And more generally, this is what NeXT's developer documentation has to say about services... Good stuff. -Declan ---- Examples of a Few Possible Services Here are a few examples of services that have already been implemented to give you an idea of what can be done with NeXTSTEP's services mechanism: * Encryption An encryption service can convert data to a more secure form. For example, Mail can place a mail message on the pasteboard as a standard Rich Text Format (RTF) document, and another application could encrypt the document and place it back into mail as unreadable ASCII text, or as a document to be opened only by another external decryption application. Excerpts from internet.cypherpunks: 20-Jun-96 Re: Safemail by Andrew Loewenstern@il.us
One interesting thing about NeXT's software is that the Mail application has
crypto hooks. The crypto code is in a drop-in bundle that extends the app at runtime. This isn't just a generic interface, but the internationally shipped Mail software calls methods in the external bundle that are definitely crypto related. Also, much of the crypto and key management user
interface ships with the main Mail package. It is hidden without the crypto
bundle, but if you peek around with InterfaceBuilder you can see that it is there.