Re: [GNU Crypto] Small problem with HMac

[Raif S. Naffah]

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hello Casey,

On Thursday 09 January 2003 23:22, Casey Marshall wrote:
> Hi,
>
> It looks like there is a small problem with how HMac is reset...
>
> The attached seems to fix this...
>
> @@ -180,18 +184,31 @@
>        underlyingHash.reset();
>        opadHash = (IMessageDigest) underlyingHash.clone();
>  
> +      ipad = new byte[blockSize];
> +

this allocates new byte array _every_ time an hmac is init-ed.  we only 
need doing that for new keys, and only if the key length is different 
from the previously used initialisation (if there was one).  once ipad 
is present, there's no need to worry about it being set to zero-bytes, 
since it will get populated with K ^ IPAD.


a test case of a re-use would be nice to have ;-)


cheers;
rsn
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