Is Math.random() cryptographically secure?

Question

How good are algorithms used in Javascript Math.random() in different browsers? Is it okay to use it for generating salts and one-time passwords?

How ma

Answer 1

It is not secure at all, and in some cases was so predictable you could rebuild internal state of the PRNG, deduct the seed and thus could use it to track people across websites even if they didn't use cookies, hid behind onion routing etc...

• http://landing2.trusteer.com/sites/default/files/Temporary_User_Tracking_in_Major_Browsers.pdf a 2008 paper exposing the user tracking possibilities of the browser weak PRNG

• http://dl.packetstormsecurity.net/papers/general/Google_Chrome_3.0_Beta_Math.random_vulnerability.pdf a later (2009) Chrome vulnerability, as the problem was already well known