ASN.1 type ContentType is defined as follows:

    ContentType ::= CONTENTS.&id({Contents})

    CONTENTS ::= TYPE-IDENTIFIER  -- Defined in ISO/IEC 8824-2, Annex A

    Contents CONTENTS ::= {
       { SignedData             IDENTIFIED BY  id-signedData            } |
       { EnvelopedData          IDENTIFIED BY  id-envelopedData         } |
       { AuthenticatedData      IDENTIFIED BY  id-ct-authData           } |
       { DigestedData           IDENTIFIED BY  id-digestedData          } |
       { EncryptedData          IDENTIFIED BY  id-encryptedData         } |
       { NamedKeyEncryptedData  IDENTIFIED BY  id-namedkeyencryptedData } |
       { Data                   IDENTIFIED BY  id-data                  },

       ...  -- Expect additional content type objects --
    }