Rsa, Miller Rabin, Prime Numbers, Algorithms, Cryptography.
between 1 and x can be approximated by So a random number between 1 and 1 billion has about a 5% chance of being prime. Not bad. But modern cryptosystems like RSA require choosing ridiculously large primes — about 150 digits long. If you pick a random number that is 150 digits long, you have about