An idea for gmail

How about revoking emails? Namely, the user sending something to @gmail.com could also send a special "mail revoke" message to revoke his sent mail. If the sender is also a gmail user, he could be offered a simple GUI option. To eliminate potential privacy concerns, the feedback would be either "revoke received" or "trying to revoke invalid message". Any other kind of message would let the sender know whether his mail was already read or not.

What would be the safe contents of such message? Something like SHA1(sender_address || SHA1(mail_body)) would be sufficient, although crude in the first iteration.

More importantly, mechanisms to securely "revoke" only own messages are available, why isn't such option already implemented?



Anonymous said...

Implementing such a thing is in fact quite controversial. The main problem is that you cannot allow revoking of seen messages. Mails are often used as evidence of commitment, especially among business partners and between employees and their superiors. "Saving all your mails so you can back up your word" has become a recognized tenet in many environments. If you allow revocation of emails, then anyone can back down on their word simply by revoking the mail and therefore effectively destroying the evidence.

On the other hand, if you allow revocation only of unread mails, then the feature is much less useful for genuine mistakes.

The gmail people probably correctly concluded that the email system is not yet ready for such a feature and decided to refrain from trying to implement it.

zvrba said...

I was thinking of revoking only unread messages.

Even revoking read messages wouldn't be a great problem since the user can always make a backup not accessible to the mail server software (although, it'd be a nuisance). And revoking read messages is, IMHO, useless.. what the recipient reads, cannot be "unread".

Anonymous said...

Verba volant, scripta manent.

(Our cultural fundamentals include a small number of paradigms that even I wouldn'l like to se subverted :)