Linked Questions

9 votes
1 answer

How can I attack a Triple-Block cipher with 2 keys (like 3DES) with a cost of ≤ 2⁵⁶

I am trying to solve something and I have but I have no idea anymore. Maybe anyone of you has an idea/solution/hint. Given is a block cipher $F$ with key length $n$. It looks like this: $$c = ENC_{k1}...
Donut's user avatar
  • 395
6 votes
1 answer

Why does applying 56-bit DES twice only give 57 bits of security? [duplicate]

Given two 56-bit keys, $k_1$ and $k_2$, why does $E_{k_1}(E_{k_2}(M))$ only give 57 bits of security? So basically I'm unsure why it only gives 57 bits of security; I understand that one key will ...
user3411002's user avatar
5 votes
2 answers

Meet-in-the-Middle attack on 3DES [duplicate]

How can I apply the Meet-in-the-Middle attack to the 3DES algorithm, and why does the literature say that 3DES is more secure than DES?
hadil da'na's user avatar
3 votes
1 answer

3DES Modes EED or EDE?

Can we use EED with 2 keys $(k_1, k_1, k_3)$ rather than EDE $(k_1, k_2, k_1)$? We measure the strength of DES by the effort (in terms of the number of tries) in finding some $k_1$ & $k_2$ to ...
Jaee Kshirsagar's user avatar
2 votes
2 answers

Why do 1st and 3rd key have to be the same in 2 key 3DES?

From this answer: However, that wasn't the only situation they had in mind; they also considered the case where someone implemented 2 key 3DES in hardware (which the first and last subkeys were ...
edfg's user avatar
  • 23
2 votes
1 answer

2DES vs. two-key triple encryption, with no decryption step

So studying double encryption (double DES) and understanding why it is subject to a meet-in-the-middle attack, I tried to see if the same attack could be applied to a triple encryption with only two ...
Force444's user avatar
  • 145
2 votes
1 answer

Why is Triple DES not vulnerable to meet in the middle attacks?

Consider the Triple DES encryption calculated as: $$C= E_{K_1}(D_{K_2}(E_{K_1}(P))).$$ For a chosen plaintext attack, given plaintext $P$, we compute the result of $D_{K_2}(E_{K_1}(P))$ and store ...
user avatar
2 votes
1 answer

Quadruple DES vs AES-128 security

I came across this question regarding the security of Quadruple DES (hypothetically DES done four times) in CBC encryption mode vs security of AES-128 in CBC encryption mode. What parameters help to ...
shijuza's user avatar
  • 153
2 votes
1 answer

Triple DES with 2 keys

Suppose triple DES is performed by choosing two keys $K_1$ and $K_2$ and computing $C = T (T (T (L, K_1), K_2), K_2)$. How to attack this modified version with a meet-in-the-middle attack, in which ...
lockerz's user avatar
  • 43
1 vote
3 answers

How much would this AES modification improve security? [closed]

How much would using AES-CTR like 3DES improve security? Like so (Using a 512-bit key split into two; $K_1$ & $K_2$, and seperate nonces for all stages): ...
Legorooj's user avatar
  • 474
0 votes
2 answers

Discrepancy with reported key size for EDE ciphers in Qualys SSL Labs

The following two cipher suites were reported by Qualys SSL Labs as being 112-bit: SSL_CK_DES_192_EDE3_CBC_WITH_MD5 TLS_RSA_WITH_3DES_EDE_CBC_SHA However, all other references I can find say that ...
Polynomial's user avatar
  • 3,527
0 votes
4 answers

Comparison among algorithm based on key length

Some months ago I found in some paper that we cannot compare symmetric algorithm with asymmetric algorithm based on the key length and more important we cannot compare asymmetric algorithm using only ...
mons91's user avatar
  • 3
0 votes
0 answers

Time and space complexity analyzation of meet and middle attack of triple DES

How can we analyze the time and space complexity of meet and middle attack on a Triple-DES?
Sudhir Kumar Sahoo's user avatar
0 votes
3 answers

Is triple DES similiar to RSA in that the message size is limited to the key size?

Is Triple DES similiar to RSA in that the message size you can encrypt is limited (unlike AES)? Yes you can break the message size into parts and apply it, but I'm not interested in doing that so I ...
user1361315's user avatar
-1 votes
1 answer

What is the importance of superencryption?

Please, can any extensively explain the importance of super encryption in relation to attacks experienced by single standard algorithms
Ubochi Chibueze Nwamouh's user avatar