[A83] Re: apps


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[A83] Re: apps



Ah,
ofcourse, I forgot about the calc-ID's...


Dan Englender wrote:

>> To my knowledge, it tells the calc to allow apps that are signed with
>> the developer signature.
> 
> .....Applications are signed with a key for a specific ID.  For example, the
> shareware/freeware key (which is available only to TI) signs applications
> for the 0104 ID (my personal ID is 9F04).  All calculators can load
> applications signed for the 0104 ID.  When you sign an application with a
> key, it creates some sort of data (I'll call it a checksum) which is used by
> the calculator to validate the application.
> When you load the application onto the calculator, it's checked against the
> certificates you have loaded onto your calculator, and if you don't have the
> required certificate, the calculator rejects the application.
> 
>> But hey, if someone were to make his developer certificate and signing
>> available to anyone,
>> we could simply sign apps with that signature, and put the specific
>> developer signature with it.
> 
> .....This would not work.  The problem is with the developer certificate.
> Certificates are also validated when sent to the calculator.  This time,
> it's validated based on your serial number.  Of course, there's encryption
> involved, so you can't just open up the certificate file and change the
> numbers.  So if you have the same serial number as someone else (which
> obviously you don't), you could load their certificates, and thus their
> applications.  Otherwise, you're stuck.
> 
>> But, since we know TI longer than today, they 'll probably have included
>> some statement in some license, stating it to be "illegal" to distribute
>> one's developer certificate and signings...
> 
> .....As far as I know, there is no such clause in any license.  Just having a
> key and certificate doesn't help you at all.  Just like if someone purchases
> an application from TI, they can send the application to you and you wont be
> able to use it.
> 
> -Dan Englender
> 
> ----- Original Message -----
> 
>> To my knowledge, it tells the calc to allow apps that are signed with
>> the developer signature.
>> 
>> But hey, if someone were to make his developer certificate and signing
>> available to anyone,
>> we could simply sign apps with that signature, and put the specific
>> developer signature with it.
>> 
>> But, since we know TI longer than today, they 'll probably have included
>> some statement in some license, stating it to be "illegal" to distribute
>> one's developer certificate and signings...
>> 
>> Someone, please verify this!!
>> 
>> ...and think of some legal trick to circumvent this. (e.g. making all
>> apps made with that certificate "beta stage" (officially, that is) in
>> case they stated that the dev certif. can only be used for beta testing
>> apps...)
>> 
>> --Peter Martijn
>> 
>> Gavin Olson wrote:
>> 
>>>> You send them the unsigned application, and they sign it.  You can make
>>>> applications yourself, and run them on your calc if you get a developer
>>>> certificate for your calc from TI.  Or use their Flash Simulator, or
>>> 
> the
> 
>>>> upcoming VTI.  I wrote a plugin for Assembly Studio 8x to make
>>> 
> applications
> 
>>>> (.hex files).
>>> 
>>> 
>>> What does this developer certificate on the calc do to make unsigned
>> 
> apps
> 
>>> work?
>>> 
>>> 
>>> 
>>> 
>>> 





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