ASN.1 parameterized type Attribute {} contains two components named attrType and atrValues. The valid values of these two components are constrained by the contents of its single paramenter, an information object set of information class ATTRIBUTE named IOSet.

    Attribute { ATTRIBUTE:IOSet } ::= SEQUENCE {
       attrType    ATTRIBUTE.&id({IOSet}),
       atrrValues  Values {{IOSet}}
    }

    Values  { ATTRIBUTE:IOSet } ::= SET OF ATTRIBUTE.&Type({IOSet})

    ATTRIBUTE ::= CLASS {
      &Type  OPTIONAL,
      &id    OBJECT IDENTIFIER  UNIQUE
    }
      WITH SYNTAX { [WITH SYNTAX &Type] ID &id }

See AuthAttributes for an illustrative example of how this parameterized type is applied in CMS messages.