Sometimes generation process of secure key can be a little bit problematic because of not enough random bytes available in software pseudo-random device. You could see a message like this (for PGP key gen):
**We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. Not enough random bytes available. Please do some other work to give the OS a chance to collect more entropy! (Need 210 more bytes)**