BETA solution, Re: Failure of PKI in messaging

[Ed Gerck]

Guus Sliepen wrote:
> On Thu, Feb 15, 2007 at 02:47:05PM -0800, Ed Gerck wrote:
> 
>> Zmail actually reduces the amount of trust by not storing your usercode,
>> password, or keys anywhere. This makes sense for zmail, and is an incentive
>> to actually do it, to reduce risk -- anyone breaking into any zmail server,
>> even physically, will not find any key or credential material for any user
>> and, hence, cannot decrypt any user area (the user area keeps the address book
>> and contact keys, all encrypted using the user keys that are not there), or
>> user messages collected from ISPs.
> 
> Where are the usercode, password and keys stored then?

N O W H E R E, as it says above.

> [...]
>> This will actually be available in v3.x, with an option for client-based
>> super-encryption. If you are concerned about zmail peeking into the raw
>> message, which zmail does not do, you can simply agree with your message
>> partner on an out-of-band passphrase and use it in your client (without
>> zmail access) to encrypt. Your recipient can do the same to decrypt. What
>> you get from zmail is the secure routing and distribution -- for example,
>> you can require the recipient to login, allow the recipient to prevent
>> phishing, and expire the message in 7 days. You can also request a return
>> receipt telling you when, where, how, and by whom the message was decrypted.
> 
> /If/ I trust ZMail (the people behind it and the X.509 stuff that
> secures the website) then yes, this is functionality not offered by SMTP
> and PGP or S/MIME. But I don't see this replacing PGP or S/MIME. 

There's no need to replace PGP or S/MIME. After all, less than 5% of all email
is encrypted using them. What's needed is to offer an option for the other
95% that could be encrypted and authenticated.

>I also
> still don't see how this improves the trust model.

Because you have to trust zmail less (the two quotes above), and also because
you have to trust the recipient less (the return receipt, for example). In
addition, you have to trust your platform less (no private-key that is stored
in your computer; ZSentryID can be used to render key-logging ineffective).
In short, the less you have trust everyone (including your own computer),
the better the trust model is -- what you trust is what can break your
security, when it fails.

Best,
Ed Gerck

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