[whatwg] Cryptographically strong random numbers

Adam Barth w3c at adambarth.com
Sat Feb 5 02:10:17 PST 2011

On Fri, Feb 4, 2011 at 9:00 PM, Cedric Vivier <cedricv at neonux.com> wrote:
> On Sat, Feb 5, 2011 at 08:42, Adam Barth <w3c at adambarth.com> wrote:
>> interface Crypto {
>>  Float32Array getRandomFloat32Array(in long length);
>>  Uint8Array getRandomUint8Array(in long length);
>> };
> I think the API would be more flexible and more future-proof defined as :
> interface Crypto {
>    void getRandomValues(in ArrayBufferView data);
> }
> getRandomValues(in ArrayBufferView data)
> Fills a typed array with a cryptographically strong sequence of random values.
> The length of the array determines how many cryptographically strong
> random values are produced.
> We had same discussion when defining readPixels API in WebGL.
> Advantages :
> 1) this allows to reuse the same array over and over when necessary,
> or circular buffer, instead of trashing the GC with new allocations
> everytime one wants new random bytes.
> 2) this allows to fill any integer array directly (Float*Array might
> need more specification here though as Boris pointed out - could be
> disallowed initially)
> 3) this avoids exposing N methods for every type and makes refactoring
> simpler (changing the array type does not require changing the
> function call)
> (and also better matches most existing crypto APIs in other languages
> that are also given an array to fill rather than returning an array)

Oh, that's very cool.  Thanks.


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