ietf-openpgp
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Re: Split Implementations of PGP

2005-03-11 18:15:15

On 3/11/05, eburger(_at_)brooktrout(_dot_)com (Eric Burger) wrote:


Background:
I am a co-chair of the lemonade work group in the IETF
<http://www.ietf.org/html.charters/lemonade-charter.html>.

One thing we would like to do is enable a remote client to fetch the
encrypted session key from an IMAP server, decrypt the key using the
client's key, and then handing back the clear session key to the IMAP server
to decrypt or verify a message or body part.

I understand, from Derek's draft minutes of the OpenPGP meeting, that the 
problem is that the remote client is in a low-bandwidth environment, such as a 
cell phone.  I understand this statement to mean that the communication link is 
low bandwidth.  However, PGP encrypted messages are close to the size of the 
corrisponding plain text, so I don't see how having an IMAP server decrypt the 
message is going to help.

If, on another hand, the remote client is limited in CPU power, this system 
seems to place the largest CPU load, the public key operation to extract the 
plain text key, on the client, and the relatively low CPU load of the private 
key operations to decrypt the message on the IMAP server.

I conclude from this reasoning that I don't understand the problem.  Could you 
please explain.

Thanks - Bill

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