char *copyBootHash(void) {
    unsigned char buf[1024];
    uint32_t length = 1024;
    io_registry_entry_t chosen = IORegistryEntryFromPath(kIOMasterPortDefault, "IODeviceTree:/chosen");

    if (!MACH_PORT_VALID(chosen)) {
        printf("Unable to get IODeviceTree:/chosen port\n");
        return NULL;
    }

    kern_return_t ret = IORegistryEntryGetProperty(chosen, "boot-manifest-hash", (void*)buf, &length);

    IOObjectRelease(chosen);

    if (ret != ERR_SUCCESS) {
        printf("Unable to read boot-manifest-hash\n");
        return NULL;
    }

    // Make a hex string out of the hash
    char manifestHash[length*2+1];
    bzero(manifestHash, sizeof(manifestHash));

    int i;
    for (i=0; i<length; i++) {
        sprintf(manifestHash+i*2, "%02X", buf[i]);
    }

    printf("Hash: %s\n", manifestHash);
    return strdup(manifestHash);
}