Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.

Questions tagged [3des]

A block cypher encryption algorithm built from applying three iterations of the original DES algorithm.

Filter by
Sorted by
Tagged with
18
votes
1answer
18k 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) ...
38
votes
1answer
17k views

Why do we use encrypt-decrypt-encrypt (EDE) in 3DES, rather than encrypting three times?

I'm wondering why we use encrypt-decrypt-encrypt (EDE) sequence in 3DES (also known as DES-EDE, TDES or TDEA) with three keys instead of three times encryption (EEE) with three different keys?
2
votes
4answers
11k views

Can I find the encryption key if I know the plain text and the encrypted text (DES and AES)?

If I have the plain text and its output after encryption with a key K1, is it algorithmically feasible to find K1? I am specifically interested in the cases of DES and AES encryption algorithms.
2
votes
1answer
6k views

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 ...
35
votes
2answers
21k views

Is Triple DES still considered safe to use?

What it says on the tin. Is it still used in things like TLS?
2
votes
3answers
19k views

Calculating 3DES Key Check Value (KCV)

I am trying to verify a Triple DES Key Component generated by PC Crypto. The key portion is: E6F1081FEA4C402CC192B65DE367EC3E and the KCV value that should be ...
9
votes
1answer
1k views

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}...
4
votes
2answers
1k views

What is the keyspace of 2-key 3DES?

I am assuming that 2-key 3DES is equivalent to 2DES. I know the key size is 2x56 = 112 bits. Is this key size the same as the keyspace? e.g. Would the keyspace be 112 bits ($2^{112}$)?
3
votes
2answers
4k views

How can 3DES encryption use decryption in the middle step?

I have been reading about the 3DES algorithm and I cannot understand one part. In 3DES we do following operation: $$C=E[K_3,D[K_2,E[K_1,P]]].$$ Where $C$ is ciphertext, $P$ is plaintext, $E$ is DES ...
2
votes
0answers
54 views

Extracting RC4 and 3DES keys from system memory

I have read papers [1], [2] that have presented techniques on extracting symmetric encryption keys from memory during the process of encryption. There are tools [3] that can extract AES keys from ...
0
votes
1answer
258 views

Will two KEK's provide the same KCV or should these be different?

If you were to have an MDKac key that you need to send to two parties you would need to encrypt this key with two different KEK/ZCMKs. Will the KCV of the MDKac under KEK1 provide the same KCV as ...
-1
votes
1answer
2k views

How 3DES work in a simple way?

As I understand DES, It encrypt 64-bit plaintext block with 56-bit key (ECB). So if ...
8
votes
1answer
367 views

Is there a security proof for the Triple-DES construction in the ideal cipher model?

Suppose one has an ideal block cipher $E \: : \: \{0,\hspace{-0.04 in}1\hspace{-0.03 in}\}^k \times \{0,\hspace{-0.04 in}1\hspace{-0.03 in}\}^w \: \to \: \{0,\hspace{-0.04 in}1\hspace{-0.03 in}\}^w \;...
4
votes
1answer
2k views

Effective key length of Two-Key Triple-DES

What's the effective key length of Two-Key Triple-DES, for some (possibly several) reasonably well-defined and sensible definitions of effective key length, say assuming attack using ample chosen ...
2
votes
1answer
2k views

Is a 4DES or 5DES system possible?

We know that 3DES is created with $E_{K_3}(D_{K_2}(E_{K_1}(m)))$ to extend DES's key length. Is it possible to extend it further by repeating this pattern? Perhaps using $E_{K_5}(D_{K_4}(E_{K_3}(D_{...
2
votes
1answer
495 views

Can the key-complement property of DES be used against 3DES?

The comments in this recent question about the security of 3DES made me wonder if the key complement property of DES (which reduces its security by ~1 bit) can be used in the meet-in-the-middle attack ...
2
votes
0answers
28 views

Do I need verifiable shares?

I'm using Shamir's secret sharing in a 2:3 system. Thus a secret Key is split in 3 subkeys (KeyS:KeyC:KeyT) I've 3 entities at ...
2
votes
2answers
2k views

Triple-DES DUKPT CBC PIN variant vs Data variant

Does any know the difference between triple des dukpt decryption algorithm with PIN variant and Data variant? I have done Triple DES DUKPT PIN variant, which generate session key from KSN and BDK. ...
2
votes
3answers
596 views

Can ECB mode really leak some characters?

In an Ars Technica article about Adobe's use of 3DES in ECB mode, there's a paragraph The passwords, according to password expert Steve "Sc00bz" Thomas, are encrypted in a mode known as ECB. That ...
1
vote
2answers
603 views

What is transaction capacity of a POS using 3DES DUKPT?

I am looking for the transaction capacity of a Point-Of-Sale device using 3DES DUKPT. Once all keys derived from the future key set are exhausted (1M or 500K?), how will the POS be reloaded with a new ...
0
votes
1answer
185 views

Creating a message authentication scheme

I have such situation. I have a device like dongle. But it has certain limitations. For example, it can only have implemented encryption and decryption functionality. The availability of ciphers ...
0
votes
1answer
761 views

Discrepancy between 3DES in OpenSSL and PyDES [closed]

I'm trying to encrypt some data using triple DES ECB, but I get a discrepancy between OpenSSL and the pyDES library I'm using. When trying to get a KCV value, I'm using a file consisting of 8 bytes ...
0
votes
1answer
108 views

Usage of 3DES for single block

I have a device, HASP, which has functionality to encrypt 8 byte data using 3DES in ECB mode, with three different keys, I am interested how secure is this? I know it might not be most secure, but how ...
-1
votes
1answer
406 views

Cryptographic methods that do not use prime numbers?

Does anyone know any cryptographic methods that do not use prime numbers? If so, which ones?
-1
votes
2answers
2k views

Retrieving the 3DES decryption key from plaintext and ciphertext?

I have a hex key that I want to decrypt with a 3DES key in mode ECB. For example: ...