Re: [CISSP-D] Do Symmetric Key Algorithms provide authenticity?

Date sent:              Sat, 08 Jul 2006 19:17:33 +0000
From:                   Rabbani <smrabbani@yahoo.com>

> Symmetric key algorithms can provide confidentiality but not 
> authentication, says Shon Harris in her book, All In One CISSP exam 
> guide (Page # 680, Quick Tips, Cryptography).
>
> Whereas the SYBEX book, CISSP Study guide, by James, Ed and Mike 
> says 'Authentication can be achieved by both symmetric and asymmetric 
> cryptosystems.

Limited authentication, as in detection of changes by errors or an adversary, 
can 
be detected by both, but only if both parties to the communication are honest.  
Non-repudiation can only be achieved by asymmetric.

(And, of course, there are always provisos like "man-in-the-middle".)

======================  (quote inserted randomly by Pegasus Mailer)
rslade@vcn.bc.ca     slade@victoria.tc.ca     rslade@computercrime.org
Computers are useless. They can only give you answers.
                                                     - Pablo Picasso
Dictionary of Information Security  www.syngress.com/catalog/?pid=4150
http://victoria.tc.ca/techrev/rms.htm


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