# Questions tagged [3des]

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

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### 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) ...
16k 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?
10k 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.
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 ...
20k views

### Is Triple DES still considered safe to use?

What it says on the tin. Is it still used in things like TLS?
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 ...
1k views

249 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 ...
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 ...
356 views

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### 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 ...
568 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 ...
49 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 ...
724 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 ...
101 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 ...
183 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 ...