New tutorial in the works
Sorry about the long layoff - I have been incredibly busy with my class and job interviews over the last few weeks. I just wanted to let you guys know that I have another tutorial in the works for wireless security using the ARC4 stream cipher algorithm. For those of you that aren't familiar with ARC4, it's a hack of the RC4 algorithm developed by the RSA. RC4 is used very widely in many crpytostreams, including SSL and WEP. I'm hoping to have it done and written up in a week or two. If all goes well, I'll have implementations for both the LPC2148 and PIC18F452 in conjunction with the nRF24L01 and ARC4.
Edit: The tutorial has been completed and is linked at this post toward the bottom: http://www.diyembedded.com/2007/08/arc4-tutorials-posted.html