Email Portability, DKIM, and Socio-Political Implications on Tech Development

By Gadi Evron
Gadi Evron

A few years ago, cell phone portability was introduced in the United States which caused a major shift in the market. The same thing happened this past year in Israel, following a major battle involving the cell carriers, consumer groups and the Israeli parliament (The Knesset).

What if the same happened with email addresses? Ridiculous, you say?

May be so, but there is chatter here in Israel to create a law which forces the local service providers hands to do just that.

This is a fascinating concept, and the technological solutions range from plain (forwarding, shared email hosting, list of "exceptions" to be handled at the Domain Name System (DNS) or Mail transfer agent (MTA) levels) to unbelievable (shared MX records, central email root).

Email portability is a fascinating concept, and one which will eventually happen. Technologically it makes little sense, but it is the consumer which decides where technology goes. Tech solutions aside, the question which comes to mind is, doesn't this completely break DomainKeys Identified Mail (DKIM)?

I am far from a DKIM expert, so I would just hazard a guess: yes.

Us techies often find it challenging to look into the future, considering political and sociological implications. However, there are some which we may want to consider, developing future technology.

By Gadi Evron, Security Strategist. Visit the blog maintained by Gadi Evron here.

Related topics: Email, Law, Policy & Regulation


Provided that the body and signed header Jim Fenton  –  Aug 07, 2008 12:45 PM PST

Provided that the body and signed header fields are not altered in the forwarding process, DKIM signatures should be expected to survive.  This specific use case was considered in the design of DKIM and is an advantage of signature-based authentication.

Jim, thank you for clarifying that point. Gadi Evron  –  Aug 07, 2008 3:08 PM PST

Jim, thank you for clarifying that point. I appreciate your correction.

It also seems to me, though, that forwarding may not be the technology of choice for these ISPs.

What are the other technologies of choice? Jim Fenton  –  Aug 08, 2008 12:17 AM PST

I don't really understand the alternatives you mention: Handling exceptions at the MTA is very much like forwarding, and some sort of MX record hack seems even less likely to modify the message in a way that would break the signature.  Am I missing something?

Yes, the legislator may demand a movement, Gadi Evron  –  Aug 08, 2008 2:40 AM PST

Yes, the legislator may demand a movement, not of the pointer but of the object, the mailbox.

Get your own domain name and you Katya Nováková  –  Aug 12, 2008 2:51 PM PST

Get your own domain name and you have mail portability.