Re: gEDA-user: encrytped models on gnucap or ngspice

[Rick Collins <gnuarm.2007@xxxxxxxxx>]

At 09:49 AM 4/25/2008, you wrote:
>>Can either of these simulators handle an encrytped model?  I have
>>some from fairchild that are hspice format, using ".prot FREELIB" ,
>>which is encrypted.
>
>The short answer is no.
>
>To expound on this answer, if the HSpice folks were to release details
>about their encryption algorithm, then we could implement reading of
>encrypted models in ngspice/gnucap.  However, then you'd have no
>incentive to pay $$$ to purchase HSpice.  Therefore, I doubt that the
>owners of HSpice (is it Cadence these days?) will every release the
>details of their encryption.
>
>What you could do is approach Fairchild and ask them for an
>unencrypted version of their model.  They have no reason to disappoint
>a customer simply to keep the HSpice encryption algorthm sekrit, so
>unless they have a reason to hide their own IP in their model, I don't
>see why they would want to keep it encrypted.

Actually, they *do* have an incentive to keep their models secret, to 
protect *their* IP.

I recently was working on an opamp design that required a lot from 
the available parts.  To try to make sure I was building a design 
that worked, I simulated it.  When I asked why so many of the high 
end parts had no model available, many people told me that they don't 
release models for their more competitive parts to prevent the 
competition from reverse engineering the parts based on the 
models.  That is also the reason that the released models typically 
are a bit on the "dumb" side.  They are different from the models 
used internally, again to protect their IP.

I don't recall if Fairchild has a simulator that they release.  I 
know that some other vendors do just that, they release protected 
models that will only work with their version of the simulator.  I 
seem to recall that Fairchild does this, but I'm not sure.



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