[brownbat]

Moreover, if the server stores enough information for a recipient to read the message, then the server effectively stores the message.

[brownbat]

Hmm, oh, I think the stuff after the hash is the decryption key, and we're assuming the server throws it away.

We still require a trusted third party here.

[StavrosK]

The HTML anchor never reaches the server in the request, it's for local use only. Of course, malicious JS on the page can always send it anywhere.