It is designed to reject backscatter, that is, bounce messages to forged return addresses.
The basic idea is to send all e-mail with a return address that includes a timestamp and a cryptographic token that cannot be forged.
BATV replaces an envelope sender like mailbox@example.com with prvs=tag-value=mailbox@example.com, where prvs, called "Simple Private Signature", is just one of the possible tagging schemes; actually, the only one fully specified in the draft.
Other types of implementations, such as using public key signatures that can be verified by third parties, are mentioned but left undefined.
In late 2004, Goodman et al. proposed a much more complex "Signed Envelope Sender"[2] that included a hash of the message body and was intended to address a wide variety of forgery threats, including bounces from forged mail.