True Random vs. Pseudorandom Number Generation

In the world of computing, “randomness” isn’t a one-size-fits-all concept. Whether you are developing a gaming app or securing a high-stakes cryptographic protocol, the type of Random Number Generator (RNG) you choose matters. The distinction boils down to one factor: reproducibility.

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Pseudorandom Number Generators (PRNGs)
A PRNG is a deterministic algorithm. It takes a starting point—called a seed—and applies a mathematical formula to produce a sequence of numbers that looks random.
- The Pro: They are incredibly fast, efficient, and require no special hardware.
- The Con: If an attacker discovers the seed and the algorithm, they can predict every subsequent number in the sequence.
- The Use Case: PRNGs are excellent for simulations or “stretching” high-quality entropy. Because True Random data is computationally “expensive” to harvest, developers often use a small amount of TRNG data as a seed for a cryptographically secure PRNG.
True Random Number Generators (TRNGs)
TRNGs don’t rely on math; they rely on physics. They capture “entropy” from unpredictable physical phenomena in the real world. Common sources include:
- Thermal Noise: Minute fluctuations in electronic circuits.
- Ring Oscillators: Jitter in high-frequency clock signals.
- Radioactive Decay: The unpredictable timing of atomic breakdown.
- Atmospheric Noise: Radio static caused by lightning and other natural events.
Because these physical processes are non-deterministic, the resulting numbers are truly unpredictable, even if the observer knows exactly how the hardware works.

Implementation with wolfSSL
Choosing between speed and security doesn’t have to be a compromise. At wolfSSL, we provide tools to help you implement the right level of entropy for your environment:

wolfEntropySP800-90B ESV validation. It is designed to operate seamlessly with wolfCrypt, our high-performance crypto engine.
Hardware Integration: Most modern big metal processors and high-end microcontrollers feature built-in TRNG sources. wolfCrypt can leverage these directly as a primary random source or use them to seed an internal PRNG for high-speed cryptographic operations. wolfCrypt has support for TRNGs such as:

Whether you need a validated software solution or hardware-backed entropy, we ensure your “random” numbers stay exactly that: random.

If you have any questions or comments, contact us at wolfSSL by emailing facts@wolfSSL.com or calling us at +1 425 245 8247.

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