| Seems to me you're making the assumption that I don't know about SPF or domainkeys, et al. They fail because they try to stop spam within the MTA and don't give enough control the recipient to determine the level of trust they're willing to accept. All that remains is the way you determine trust; X.509 certificates or various signature schemes.
The MTA is built around trust, but that doesn't mean the client has to impart the same trust. Using multipart MIME formatting makes it compatible with existing mail systems, and isn't any more of a kludge than HTML/rich text formatting. |
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