At 15:51 02-03-10, Takaaki Higuchi wrote: >Fist of all, I don't think IDN has interoperability problems with DKIM. >IDN is designed not to affect any impact to existing DNS system. >(So punycode encoding, which encodes unicode to ascii, is used)
If you consider that only A-labels are used for the "d=" tag, it does not affect the retrieval of the (DKIM) public key. Selectors can be constrained similar to what is being done for service labels. >At first, I thought EAI is only extend IDN punycode to local part of E-mail >address. But it is wrong. EAI extends SMTP to express full E-mail address >as internationalized. Yes. >My rough understanding is that EAI is put e-mail address into From: with >both unicode encoded and current style. When recipient SMTP server Yes. >does not support EAI, it downgrades to connect to the recipient. >Which means delete unicode part from From: hearder. That makes DKIM >verification breaks. There may be changes to Downgrade. Both the experimental specification or its revision will cause DKIM verification failures when the message is downgraded. DKIM signing and verification of UTF-8 headers will require a change in some implementations. There will be more room for visual spoofing. There is also the question of whether to use U-labels. Regards, -sm _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
