[cryptography] Duplicate primes in lots of RSA moduli

Ben Laurie ben at links.org
Sat Feb 18 13:04:24 EST 2012


On Fri, Feb 17, 2012 at 8:39 PM, Thierry Moreau
<thierry.moreau at connotech.com> wrote:
> Ben Laurie wrote:
>>
>> On Fri, Feb 17, 2012 at 7:32 PM, Thierry Moreau
>> <thierry.moreau at connotech.com> wrote:
>>>
>>> Isn't /dev/urandom BY DEFINITION of limited true entropy?
>>
>>
>> $ ls -l /dev/urandom
>> lrwxr-xr-x  1 root  wheel  6 Nov 20 18:49 /dev/urandom -> random
>>
>
> The above is the specific instance on your environment. Mine is different:
> different kernel major/minor device numbers for /dev/urandom and
> /dev/random.

So? Your claim was "Isn't /dev/urandom BY DEFINITION of limited true
entropy?" My response is: "no".

> I got the definition from
>
> man 4 random
>
> If your /dev/urandom never blocks the requesting task irrespective of the
> random bytes usage, then maybe your /dev/random is not as secure as it might
> be (unless you have an high speed entropy source, but what is "high speed"
> in this context?)

Oh, please. Once you have 256 bits of good entropy, that's all you need.



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