@ Nonnull public DigestAuthServerBuilder setOpaque ( @ Nonnull final String sOpaque ) { if ( ! HttpStringHelper . isQuotedTextContent ( sOpaque ) ) throw new IllegalArgumentException ( "opaque is invalid: " + sOpaque ) ; m_sOpaque = sOpaque ; return this ; }
A string of data specified by the server which should be returned by the client unchanged in the Authorization header of subsequent requests with URIs in the same protection space . It is recommended that this string be base64 or hexadecimal data .