mackron / cryptorand Goto Github PK

This uses the operating system's random number generation. If you're looking for a CSPRNG from scratch you'll need to look elsewhere.

Supported generation methods are Win32's BCryptGenRandom() with CryptGenRandom() as a fallback. On platforms that support /dev/urandom, that will be used. OpenBSD will use arc4random().

There is no need to link to anything with this library. You can use CRYPTORAND_IMPLEMENTATION to define the implementation section, or you can use cryptorand.c if you prefer a traditional header/source pair.

There's only three functions, all of which should be self explanatory and easy to figure out:

cryptorand_result cryptorand_init(cryptorand* pRNG);
void cryptorand_uninit(cryptorand* pRNG);
cryptorand_result cryptorand_generate(cryptorand* pRNG, void* pBufferOut, size_t byteCount);

Call cryptorand_init() to initialize the random number generator. On Windows, this is where libraries are linked at runtime so avoid calling this in high performance scenarios. It's best to just create one instance and then read from it multiple times.

To generate random bytes you need only call cryptorand_generate(). You just specify a pointer to a buffer that will receive the random data and the number of bytes you want. If this fails, the content of the buffer will be cleared to zero.

Uninitialize the random number generator with cryptorand_uninit().

Thread safety depends on the backend.