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Re: gEDA-user: Free Dog meeting report: Notes on the topics we discussed



On Sep 21, 2005, at 10:12 PM, Ales Hvezda wrote:
However, what if libgeda stored a cryptographic signature/hash of
the symbol file contents along with the filename in the schematics?
The signature can be something along the lines of an md5sum string (maybe
not so long, but long to uniquely identify the contents). When a symbol
is loaded from disk, the signatures are compared and if they don't match,
a warning is issued. Sorta like the existing symversion= mechanism,
but now it will not be possible for symbol changes to escape notice
from the designers. And should there be a valid symbol change, then the
component is simply updated using Edit/Update Component.


	Now back to the original problem: two symbols identically named
symbols will most likely not have identical signatures/hashes and it
would be impossible for the wrong symbol to be silently netlisted.

Comments on this idea?

I think this is an excellent idea. I strongly suggest, however, embedding a string to identify the hash type along with the hash. Perhaps something like this:


symhash=MD5;0xb05e8543abc3ec394022e93da3f594fd

This approach would allow the software to unambiguously use newer hash algorithms as they become available, while maintaining compatibility with older algorithms.

           -Dave

--
Dave McGuire "You'll have to be a lot more specific than 'that
Cape Coral, FL girl last night.'" -Ted McFadden