[Haskell-cafe] [Haskell] ANN: nonce package

[Tobias Dammers]

Looks useful; feature request: something like

    nonce :: MonadIO => Int -> Generator

(plus -url and -T flavors, obviously). I believe allowing the programmer
to balance security vs. usability demands would be a good thing overall
and worth a knob.

-> m ByteString
On Fri, May 22, 2015 at 08:06:18PM -0300, Felipe Lessa wrote:
> (Please forgive me if you received multiple copies of this e-mail.)
> 
> Hello,
> 
> The nonce package [1] contains functions to easily generate
> cryptographic nonces for many situations.  Some places where these
> generated nonces can be used include:
> 
>   - Password recovery e-mail tokens.
> 
>   - XSRF protection tokens.
> 
>   - Session IDs sent on cookies.
> 
>   - Initialization vectors.
> 
> It uses an AES CPRNG periodically reseeded from /dev/urandom (or
> equivalent).  It has no frills, no knobs, so it's hard to misuse.  It's
> been available for an year but I just realized I've never properly
> announced it.
> 
> Regrettably, I've seen many uses of the random package (System.Random)
> when generating nonces.  It's a bad choice: it is not a
> cryptographically secure PRNG, contains low entropy (64-bit state), and
> its default usage is seeded predictably (using a constant seed).  Please
> avoid using the random package for generating nonces at all costs.  In
> its stead, use the nonce package or something similar.
> 
> Cheers,
> 
> [1] http://hackage.haskell.org/package/nonce
> 
> -- 
> Felipe.
> 



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-- 
Tobias Dammers - tdammers at gmail.com