Only the latest version of the library is supported with security updates.

This library is designed for embedded systems, which often lack a Cryptographically Secure Pseudorandom Number Generator (CSPRNG).

• ESP32 / ESP8266: Uses hardware TRNG. Highly secure, provided the radio (Wi-Fi/BT) is enabled or the bootloader RNG is active. (Note for ESP8266: If the device operates with Wi-Fi disabled, e.g., in Modem/Deep Sleep, use setRandomSource() or mixEntropy() as os_get_random() loses entropy quality without the active radio).
• RP2040: Uses the Ring Oscillator (ROSC) for entropy.
• STM32: WARNING. The default implementation uses the Arduino LCG (random()) XOR-ed with the 96-bit hardware UID and SysTick jitter. This guarantees per-device uniqueness but is NOT cryptographically secure. For production, call randomSeed() in your setup, or inject a hardware RNG via setRandomSource().
• AVR (Arduino Uno/Nano/Mega): WARNING. AVR chips do not have hardware RNG. The library falls back to ADC noise and clock jitter. This is NOT cryptographically secure. For production AVR environments, you MUST inject a custom RNG using setRandomSource() or use mixEntropy() with a unique device ID.

• ESP32: Fully thread-safe using portMUX.
• RP2040: Fully thread-safe using hardware spinlocks (requires Earle Philhower core).
• STM32 / Custom FreeRTOS: You can inject custom thread-safety locks at runtime using uuid.setLockCallbacks(). For example, in FreeRTOS: uuid.setLockCallbacks([](){ taskENTER_CRITICAL(); }, [](){ taskEXIT_CRITICAL(); });.

If you discover a security vulnerability, please use the GitHub Private Security Advisories feature to report it confidentially, or contact the maintainer directly.