Tiny (as in, < 1000 LOC) SCrypt implementation, mostly based on https://github.com/technion/libscrypt.

The biggest difference between tinyscrypt and libscrypt is that the SCrypt-parameters for tinyscrypt have to be set at compile time. This saves two calls to malloc (making the library malloc-free, only requiring one mmap call).

This is a derivative work based on https://github.com/technion/libscrypt/, which itself is a derivative work based on the original implementation by Colin Percival (http://www.tarsnap.com/scrypt.html).

All original source code is licensed under the BSD License (see tinyscrypt.h header). My changes can be considered public domain.

Simply include tinyscrypt.c and tinyscrypt.h in your build. There are no external dependencies. Default parameters can be overwritten at compile time using the following cflags: -DTINYSCRYPT_N=XX -DTINYSCRYPT_R=X -DTINYSCRYPT_P=X.

Tinyscrypt can be compiled without libc if you provide your own implementations for memcpy, memcmp, memmove, and mmap. In this case compiling the library using -fno-stack-protector is required to not pull in libc dependencies.

#include <stdio.h>
#include "tinyscrypt.h"

int main() {
    int ret;
    const char* pw = "pw";
    const char* salt = "salt";
    uint8_t out[64];

    // ret: 0 = OK, !0 = Error
    // Password, Password-len, Salt, Salt-len, output buffer, buffer-len
    ret = tinyscrypt((const uint8_t*)pw, 2, (const uint8_t*)salt, 4, out, 64);

    if (ret != 0) {
        printf("Scrypt failed!\n");
        return 1;
    }

    // result is in `out`

    return 0;
}