An apparatus is described. The apparatus comprises: communication circuitry configured to receive from a submitter, over a network, a data item of a first data type, wherein the data item comprises a plurality of components and the apparatus further comprises: processing circuitry configured to: sequentially receive the plurality of components of the data item and for each component in succession in the sequence, the processing circuitry is configured to: remove non-significant content from the component of the data item; generate a data item of a second data type from the sequentially received plurality of components; generate a hash of the generated data item; and provide the hash for signing.