This doesn't necessarily solve your problem, but new versions of Firefox, Chrome, Opera, and IE all provide CSPRNGs. It's experimental, but it's been available

This doesn't necessarily solve your problem, but new versions of Firefox, Chrome, Opera, and IE all provide CSPRNGs. It's experimental, but it's been available in Firefox for several versions. So if you have a modern browser, just open your console window, and try: window.crypto.getRandomValues(typedArray) On mobile, this random number generator is unfortunately not available on Android's browser, although it is available on Chrome for Android, Firefox Mobile, and Safari on iOS and up. There's also a full browser-based Crypography API in the works. You can see the draft here: http://www.w3.org/TR/WebCryptoAPI/ http://www.w3.org/TR/WebCryptoAPI/ Once all of this is implemented, the chicken and egg problem is solved, since the browser will then have native crypto primitives available. At that point, the main argument I see against browser-based crypto in JavaScript is the malleability of the Javascript runtime. And if you believe that's an intractable problem, then you should probably reconsider the use of any language for crypto that can be monkey-patched, including common server-side languages like Python, Ruby, and to a certain extent PHP.