An attribute option is a kind of tag that provides additional information about the way that an attribute should be interpreted. An attribute description consists of the attribute name or OID followed by zero or more attribute options. If there are attribute options, then they are separated from the attribute name and from each other using semicolons. For example, in the attribute description userCertificate;binary, the attribute name is userCertificate and the attribute option is binary.
Attribute options can be used for several purposes, including providing information about how the server should treat that attribute (for example, the binary encoding option as described in RFC 4522) They may also be provided for the benefit of clients in some form (for example, the language tag options as described in RFC 3866, which make it possible to provide an attribute value in different languages).