nanosha256 - v1.0.0

A minimal, high-performance, security-hardened single-header C library for SHA-256.

Features

• Pure C: Requires only stdint.h and string.h.
• Zero Allocation: No malloc is used.
• Performance: Fully unrolled compression rounds and inlined macros.
• Endianness Optimized: Fast byte-swapping for little-endian architectures.

Usage

Simply include nanosha256.h in your project.

#include "nanosha256.h"

// Streaming API
SHA256_CTX ctx;
uint8_t hash[32];
SHA256_Init(&ctx);
SHA256_Update(&ctx, "abc", 3);
SHA256_Final(hash, &ctx);

// State-based primitive API (requested)
uint32_t state[8];
sha256_init(state);
sha256_transform(state, some_64_byte_block);
sha256_final(state, hash, total_bits);

Testing

To run the included tests:

make test

License

MIT License (2026-present oopsio)