Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: [PATCH 6/12] random pt4: Replace SHA with faster version | Date | Tue, 25 Jan 2005 23:31:19 +0200 |
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On Tuesday 25 January 2005 23:14, Matt Mackall wrote: > On Tue, Jan 25, 2005 at 11:07:21PM +0200, Denis Vlasenko wrote: > > On Friday 21 January 2005 23:41, Matt Mackall wrote: > > > - * @W: 80 words of workspace > > > + * @W: 80 words of workspace, caller should clear > > > > Why? > > Are you asking why should the caller clear or why should it be cleared at all? > > For the first question, having the caller do the clear avoids > redundant clears on repeated calls. > > For the second question, forward security. If an attacker breaks into > the box shortly after a secret is generated, he may be able to recover > the secret from such state.
Whoops. I understood a comment as 'caller should clear prior to use' and this seems to be untrue (code overwrites entire W[80] vector without using prior contents).
Now I think that you most probably meant 'caller should clear AFTER use'. If so, comment should be amended. -- vda
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