Crate oxicrypto_rand 

Pure Rust CSPRNG for the OxiCrypto stack.

Provides OxiRng, a ChaCha20-based CSPRNG seeded from the OS via getrandom.

Fork Safety

On Unix platforms, OxiRng tracks the process PID and automatically reseeds after a fork() to prevent parent/child CSPRNG state sharing.

Thread-Local RNG

Use with_thread_rng (available with the std feature) for a convenient per-thread RNG (lazily initialized, no explicit RNG management required).

ChaCha Variants

OxiRng8 and OxiRng12 provide ChaCha8 and ChaCha12-based CSPRNGs for higher throughput when the full 20-round version is not required.

Entropy Health Check

check_entropy performs a basic OS-entropy smoke test (two independent draws must be non-zero and differ). This is not a NIST SP 800-90B test.

Structs

OxiRng

A ChaCha20 CSPRNG seeded from the OS random source.

OxiRng8

A ChaCha8 CSPRNG seeded from the OS random source.

OxiRng12

A ChaCha12 CSPRNG seeded from the OS random source.

ReseedingRng

A OxiRng wrapper that automatically reseeds from OS entropy after generating a configurable number of bytes (default: 1 MiB).

Functions

check_entropy

Perform a basic OS-entropy smoke test.

random_bool

Generate a random bool with the given probability of being true.

random_bool_with_rng

Generate a random bool using an existing RNG, with the given probability of being true.

random_bytes

Allocate and fill a Vec<u8> with len cryptographically secure random bytes.

random_nonce

Generate a random nonce of N bytes for use with AEAD algorithms.

random_range

Generate a random integer in [min, max) using rejection sampling to eliminate modulo bias.

random_range_to

Generate a random integer in [0, max) using rejection sampling.

random_range_unbiased

Generate a random integer in [min, max) using an existing RNG, with rejection sampling to eliminate modulo bias.

random_u32

Generate a cryptographically secure random u32.

random_u64

Generate a cryptographically secure random u64.

random_u128

Generate a cryptographically secure random u128.

reseed

Perform a manual reseed of the given OxiRng from OS entropy.

shuffle

Cryptographically secure in-place Fisher-Yates shuffle.

weighted_choice

Sample an index from a weighted distribution.

weighted_choice_with_rng

Sample an index from a weighted distribution using an existing RNG.