Another Crypto Question

mikeyoung · January 2006

Which of the following is NOT a true 3DES mode?

1. DES-EEE1 uses one key

2. DES-EEE2 uses two keys

3. DES-EEE3 uses three keys

4. DES-EDE2 uses two keys

mikeyoung · February 2006

Answer: A

Explanaiton: The following are the correct modes for triple-DES (3DES): DES-EEE3 uses three keys for encryption and the data is encrypted, encrypted, encrypted; DES-EDE3 uses three keys and encrypts, decrypts and encrypts data. DES-EEE2 and DES-EDE2 are the same as the previous modes, but the first and third operations use the same key. There is no DES-EEE1.

reference: All-in-One CISSP Exam guide 3rd. Ed.: Chapter 8, page 629

Webmaster · February 2006

Hey Mike,

I appreciate what you are trying to do! Even though nobody took an attempt to answer this one, it will remain as valuable info in this forum. I have a request though: please keep the questions in a single topic (i.e. "Question of the Moment") so I can make it a Sticky post, and can add questions occasionally myself. Eventually, i.e. per 10, I can add them to our practice test engine. If you plan to keep this up and have written a bunch of questions, I'll be happy to reward you with an exam voucher or some study material. Feel free to PM me regarding this.

Thanks,
Johan

f2180 · February 2006

I agree with the webmaster although I was unable to access this site the whole of yesterday, (DDOS?) or I would have attempted to answer it. I honestly think Mike is doing a great job.

Webmaster · February 2006

f2180 wrote:

I was unable to access this site the whole of yesterday, (DDOS?)

We should have noticed it (based on traffic stats as well, as intrusion detection system, and I've been only most of the day myself). Feel free to shoot me an email next time though.

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