## The 3 layers of a license

Creative Commons licenses are built using a three-layer design.

1. Legal code: “Lawyer-readable” terms and conditions that are legally enforceable in court.
   Example: the legal code of CC BY

2. Commons deed: The license explained in “human-readable” terms. These deeds are not legally enforceable; they only summarize the legal code. In a deed you can find the link to the legal code.
   Example: the deed for CC BY

3. CC Rights expression language (CC REL): A “machine readable” version of the license including the key freedoms granted and obligations imposed of a license. CC REL is formatted to be readable by applications, search engines and other kinds of technology. You can read more about CC REL in the CC wiki.

In this chapter you've learned what CC licenses are, what the different licenses are and what they permit.
The next segment will tell you how to find these materials.