RE: key storage

["Roman Fail" <rfail () posportal com>]

Wouldn't it be a better practice to have all the encryption/decryption occur on the proxy machine itself?  Since he 
does not have control over the webserver he does not know how well hardened it is.  He can harden the proxy himself and 
the key never leaves the proxy machine.  If the webserver is compromised, at worst the attacker can encrypt/decrypt 
until discovered but never determines the key.  Of course this is largely predicated on a decent connection speed 
between the two servers since the actual data must be transmitted (securely) rather than just the key.  
 
On another note, how should the webserver authenticate itself to the proxy (especially if unattended)?  I have Googled 
extensively for best practices in this scenario and come up with lots of vendor fluff but little hard information.
 
Roman Fail
 

        -----Original Message----- 
        From: Brown, James F. [mailto:James.F.Brown () FMR com] 
        Sent: Mon 8/30/2004 7:00 AM 
        To: Ajay 
        Cc: webappsec () securityfocus com 
        Subject: RE: key storage
        
        

        No problem. That's the "best practice", I believe.
        
        - Jim
        
        -----Original Message-----
        From: Ajay [mailto:abra9823 () mail usyd edu au]
        Sent: Monday, August 30, 2004 9:29 AM
        To: Brown, James F.
        Cc: webappsec () securityfocus com
        Subject: RE: key storage
        
        
        yup, thats the idea. do you see any problems with it
        
        cheers
        
        
        Quoting "Brown, James F." <James.F.Brown () FMR com>:
        
        > You're going to use the SHA-1 hash of the passphrase as the actual key
        > for the symmetric encryption, right?
        >
        > ================================
        > James F. Brown  CISM, CISA
        > Sr. Director, Information Security
        > Fidelity Investments
        > james.f.brown () fmr com
        > http://www.fidelity.com
        >
        >
        > -----Original Message-----
        > From: Ajay [mailto:abra9823 () mail usyd edu au]
        > Sent: Saturday, August 28, 2004 12:25 AM
        > To: Brown, James F.
        > Cc: George Capehart; webappsec () securityfocus com
        > Subject: RE: key storage
        >
        >
        > thanks.
        > from responses on other mailing lists, i am moving towards the idea of
        > having some sort of proxy server application which at startup is
        > supplied
        > a passphrase. it uses the passphrase to decrypt a passphrase encrypted
        > file and loads keys from there. the file itself can be removed then
        > my main application can then query the proxy when it needs the keys.
        > ofcourse this introduces the problem of securing the exchange between
        > the
        > main and the proxy.
        > the reason i have the proxy in the first place is because my main app
        is
        > a
        > bunch of cgi scripts where state is stored by only writing to a file
        and
        > i
        > do not have access to the webserver where the application is hosted.
        > it will all be remarkable slow though...
        >
        > cheers
        >
        > --
        > Ajay Brar,
        >
        > Quoting "Brown, James F." <James.F.Brown () FMR com>:
        >
        > > Chapter 8 in Applied Cryptography only discussed key storage in
        areas
        > > where users are involved. If you have an server application that
        uses
        > > crypto with no users involved, it doesn't offer much help. I'll
        check
        > > Bruce's newer book "Practical Cryptography" to see if he's addressed
        > > that topic, but I won't be able to report on it until Monday.
        > >
        > > ================================
        > > James F. Brown  CISM, CISA
        > > Sr. Director, Information Security
        > > Fidelity Investments
        > > james.f.brown () fmr com
        > > http://www.fidelity.com
        > >
        > >
        > > -----Original Message-----
        > > From: George Capehart [mailto:gwc () acm org]
        > > Sent: Thursday, August 26, 2004 1:41 PM
        > > To: webappsec () securityfocus com
        > > Subject: Re: key storage
        > >
        > >
        > > On Wednesday 25 August 2004 21:12, Ajay allegedly wrote:
        > > > and also is there any significant paper on key storage - a journal
        > or
        > > > conference paper?
        > > > its for my thesis and it would be nice if i could quote a the
        > > > findings of some paper
        > >
        > > Ajay,
        > >
        > > There has been *lots* written about key storage.  It's a pretty
        > > important topic . . . :>  Google is your friend.  A great place to
        > > start, though is Chapter 8 (Key Management) in _Applied_Cryptology
        > > (ISBN 0-471-11709-9) by Bruce Schneier.
        > >
        > > Cheers,
        > >
        > > George Capehart
        > > --
        > > George W. Capehart
        > >
        > > Key fingerprint:  3145 104D 9579 26DA DBC7  CDD0 9AE1 8C9C DD70 34EA
        > >
        > > "With sufficient thrust, pigs fly just fine."  -- RFC 1925