<p>The use of random numbers, or at least sequences with particular stochastic properties, is crucial in several disciplines. The literature classifies these sequences into two main classes: true random numbers and pseudorandom numbers. The process of generating each category requires different methodologies adapted to their intrinsic properties. This study focuses on the generation of true random numbers, specifically by exploiting free-running oscillators as a source of entropy. A comprehensive analysis of different generation techniques is presented, with special emphasis on the validation and verification procedures used to assess the statistical robustness and unpredictability of the generated sequences.</p>