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Re: Using a password as a private key.



Why not encrypt the private key with a 128 bit symmetric key (created from the hash of a username and paasword)
and store on a keyserver, along with the public key?
That way, you don't have to store it yourself locally, you get it off the keyserver.
I wrote a keyserver that does just that.  In addition, it also verifies ies the user before returning the key.
It requires the user to encrypt a known string with a separate password.
The encrypted string is sent to the keyserver, encrypted with the keyserver's public key.
Seems rather safe. Anyone disagree?

-Chris

P.S. I might not use it for military purposes, but for company email...

"RedRook" <[email protected]> wrote:
>Date: Tue, 27 Oct 1998 13:53:07 -0800 (PST)
>&#130;&#130;&#130;&#130;Assymetic crypto systems such as
>Diffie-Hellman, El-Gamel, and DSS, allow the private key to be a
>randomly chosen number. &#130;But, as a cute hack, instead of using a
>random number, for the private key, you could use a hash of the User
>Name, and a password. 
>
>Doing so allows the users to generate their private key on demand.
>They don't have to store the private key, and if they want to work on
>a another computer, they don't need to bring along a copy.&#130;
>Has any one tried this? Is there existing software that does this? Any
>comments on the security of such a scheme? &#130;
>The only draw back that I can think of is the potential lack of
>randomness in the key. If the user chooses a bad password, it would be
>possible to brute force the public key.&#130;
>Harv.&#130;&#130;[email protected]&#130;&#130;&#130;&#130;&#130;&#130;&#130;&#130;
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