Good point Jac. Indeed I do allow others to use it, but the original copyright holders should too 
. I'm not a lawyer (do not want to be either) but found out that it is less simple than I thought. If anybody has experience with this I would like his/her input.
The original copyrights are Eclipse for IBM code and GPL v3 for the encryption files distributed by Ideetron. I therefore have for the moment put a reference to GPL3 in those 4 files. Both GPL3 and Eclipse could be used for distribution of code and re-use.
So multi-licensing may work but for such a small project not nice, and Eclipse and GPL v3 are not always going together well. For my code I will use Eclipse for the changed parts in various IBM files most importantly for the changed aes.cpp file which is the easiest.
I have contacted Ideetron to hear their view on this.
Maarten
PS. Maybe I should have selected an AES library with Eclipse licensing, or maybe moving the encryption part to a different directory .