BIP 0038

  BIP: 38
  Layer: Applications
  Title: Passphrase-protected private key
  Author: Mike Caldwell <mcaldwell@swipeclock.com>
          Aaron Voisine <voisine@gmail.com>
  Comments-Summary: Unanimously Discourage for implementation
  Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0038
  Status: Draft (Some confusion applies: The announcements for this never made it to the list, so it hasn't had public discussion)
  Type: Standards Track
  Created: 2012-11-20
  License: PD

The full text of this BIP can be read here.