[CCCure CISSP] Q11April-13 Some cccure Quiz question doubts

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[CCCure CISSP] Q11April-13 Some cccure Quiz question doubts

Amlan Deb
Hi guys,
 
I have some doubts regarding some cccure Quiz questions and concepts mentioned below. Would really appreciate it if you could take out some time and help me with them.
 
Thanks,
Amlan
 

Doubt#11
========
 

124. 

1.     Question: 1397 | Difficulty: 3/5 | Relevancy: 3/3

What key size is used by the Clipper Chip?

o      40 bits

o      56 bits

o      64 bits

o     80 bits

You did not provide any answer to this question. Please review details below.

The Clipper Chip is a NSA designed tamperproof chip for encrypting data and it uses the SkipJack algorithm. Each Clipper Chip has a unique serial number and a copy of the unit key is stored in the database under this serial number. The sending Clipper Chip generates and sends a Law Enforcement Access Field (LEAF) value included in the transmitted message. It is based on a 80-bit key and a 16-bit checksum.
Source: WALLHOFF, John,
CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 1). Available at http://www.cccure.org.

Last modified 07/02/2007, Ron Hehemann

Contributor: Christian Vezina

 

My doubt:  Wasn’t able to understand the explanation highlighted in Blue. Please explain with an example if possible. Below is some additional info I could gather regarding Clipper chip but I was still unable to understand what is being explained above.

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Re: [CCCure CISSP] Q11April-13 Some cccure Quiz question doubts

Amlan Deb
 
Sorry a portion of the mail was not copied properly earlier. Please ignore earlier mail and consider this one.
 
Thanks,
Amlan

--- On Fri, 5/24/13, Amlan Deb <[hidden email]> wrote:

From: Amlan Deb <[hidden email]>
Subject: Q11April-13 Some cccure Quiz question doubts
To: [hidden email]
Date: Friday, May 24, 2013, 7:32 PM

Hi guys,
 
I have some doubts regarding some cccure Quiz questions and concepts mentioned below. Would really appreciate it if you could take out some time and help me with them.
 
Thanks,
Amlan
 

Doubt#11
========
 

124. 

1.     Question: 1397 | Difficulty: 3/5 | Relevancy: 3/3

What key size is used by the Clipper Chip?

o      40 bits

o      56 bits

o      64 bits

o     80 bits

You did not provide any answer to this question. Please review details below.

Details

Submit a comment on this question

The Clipper Chip is a NSA designed tamperproof chip for encrypting data and it uses the SkipJack algorithm. Each Clipper Chip has a unique serial number and a copy of the unit key is stored in the database under this serial number. The sending Clipper Chip generates and sends a Law Enforcement Access Field (LEAF) value included in the transmitted message. It is based on a 80-bit key and a 16-bit checksum.
Source: WALLHOFF, John,
CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 1). Available at http://www.cccure.org.

Last modified 07/02/2007, Ron Hehemann

Contributor: Christian Vezina

 

My doubt:  Wasn’t able to understand the explanation highlighted in Blue. Please explain with an example if possible. Below is some additional info I could gather regarding Clipper chip but I was still unable to understand what is being explained above.

The heart of the Clipper Chip concept was key escrow. In the factory, any new telephone or other device with a Clipper chip would be given a "cryptographic key", that would then be provided to the government in "escrow".  If government agencies "established their authority" to listen to a communication, then the password would be given to those government agencies, who could then decrypt all data transmitted by that particular telephone.

The CISSP Prep Guide states, "The idea is to divide the key into two parts, and to escrow two portions of the key with two separate 'trusted' organizations. Then, law enforcement officals, after obtaining a court order, can retreive the two pieces of the key from the organizations and decrypt the message."


_______________________________________________
You can find the list archive at:
http://cissp-study.3965.n7.nabble.com/

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To UNSUBSCRIBE, SUBSCRIBE, or MANAGE your accout visit the link below:
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