# True Random Number Service

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## Information Entropy Statistics

RANDOM.ORG generates true randomness via atmospheric noise. This page shows the information entropy statistics.

Showing graphs from

(Each graph is from a different radio. Click on the graphs to enlarge them.)

The graphs on this page show the level of information entropy in the randomness generated by RANDOM.ORG. Information entropy gives an indication of the amount of information in the data. The more information there is in each bit of information, the more difficult it is to predict what the next bit will be based on the bits you have already seen. The graphs on this page shows the entropy level in the RANDOM.ORG data as a percentage of the theoretical maximum.

Information entropy is often used as a preliminary test for randomness. Generally speaking, random data will have a high level of information entropy, and a low level of information entropy is a good indicator that the data isn't random. (A low level of entropy isn't definitive proof that the data isn't random, but it means you should be suspcious and submit the generator to further tests.)

However, the converse relation doesn't hold, meaning a high degree of information entropy is no guarantee of randomness. For example, a compressed file (e.g., a ZIP file) has a high level of information entropy, but is in fact highly structured, and it will fail many other tests for randomness. Hence, you have to be a little careful using information entropy as a metric for randomness. To get meaningful results, you really need to combine it with other tests.

Each graph shows how a given radio performed on a particular day. New graphs are generated automatically shortly after midnight (UTC) every day. Each radio has its own name (e.g., copenhagen-hw0), and each graph is labelled with the name of the radio to which it belongs. Not all radios are active on all days.