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<TITLE>RE: PuTTY compatibility: Does gen_rsa_priv_key still need to regenerate primes until modulus is a multiple-of-8-bits long ?</TITLE>
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<P><FONT SIZE=2>Matt,<BR>
Thanks, that was really quick!<BR>
<BR>
Regards,<BR>
-- Sajin<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: Matt Johnston [<A HREF="mailto:matt@ucc.asn.au">mailto:matt@ucc.asn.au</A>]<BR>
Sent: Fri 9/12/2008 12:49 PM<BR>
To: Valoth, Sajin [NETPWR/EMBED/MA]<BR>
Cc: dropbear@ucc.asn.au<BR>
Subject: Re: PuTTY compatibility: Does gen_rsa_priv_key still need to regenerate primes until modulus is a multiple-of-8-bits long ?<BR>
<BR>
On Fri, Sep 12, 2008 at 10:32:01AM -0500, Sajin.Valoth@Emerson.com wrote:<BR>
> Hi all,<BR>
> <BR>
> With dropbear 0.48.1 running on a MIPS Au1550 platform,<BR>
> RSA key generation occasionally takes a very long time (multiple<BR>
> minutes);<BR>
> the problem was traced to the loop shown below in<BR>
> gen_rsa_priv_key()<BR>
> which executes many times, until a value of the modulus, n,<BR>
> is finally computed that is a multiple-of-8-bits long.<BR>
...<BR>
> <BR>
> However, using more recent versions of PuTTY (0.58 and 0.60),<BR>
> I don't see any problems<BR>
> with keys generated by dropbear where the modulus is not a<BR>
> multiple-of-8-bits long.<BR>
> <BR>
> So, my question is: should the loop above be deprecated since<BR>
> it doesn't appear to be necessary any more?<BR>
<BR>
Yes, it looks like this was fixed in PuTTY 0.54 in 2004 [1],<BR>
so can be removed. Thanks for letting me know.<BR>
<BR>
Cheers,<BR>
Matt<BR>
<BR>
[1] <A HREF="http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/rsa-non8mult-verify-fail.html">http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/rsa-non8mult-verify-fail.html</A><BR>
<BR>
<BR>
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