memfrob - frobnicate (encrypt) a memory area
#define _GNU_SOURCE /* See feature_test_macros(7) */
void *memfrob(void *s, size_t n);
The memfrob() function encrypts the first n bytes of the memory
area s by exclusive-ORing each character with the number 42.
The effect can be reversed by using memfrob() on the encrypted
Note that this function is not a proper encryption routine as
the XOR constant is fixed, and is suitable only for hiding