1 vote
304 views

Triple DES 1 key to simulate 3 keys

I saw a statement that the probability of finding a key $k'$ to simulate 3 keys $k_1$, $k_2$, $k_3$ is neglectable: $\mathrm{Enc}(k_3,\mathrm{Enc}(k_2,\mathrm{Enc}(k_1,x))) = \mathrm{Enc}(k′,x)$ When ...
437 views

Why do we encrypt then decrypt then encrypt data with different keys?

In GlobalPlatform specification for smartcards, I came accross this rather strange scheme* ISO/IEC ISO/IEC 9797-1 MAC Algorithm 3: To calculate the Message Authentication Code, we take some original ...
2k views

Triple AES-128 encryption with 2 keys

We have a system where two devices communicate. Due to restrictions on one of them, we can only use AES-128 (so no AES-256) for encrypting the communication. However, new requirements on these kinds ...
1k views

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 ...
5k views

Modes of Triple DES - When to use each?

I'm studying for CISSP certification & am using Shon Harris Exam Guide. It states that there are 4 modes that Triple-DES can be used in: DES-EEE3 DES-EDE3 DES-EEE2 DES-EDE2 I understand these ...
1 vote
1k views

No of keys used in Triple DES Algorithm

I am studying Triple DES. I have got two basic questions. One, why are we following a sequence like encrypt(decrypt(encrypt)); what is the problem using a sequence encrypt(encrypt(encrypt))? Second,...
64 views

triple-des simple questtion [duplicate]

Why do we use encrypt-decrypt-encrypt (EDE) in 3DES, rather than encrypting three times? in this link, we use EDE Mode usually. when we use one key, in this case, Encryption -> Decryption result ...
899 views

Triple Data Encryption Standard [closed]

Based on this, it looks like something slightly wrong. What would need to be adjusted at the transmitter side to allow the receiver to decrypt the message/data?