Re: Public exponenet e in Private Key Blob

From: Valery Pryamikov (valery_at_harper.no)
Date: 11/23/05


Date: Wed, 23 Nov 2005 22:05:26 +0100

Windows uses standard public exponent 2^16+1. that gives good performance
due to low humming weight (only two 1 bits and 14 x 0 bits) and good
cipher's security due to guarantee against number of attack (such as f.e.
cuperthmith's attack) and only few messages that are encrypted to
themselves, with using randomized padding (which must be used with RSA
encryption) your chances to get such message is lower than chances of all
particles of our universe suddenly seizes to exist.
3 would be even a better public exponent if used with OAEP or (even better)
RSA-KEM.

-Valery.
http://www.harper.no/valery

"Shankar" <Shankar Agarwal@community.nospam> wrote in message
news:36D3F0C2-D504-4A9B-BF2E-EE2373ED7969@microsoft.com...
> Hi,
> In the Private key blob I am presuming that the public exponenet is stored
> in rsapubkey.pubexp. Is this right?
> But then it is fixed to 32 bits. This made me suspicious if I am doing
> something wrong.
> Is this universal or just that Windows support 32 bit public exponenet
> only.
> Thanks a lot for your help.
> Shankar



Relevant Pages

  • Re: RSA signing security
    ... open to an attack using smoothness. ... discussed in "On the security of RSA padding" ... on if the adversary can obtain the signature of messages ... few exceptions where a low public exponent, e.g. e=3, ...
    (sci.crypt)
  • Re: http://www.openssl.org/news/secadv_20060905.txt
    ... upcoming OpenSSL issues via vendor-sec -- but on first glance it looks like ... it looks like the attack isn't limited to keys with a public exponent ...
    (FreeBSD-Security)
  • Re: Generating RSA key with different public exponent
    ... 3 is a tricky public exponent. ... having a bug allowing the attack. ... to stop using RSA keys with exponents of 3. ... Kris Sheglova ...
    (microsoft.public.dotnet.security)