None Unix swapfile security issues...

I'm working on a unix application where I want to store a key in memory and don't want it to get written out to a swap file. If the key is in any of the application's memory pages, it could be swapped out at any time, and potentially left in the swap file when the computer is turned off. But, what if the program creates a pipe() and writes the key into it, then reads the key out when necessary? A pipe has a 4K buffer, but that buffer is in the kernel's memory, not in the application's pages. Could a kernel buffer get written out to a swapfile?