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Re: Cypherpunk Certification Authority

2 expanded posts ยท every known parent and child

NODE a6444b1dRe: Cypherpunk Certification Authority
On Sat, 25 Nov 1995, Adam Shostack wrote:

> 	Does X.509 version 3 fix the problem that Ross Anderson points
> out in his 'Robustness Principles' paper? (Crypto '95 proceedings, or
> ftp.cl.cam.ac.uk/users/rja14/robustness.ps.Z)
> 
> 	Its an excellent paper, well worth reading, but the basic
> problem is that X.509 encrypts before signing.

You'd rather sign before encryption??

Doesn't that give you "known plain-text" to attack?  i.e. the signature.

I'm not sure whether it would or wouldn't, but I'm sure some
cryptographers here might clear that up mighty quick -- before any more
harm is allowed, I mean. 

> Adam
> 
> -- 
> "It is seldom that liberty of any kind is lost all at once."
> 					               -Hume


Alice de 'nonymous ...

                                  ...just another one of those...


P.S.  This post is in the public domain.
                  C.  S.  U.  M.  O.  C.  L.  U.  N.  E.
NODE 75fbd254Re: Cypherpunk Certification Authority
Hello,

On Sun, 26 Nov 1995 anonymous-remailer@shell.portal.com wrote:

> > 	Its an excellent paper, well worth reading, but the basic
> > problem is that X.509 encrypts before signing.
> 
> You'd rather sign before encryption??
> 
> Doesn't that give you "known plain-text" to attack?  i.e. the signature.
> 
> I'm not sure whether it would or wouldn't, but I'm sure some
> cryptographers here might clear that up mighty quick -- before any more
> harm is allowed, I mean. 

  The paper suggested that you have two different keys, one for 
encryption and the other for signatures, and you don't mix the two up, so 
that way you are protecting yourself from someone forging your 
signature, but you are not letting them know what your private key is.
  Make sense?  I would suggest that you read the paper, as it is really 
an excellent document.

==========================================================================
James Black (Comp Sci/Comp Eng sophomore)
e-mail: black@eng.usf.edu
http://www.eng.usf.edu/~black/index.html
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