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:

Arduino SAMD Cavium NITROX Espressif ESP32-WROOM-32 Infineon Aurix TC3xx Infineon/Cypress PSoC Intel SGX Intel RDRAND Maxim MAX326xx Maxim MAXQ10xx Microchip/Atmel ATECC608 Microchip PIC32MZ Nordic nRF5x NXP i.MX6 CAAM NXP i.MX7 CAAM NXP i.MX RT1060 NXP Kinetis and KSDK Renesas RA6M4 Renesas RZ/N2L Silicon Labs SE Telit M2MB Whitewood Quantum RNG Windows CryptGenRandom STM32C0xx STM32L0xx STM32G0xx STM32F0xx STM32L1xx STM32F2xx STM32F3xx STM32L4xx STM32G4xx STM32F4xx STM32WBxx STM32WLxx STM32F5xx STM32U5xx STM32L5xx STM32F7xx STM32H7xx STM32H5xx Xilinx Versal

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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