Secure XML: The New Syntax for Signatures and Encryption

5.2. Types

A fundamental concept of schema is that of a type. In this section, we discuss named types. You can also use anonymous types, as detailed in Section 5.3.

5.2.1. simpleType

A simpleType is a named type that cannot contain element content and cannot carry attributes. All attributes have a simpleType. Elements that are empty or have only text content are also simpleTypes. The Schema Recommendation provides a large number of predefined simpleTypes, the most general of which is “string.” Most of these types have fairly descriptive names, such as “integer,” “dateTime,” and “anyURI.” XML Security uses the “base64Binary” simpleType extensively; it indicates an octet stream encoded in base-64 [RFC 2045]. All of the special attribute types declarable ...