To quench your curiosity, this is all related to RSA..
Also, Duck, I have found that the Intel Compiler supports 128-bit integers natively. Also, very few newbie books (you seem like your new to C++) say anything about __int64, because it isn't a standard in C++...It was first a VC++ thing, but now many other compilers support some sort of 64-bit integer. The Intel Compiler has i64,and i128...or something similar, but it has both 64-bit an 128-bit.

I'm still relatively new to C++ as well. I've written quite a few useful apps, but I learn everything on the fly, so I'm still very shaky on classes, and have no clue how to overload and all that good stuff. I was looking for an "easy way out", because my friend has begun to write his own integer class that will accept up to 4096-bit integers...yes, he is, in fact, insane.

A_T