Bitwise solution?

I'm wondering how I can do the following (if it is possible at all): I have 2 values. The first is a constant while the second is not. The second value, in this case, is a unix time stamp and as such will change every time it is set, down to the second. I need to somehow merge the two values so that the new, merged value would be as (semi) unique as the timestamp value. I was thinking I could do something like this: ( var1 & var2 ) But that generates an identical value every time. Is there a way I can do this? And no, I cannot just use the timestamp value. :P And microtime() isn't really an option either. :( Any help at all would be greatly appreciated! :) Chris