to fix all of these issues at the same time. At one end of the system, AOCE focuses on the underlying delivery and addressing systems, generalizing the email concept so the system can be used to deliver anything from email to word processor documents to print jobs. Addressing was another issue the market was struggling with, so AOCE offers a single universal addressing mechanism and address book, one that could support not only people's email addresses, but the addresses of things like printers and fax machines as well. These could be looked up in an interface much easier to use than the existing Macintosh solution, the Chooser. AOCE normally store users' email on each personal computer, as opposed to a server. This not only allows the user to read mail offline, but also removes the need for a single machine with huge storage space. Small networks can be set up simply by installing the standard client software; the machines discover each other on AppleTalk and communicate directly. AOCE understands that users are not always connected to the network, so outbound mail is cached on the sender's machine until both the sender and recipient are online. Even on a LAN this is valuable, as many users turn off their computers at night and the mail would must wait until the next morning for delivery. Since the mail is stored locally, users with laptop computers are able to read and compose mail while mobile. Everything automatically updates upon reconnection to the office LAN. AppleTalk Remote Access, Apple's standard implementation of AppleTalk over modems, provides remote sync. For security over the potentially open phone lines, all communications can be secured using RSA encryption and digital signing, even on the local network. Additionally, the Keychain stores various login credentials in an encrypted file. This allows the users to use a different username and password on the various systems, placing them in the keychain database for secure storage. This requires only a single password for the keychain; AOCE can retrieve the credentials for a particular service on demand. Users can share documents directly simply by dropping the address on the document, or vice versa, bypassing a message at all – the document would arrive automatically in the other user's mailbox. Delivery of email (which in this scenario is nothing more than a text document in a specialized format), or of anything else, was handled entirely