Generate Wordpress salt

Question

I am in need of a function that automatically generates and returns salts for Wordpress wp-config.php (Don't link me to their API, I'm looking for offline solution).

Does Wordpress core has this function defined somewhere? If it doesn't, can these salts be generated randomly or are there any specific rules for creating them?

Edit: This is what I ended up with:

    $keys = array('AUTH_KEY', 'SECURE_AUTH_KEY', 'LOGGED_IN_KEY',
              'NONCE_KEY', 'AUTH_SALT', 'SECURE_AUTH_SALT', 'LOGGED_IN_SALT', 'NONCE_SALT');
    $salts = '';
    foreach ($keys as $key) {
        $salt = wp_generate_password(64, true, true);
        $spaces = str_repeat(' ',16 - strlen($key));
        $salts .= "define('{$key}',{$spaces}'{$salt}');\n";
    }

And the output is string:

define('AUTH_KEY',        'f@5^8(OyZLS%+~LNQ6,w(Zpn`3X#A}o4t2LQuqc=x4vn+ b}xYM>TlSwB`|E;}PA');
define('SECURE_AUTH_KEY', 'vEEF@-c_`VO!d{s)_Nv^uS,)eg9{;60.$nU370/9E1z}O#iu)wkPrw8sh[TqGdC;');
define('LOGGED_IN_KEY',   '9:z95.y<_LhUnGlH>6%)/-szx8Dwj{z`#mz-C%taXoD:KK86k(?K-f{w]U5w(41v');
define('NONCE_KEY',       '?YP2djRHOn7[4n[p(KwmX#u.#^s3Fel%AKu@Ac,(L$1DM^@6NNk@x&B/w2/<an:@');
define('AUTH_SALT',       '$r>m{8@l?xDv<^uNz^.|<Am2}J3q(OMAS<dLB({66M)zy2ufOP8$x*{:US|7PL4x');
define('SECURE_AUTH_SALT','Nn4uU#rIe}7CaXw=Z?pk82Cqo8{ALC6McPHYq_G{><]_YWhHlEuk?`tJ6G[)D$)A');
define('LOGGED_IN_SALT',  'YLiGuP$DPKP-F3UGw(0#E0L1w;HO0L_Hkt6.(*92t*B6Mclq*`{OO[xM$3)]^9yi');
define('NONCE_SALT',      '{hh3bpLu$b:e8-uXiCx(3FaK3Q4[`/Mji}~<.cz8W#_a0[O!{h;Fm{^c]p>./RF{');