Certified True Randomizers (CTR) is a free, open-source app that provides a source of true randomness. It was developed with the aim of providing a practical way to generate random numbers that can be used in various applications. 

In order to achieve this goal, the app combines two different sources of randomness: one is the atmospheric noise, which is an unpredictable and random noise that is very difficult to predict, and the other is the machine-generated randomness, which is a random number that can be generated by a computer program.

As a result, the app is capable of providing numbers that are very close to the true randomness. It can also be used to create random passwords, keys, and cards.