There is something I am not entirely clear about.
If you have a library published under GPL 2 and include it in your new program, can you publish the new application with GPL 3 or it falls in the category of modified code thus it needs to be published under GPL 2 also?
https://www.gnu.org/licenses/gpl-faq.html#v2v3Compatibility
edit: iirc if you don't directly link to it you can get away with using it anyway (e.g. using dlopen/dlsym)
As swick said it depends on how you use the library also its its GPLv2 or GPLv2 or later.
Libraries (i think) would normally be LGPL which allows linking and using a different license, qt for example is GPLv3/LGPL GTK+ is LGPL, which allows them to be used in any other application as a library.
Well I have the Misty algorithm which is published under GPL 2 (not 2 or greater). It is included into an otherwise original code. So in what you are describing the new program should be published with GPL 2 as GPL3 is incompatible? Correct?
Got a link?
OK. So the author is currently breaking the GPL license. he has used imdcode.c which is GPLv3 and incompatible with the misty code he is using licensed under GPLv2, but thats up to them to fix, i doubt anyone has even noticed till now. You could always ask them to re-license it all in GPLv3
As for MISTY. You could write it yourself, its not very big the algorithm is here http://tools.ietf.org/html/rfc2994
The question to ask (which I have the suspicious feeling the author of the code you linked to hasn't considered) is that MISTY may or may not be allowed to be used in commercial software as it does or did carry patents which may or may not still be enforced.
Its fine I have control over it, by the authors consent as he asked for advice. The original author of Misty from 98 I cannot find but I will have the others publish everything with the GPLv2. The code is not commercial but academic. The company is a non-profit University spin-off thus it should not be a problem.
Oh and of course thanks for the advice guys.
The original author isn't a problem as it was originally a spec as published in RFC. Unless of course the code for misty was taken from a sample code the original authors made and not created from scratch, in which case the misty GPLv2 takes priority unless you can find all original authors of the code to have it re-licensed.
For your purposes I imagine GPLv2 is perfectly fine.