Recently, a problem was discovered in the pseudo-random number generator which Google Chrome and Node.js's V8 JavaScript engine uses and depends on. The problem was that a pattern was discovered in the series of numbers which the RNG algorithm produced, meaning you could guess the "random" outcome at a probability higher than chance, giving you an advantage - whether the application is breaking encryption or passwords or beating games of chance.
Edward Snowden, who had worked for the CIA, warned of problems or backdoors in hardware random number generators which many computers...