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Re: Introducing TGP...
From: Brandon Enright <bmenrigh () ucsd edu>
Date: Wed, 16 Jun 2010 23:00:32 +0000

Hash: SHA1

On Wed, 16 Jun 2010 22:23:04 +0000
"Thor (Hammer of God)" <Thor () hammerofgod com> wrote:

You're using a 1024 bit key here which seems a bit gutsy ;-)

Without better attacks, you basically have:

Brute force AES 256 -> O(2^256)
Bruce force your 20 char password -> roughly O(2^(20*7)) ==
O(2^140) Factor your 1024 bit public modulus -> roughly O(2^80)

Since a 768 bit RSA key has already been factored I'd say you only
have a few years before a moderately sized cluster could factor
your public key.

Of course, as I write this I realize I'm about to sign this message
with a 1024 bit DSA key...

Actually it's 2048, which I was comfortable with.  And don't forget
the 16bit salt on that password ;)


- From your message:


Which decodes to:


So your encrypting exponent is 65537, pretty standard choice.

And your modulus is:


Which is a 1024 bit number -- roughly 1.53 * 10^308 or 2^1023.7671

Also, the cipher text of your encrypted AES key is 1024 bits --
consistent with being encrypted with 1024 bit RSA.

Finally, your example KeyNaCl:


Is 16 bytes, not 16 bits.

A reasonable assumption is that the attackers already have your private
key fob and so they have the salt.  That is, a salt doesn't add to a
brute force complexity when you are attacking just a single password.


Version: GnuPG v2.0.15 (GNU/Linux)

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