Lpc2000

jayasooriah wrote:

>Pleae let me clarify.  I am seeking affirmative answers to the two
>questions below so as to assure client that code in the LPC parts
>(with CRP enabled) is secure.
>
>According to the Product Overview Edition 08 2005 provide by Philips,
>all of the LPC2100 series parts less 2194 is marked "Y" for Parallel
>Programming (PP) feature column.
>
>Client was told PP can read and program on-chip flash.  Philips (Jim
>E) by email has advised me that I could use PP to re-load the on-chip
>flash for LPC2105 parts that my students manage to kill just by bad
>coding.
>
>Client wants Philips to confirm that if the device is secured using
>CRP, then PP cannot be used to access the on-chip flash.
>
>  
>

Good grief!  The last time I had a "secure" part with an external bus, I 
proved that I could defeat the "security" by enabling the external ROM 
and then reading the internal ROM.  There was a problem with that part.

Have you done nothing but 'read'?  Come on now, try it out, see if you 
can break it.  Spend some money, get a parallel programming setup, can 
you break it??

Sheesh

TomW


>Your say:
>  
>
>>A parallel programmer will not be able to read
>>or program a secured device.
>>    
>>
>
>Q1: Can I tell client Philips has confirmed CRP is not voided by PP?
>
>I am curious, what happens to a part when is CRP enabled, and if there
>is no way to recover the part at all.
>
>In the same Product Overview document referred to above, all of the
>LPC2200 series parts that have external memory interface have a "-"
>against the PP feature column.  If it was a "N", I would tell client
>this means these devices do not support parallel programming.  I am
>not sure what the "-" means.
>
>If these devices cannot be parallel programming, how does the on-chip
>flash gets loaded the first time, or after it has been corrupted?
>
>Client was told that these parts are loaded (first time) by forcing
>them to boot from external memory by pull downs on specific pins
>during reset.
>
>Q2: Would Philips confirm such methods cannot be used to defeat CRP?
>
>I am curious how Philips loads the flash first time for these parts.
>
>You make the statement:
>
>  
>
>>Oh yes, you, the user is always able to "undo" your
>>security while running IAP but how would a "spy" be 
>>ever able to run IAP (In application programming)
>>    
>>
>
>If the user can "undo" CRP, you must assume the "spy" can.
>
>Security by obscurity (which attempts to use secrecy of design,
>implementation, etc) to ensure security is not acceptable to the client.
>
>As an example, Philips "secured" boot loader sector by keeping the
>programing algorithms a secret.  My students killed two of my 2105
>boards by accident.  I could not tell them what they should not do
>because I did not know the programming algorithm.
>
>I am sure there are many who have worked out the algorithm as I now
>have.  How long do you think it takes for one of these persons to
>publish the algorithm on the net, assuming this has yet to happen?
>
>Jaya
>
>--- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@y...> wrote:
>  
>
>>Jaya,
>>
>>I am truely sorry but I do not understand your point. A parallel 
>>programmer will not be able to read or program a secured device. A 
>>microcontroller that executes an external program can not be secured 
>>because the external code can always be compromised. Booting from 
>>external is not possible once the device is secured and programmed 
>>to boot internally.
>>
>>Did I miss something?  Oh yes, you, the user is always able 
>>to "undo" your security while running IAP but how would a "spy" be 
>>ever able to run IAP (In application programming). The devices you 
>>mentioned also leave the option to reenable JTAG in your program, 
>>again, chicken and egg, as the spy will not be able to alter your 
>>program how can he enable JTAG. 
>>
>>Philips Apps
>>    
>>
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>Yahoo! Groups Links
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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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