[Cisspstudy] cisspstudy Digest, Vol 19, Issue 16

Saurabh Bhargava catchbhargava at yahoo.com
Tue Jan 19 17:53:33 EST 2010


Jonus, here is the catch.

you say " For each user, there are 10 public keys. 10 users imply 100 public keys" - but ALL these public keys are the same for all 10 users, they aren't different so 10 users still will imply 10 Public keys , even though author says "fully" communicate/Mesh technology. 

Tom, I would select the answers you've chosen for both the questions. 

Cheers, SB



________________________________
From: gerritsjs <gerritsjs at gmail.com>
To: The CISSP Study Mailing list <cisspstudy at cccure.org>; Nimal Gunarathna <ng949 at yahoo.com>
Sent: Tue, 19 January, 2010 22:02:56
Subject: Re: [Cisspstudy] cisspstudy Digest, Vol 19, Issue 16

Nimal, Tom; 

  The question is "fully" communicated.  Within a community of 10 users,
each user will have one private key.  So we have 10 private keys.  Public
keys are as follows:  
   For each user, there are 10 public keys. 10 users imply 100 public keys.
  This makes a total of 110 keys.  
  
Think of a Mesh Technology. 

Jonus

-----Original Message-----
From: cisspstudy-bounces at cccure.org [mailto:cisspstudy-bounces at cccure.org]
On Behalf Of twitwicki at hannaford.com
Sent: Tuesday, January 19, 2010 1:23 PM
To: Nimal Gunarathna
Cc: cisspstudy at cccure.org
Subject: Re: [Cisspstudy] cisspstudy Digest, Vol 19, Issue 16



Hi Nimal,
      I followed the same logic as you on this question.  In order to get
to the 110 answer each public key would have to be counted each time it's
used which doesn't make sense.  I've come across other examples from this
book that are very questionable, which leads me to believe that the
questions and answers have not been thouroughly vetted.  Thank you for the
reply.

Tom Witwicki, CIPP
Director, Information Security
Hannaford Bros. Co.
207-885-2073

Join me on Linkedin!
http://www.linkedin.com/in/tomwitwicki






                                                                          
             Nimal Gunarathna                                              
             <ng949 at yahoo.com>                                            
                                                                        To 
             01/19/2010 04:07          cisspstudy at cccure.org              
             PM                                                         cc 
                                      twitwicki at hannaford.com            
                                                                   Subject 
                                       Re: cisspstudy Digest, Vol 19,      
                                       Issue 16                            
                                                                          
                                                                          
                                                                          
                                                                          
                                                                          
                                                                          




                                                                            
Hi Tom,                                                                    
                                                                            
This question puzzles me..                                                
In an asymmetric system how many keys are required for 10 users to fully  
communicate?                                                              
                                                                            
Every user has a one private and a one public key. I can send my same      
public                                                                    
key to all others. For 10 people, 20 keys are needed.. I am not sure how  
110 come from?                                                            
Is this a private com session or just a different comm session with each  
pair?                                                                      
                                                                            
Thanks,                                                                    
                                                                            
Nimal Gunarathna                                                          
                                                                            
                                                                            
                                                                            
--- On Tue, 1/19/10, cisspstudy-request at cccure.org                        
<cisspstudy-request at cccure.org> wrote:                                    
                                                                            
  From: cisspstudy-request at cccure.org <cisspstudy-request at cccure.org>      
  Subject: cisspstudy Digest, Vol 19, Issue 16                              
  To: cisspstudy at cccure.org                                                
  Date: Tuesday, January 19, 2010, 11:00 AM                                
                                                                            
  Send cisspstudy mailing list submissions to                              
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  Today's Topics:                                                          
                                                                            
     1. cisspstudy  - Cryptography questions (twitwicki at hannaford.com)      
     2. Re: New to CISSP Cert (Mark Price)                                  
     3. Re: New to CISSP Cert (jack wang)                                  
     4. Re: New to CISSP Cert (Jeronimo Zucco)                              
                                                                            
                                                                            
  ----------------------------------------------------------------------    
                                                                            
  Message: 1                                                                
  Date: Mon, 18 Jan 2010 14:48:26 -0500                                    
  From: twitwicki at hannaford.com                                            
  To: cisspstudy at cccure.org                                                
  Subject: [Cisspstudy] cisspstudy  - Cryptography questions                
  Message-ID:                                                              
      <                                                                    
  OF8F407D94.BBDB76DE-ON852576AF.006B4314-852576AF.006CCD97 at hannaford.com>  
                                                                            
  Content-Type: text/plain; charset=US-ASCII                                
                                                                            
                                                                            
                                                                            
  Hello all,                                                                
        I'd like your thoughts on these questions from Michael Gregg's      
  CISSP                                                                    
  Practice questions:                                                      
                                                                            
  In an asymmetric system how many keys are required for 10 users to fully  
  communicate?                                                              
                                                                            
  A. 10                                                                    
  B. 20                                                                    
  C. 45                                                                    
  D 110                                                                    
                                                                            
  The answer states D. 110 -  "Each user would have his private, phus his  
  public key, plus each of the nine other public keys"                      
  Shouldn't the answer be B. 20  because the public keys is only couned    
  once                                                                      
  for each private/public pair?  This also seems consistent with the        
  formula                                                                  
  for symmetric keys: N(N-1)/2 where N is the number of users needing to    
  communicate.  In this case the secret key is only counted once even if    
  it's                                                                      
  shared between users.                                                    
                                                                            
                                                                            
  Here's another question that has me puzzled:                              
                                                                            
  Which cryptographic system can be used for integrity, authenticity and    
  non-repudiation?                                                          
                                                                            
  A. Asymmetric encryption                                                  
  B. Symmetric  encryption                                                  
  C. Hashing                                                                
  D. None of the above                                                      
                                                                            
  The answers states A. Asymmetric.  Shouldn't the answer be D. None of the 
  above because Hashing is needed for integrity?                            
                                                                            
  Your thoughts will be much appreciated.                                  
                                                                            
                                                                            
  Tom Witwicki, CIPP                                                        
  Director, Information Security                                            
  Hannaford Bros. Co.                                                      
  207-885-2073                                                              
                                                                            
  Join me on Linkedin!                                                      
  http://www.linkedin.com/in/tomwitwicki                                    
                                                                            
                                                                            
                                                                            
                                                                            
                                                                            
                                                                            
                                                                            
  ------------------------------                                            
                                                                            
  Message: 2                                                                
  Date: Mon, 18 Jan 2010 21:47:45 +0000                                    
  From: "Mark Price" <prinext at gmail.com>                                    
  To: "The CISSP Study Mailing list" <cisspstudy at cccure.org>                
  Subject: Re: [Cisspstudy] New to CISSP Cert                              
  Message-ID:                                                              
      <                                                                    
  1180962559-1263851266-cardhu_decombobulator_blackberry.rim.net-147941822- 
  @bda153.bisx.prod.on.blackberry>                                          
                                                                            
  Content-Type: text/plain                                                  
                                                                            
  I have heard each edition is an update of the previous plus more of the  
  latest technology and or standards.                                      
  I have the 4th and the DVD set, they plus cccure.org worked for me.      
  V/r,                                                                      
                                                                            
  Mark Price                                                                
  PRINEXT                                                                  
  c:240-743-7654                                                            
  mprice at prinext.com                                                        
  www.prinext.com                                                          
                                                                            
  -----Original Message-----                                                
  From: Cert Prep <bugtraq.mailbox at gmail.com>                              
  Date: Mon, 18 Jan 2010 13:22:40                                          
  To: The CISSP Study Mailing list<cisspstudy at cccure.org>                  
  Subject: Re: [Cisspstudy] New to CISSP Cert                              
                                                                            
  Thanks Jeronimo. I will listen to it.                                    
                                                                            
  I have Shon Harris Second Edition which I bought many years back. I      
  have heard that 5th edition is about to come. Is it ok to prepare from    
  second edition until 5th edition is out? Does anybody know the            
  differences between 2nd and 4th? I am sure there will be many but are    
  those drastic to the extent that I will have to revise the stuff,        
  which I have already gone through using second edition, from 5th          
  edition once it is published?                                            
                                                                            
  Any help would be appreciated.                                            
                                                                            
  Thanks.                                                                  
  Adam                                                                      
                                                                            
  On Mon, Jan 18, 2010 at 12:51 PM, Jeronimo Zucco <jczucco at gmail.com>      
  wrote:                                                                    
  > 2010/1/18 Cert Prep <bugtraq.mailbox at gmail.com>:                        
  >> Hi Folks,                                                              
  >>                                                                        
  >> I am planning to prepare for CISSP Cert and would like to know which  
  >> book or material is best for the preparations.                        
  >                                                                        
  >                                                                        
  > http://www.cccure.org/flash/intro/player.html                          
  >                                                                        
  >                                                                        
  >                                                                        
  > --                                                                      
  > Jeronimo Zucco                                                          
  > http://jczucco.blogspot.com                                            
  >                                                                        
  > _______________________________________________                        
  > cisspstudy mailing list                                                
  > cisspstudy at cccure.org                                                  
  > http://cccure.org/mailman/listinfo/cisspstudy_cccure.org                
  >                                                                        
                                                                            
  _______________________________________________                          
  cisspstudy mailing list                                                  
  cisspstudy at cccure.org                                                    
  http://cccure.org/mailman/listinfo/cisspstudy_cccure.org                  
                                                                            
  ------------------------------                                            
                                                                            
  Message: 3                                                                
  Date: Tue, 19 Jan 2010 20:05:00 +0800                                    
  From: jack wang <windjie at gmail.com>                                      
  To: The CISSP Study Mailing list <cisspstudy at cccure.org>                  
  Subject: Re: [Cisspstudy] New to CISSP Cert                              
  Message-ID:                                                              
      <3c43566f1001190405t2bfd204as4a953dd160a5b92b at mail.gmail.com>        
  Content-Type: text/plain; charset="iso-8859-1"                            
                                                                            
  Shon Harris Second Edition,plus www.cccure.org,they are enough            
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  ------------------------------                                            
                                                                            
  Message: 4                                                                
  Date: Tue, 19 Jan 2010 10:34:19 -0200                                    
  From: Jeronimo Zucco <jczucco at gmail.com>                                  
  To: The CISSP Study Mailing list <cisspstudy at cccure.org>                  
  Subject: Re: [Cisspstudy] New to CISSP Cert                              
  Message-ID:                                                              
      <2d6b298c1001190434i6f1eb72ct1157b63b80fe9301 at mail.gmail.com>        
  Content-Type: text/plain; charset=ISO-8859-1                              
                                                                            
  All-in_one edition 5:                                                    
                                                                            
  http://www.amazon.com/CISSP-All-One-Guide-Fifth/dp/0071602178/ref=sr_1_2? 
  ie=UTF8&s=books&qid=1263898897&sr=8-2                                    
                                                                            
  I always recommend the last edition, because of updates and              
  corretions. Or you can read all erratas for your edition.                
                                                                            
  2010/1/19 jack wang <windjie at gmail.com>:                                  
  > ?Shon Harris Second Edition,plus www.cccure.org,they are enough        
  >                                                                        
                                                                            
                                                                            
  --                                                                        
  Jeronimo Zucco                                                            
  http://jczucco.blogspot.com                                              
                                                                            
                                                                            
                                                                            
  ------------------------------                                            
                                                                            
  _______________________________________________                          
  cisspstudy mailing list                                                  
  cisspstudy at cccure.org                                                    
  http://cccure.org/mailman/listinfo/cisspstudy_cccure.org                  
                                                                            
                                                                            
  End of cisspstudy Digest, Vol 19, Issue 16                                
  ******************************************                                
                                                                            





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