Slicing in userland In OpenBSD userland, the primary perturber of the stream is the malloc(3) subsystem 'otto-malloc', this is no longer 'phk malloc' malloc() and free() call arc4random() very often to make decisions about behaviour for padding, recycling, and page layout. This cuts the libc random stream up in (recursively) perturbed fashion. DNS and ld.so also take slices of random data