Re: Algorithms to generate permutations

From: BRG (brg_at_nowhere.org)
Date: 08/04/05 

Date: Thu, 04 Aug 2005 12:07:51 +0100

Crypto@S.M.S wrote:

> BRG wrote:
>
>> Crypto@S.M.S wrote:
>>
>> [snip]
>>
>>>> There are a few (typically specialist) applications where this extra
>>>> protection can be valuable, an example being situations where
>>>> protection
>>>> is needed for several decades or more.
>>>
>>>
>>> CryptoSMS is one such "specialist" application.
>>
>> I took a quick look at your web pages and I don't see anything to
>> suggest that CryptoSMS is a specialist application. It is a general
>> purpose product that attempts to add security to SMS messaging.
>
> It is "specialist" in that it only runs on PocketPCs and SmartPhones.
>
>> Quite apart from the security problems raised by others, it lacks
>> important characteristics that I would expect to see in a specialist
>> high security product intended for such use.
>>
> What are these "important characteristics"?

There are quite a few things that are absent but two I will mention are:

(a) a design document including a threat model, a security design
specification and an analysis that shows how the design successfuly
counters the threats described in the model;

(b) an independent validation of the design and implementation to
national or international security assurance standards such as those set
out here:

http://www.cesg.gov.uk/site/iacs/index.cfm?menuSelected=1&displayPage=13

The essential difference between general and specialist information
security products is that the latter provide a high level of confidence
in the security claims made by their suppliers because these claims have
been independently scrutinised and verified to recognised standards of
security assurance.

Designs that are going to be independently verified in this way are very
costly to produce and very costly to validate. In consequence the
resulting products are extremely expensive and this makes them
specialist in nature.

In consequence most of us don't bother and simply accept that our
security will be measured in 10's of bits rather than 100's if we are
ever unfortunate enough to face a determined and well resourced
attacker. Fortunately the protection provided by the 'needle in a
haystack' phenomenon can come to our rescue provided that we take
_other_ (i.e. non-cryptographic) measures to protect ourselves.

Risible claims of 1000's of bits of cryptographic protection in software
products such as CryptoSMS serve only to discredit those who make them.

   Brian Gladman

Relevant Pages

  • Re: Security and EOL issues
    ... OS software resources are designed that reserved ram and disk space among other resources, to reflect what current hardware size is available. ... (There was a security patch a few years ago that could not be applied to NT4 as it required more resources then NT4 could provide. ... Installing air bags requires that the automobile manufacturer design, test, ... Computer Emergency Response Teams, and Digital Investigations. ...
    (Security-Basics)
  • Re: Security issue with MS Exchange and Windows 2003 Server
    ... My design peoples will not accept either accept our IT instruction until one ... there are security issue caused by the staffs but they hire me to patch ... >> I believe yoy are qualified to steer him in the RIGHT direction for MS Exchange Server AV ... >> He uses a web site and Bowseing to show protection. ...
    (microsoft.public.security.virus)
  • Re: Simplest OS for new ISA
    ... security design to try to handle future attacks. ... AT&T core OS was design back in 1969 and uses the ... To finalise the design of the simplest assembler, ... we can just jump to multi core ...
    (comp.arch)
  • Re: I need a system the U.S. government cannot hack
    ... By way of a further excuse, using words such as 'hack', 'government' or ... The security requirements are driven in part by the costs associated with ... The bulk of the cost of box and wire systems is in the infrastructure --> ... While I can, and will, and am trying, to move ahead with my own design, ...
    (microsoft.public.security)
  • Re: I need a system the U.S. government cannot hack
    ... By way of a further excuse, using words such as 'hack', 'government' or ... The security requirements are driven in part by the costs associated with ... The bulk of the cost of box and wire systems is in the infrastructure --> ... While I can, and will, and am trying, to move ahead with my own design, ...
    (microsoft.public.security)