Better seeds than time(0)?

Question

I understand that time(0) is commonly using for seeding random number generators and that it only becomes a problem when the program is being run more than once per second.

Answer 1

You will need an alternative/secondary source of entropy. Depending on how much entropy you want to use, you can calculate a hash of any of the following inputs and use it as a seed for your final generator:

• declare an unintialized random size char array on the stack
• allocate a random bytes of memory
• ask the user to move the mouse
• ask the user to put random CD in the CD drive and read random bytes at random location from the first track
• open the user's microphone or camera, collect random number of seconds of input, calculate a hash and seed
• Windows: use CryptGenRandom to get a buffer of cryptographically random bytes
• Unix: as others mentioned, read from /dev/random