[erniebilko]

There are 2 components required to ensure a good shuffle:

1. Unpredictability of the seed number which is used in an algorithm to obtain a number in the required range.

2. An even distribution of output so that all numbers in the required range are equally likely to be obtained from the algorithm.

In the early days of Internet poker, Planet Poker's shuffle was exposed as non-random and a team of mathematicians easily found the seed number which was based on time of day. Finding the seed and knowing the algorithm allowed them to see all cards in every player's hand. Now, the seed number is derived form truly random input using a combination of user mouse movements and thermal noise.

The rest of the description is an explanation of how they ensure that the distribution of output is even, so that the results are not skewed to favor any part of the range.