On 1/3/2014 4:25 PM, Timothy Murphy wrote: > Shannon entropy only makes sense when applied to a random variable. > It cannot be applied to a single string, as in this case. the seed of a algorithm like /dev/urandom is not a single variable, its a big array of variables. these have to be created with sufficiently random external events to achieve a reasonable level of entropy, and if you continue to generate pseudo-random-numbers from this when those random external events aren't ongoing at a high enough rate relative to your requirements for new random numbers, eventually the 'entropy' runs out, and the sequence becomes increasingly predictable. -- john r pierce 37N 122W somewhere on the middle of the left coast