathematical Background Of DES Encryption Algorithms [closed]

Please Tell me about book or article that Explain about Mathematical Background Of DES Encryption Algorithms?
1
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1answer
61 views

Comparing DES and DES-X variation: $Enc(m) = DES_{k_1}(m \oplus k_2)$

I came across this question: Test the security of the following variation of DES-X cryptosystem, which uses 2 keys $k_1$ and $k_2$: $$Enc(m) = DES_{k_1}(m \oplus k_2)$$ (Basically, it uses the 2nd ...
1
vote
2answers
204 views

Some simple questions about tweakable ciphers

I have read a few papers on tweakable ciphers (didn't understand them well, though) and looked at many of the questions and answers on this exchange: What is a tweakable block cipher, Tweakable Block ...
4
votes
2answers
348 views

Why does DESX break if one removed post whitening?

DESX uses whitening to strengthen against brute force attacks. What is an attack one could use to recover DESX's pre-whitening key with only two known ciphertext/plaintext pairs, given that the ...
4
votes
1answer
449 views

Effective key length in DESX variant

We are given a variant of DESX, where $ENC(M)= DES_k(M \oplus k_1)$ (keys are 64bits). In DESX effective key length is $119-lb(M)$ according to wikipedia, but I have not found how this is calculated. ...
2
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0answers
232 views

total effective key length of the AESX-192

If I have a AESX-192 be a block cipher which is similar to DESX but has the DES being replaced by AES and the AES key size is 192 bits. How should I compute the total effective key length of the ...
3
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1answer
3k views

A simple attack on DESX in time $2^{120}$ [duplicate]

Let $\mathcal{M}$ be our message space and $\mathcal{K}$ our key space. Now, let $\mathrm{E} : \mathcal{K} \times \mathcal{M} \to \mathcal{M}$ be a block cipher. Define the block cipher $\mathrm{EX}((...
2
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1answer
458 views

DES-X , computation load and storage

The passage said that the computational load to attack DES-X can be reduced to approximately $2^{(56+64)}=2^{120}$ steps,and the storage of data sets should be $2^{64}$. But I can't figure why it is ...