Improved data checking

摘要

There is provided a method and circuitry for modifying a message packet, the message packet comprising a plurality of sets of information bits constituting an information portion and a set of checking bits, all sets containing the same number of bits and each checking bit having been generated by taking the logical sum of bits in all of the sets having the same significance. The technique comprises modifying the message packet by deleting and/or adding a set of bits; and modifying the set of checking bits by taking the logical sum of the set of checking bits and the deleted and/or added set of bits. The technique further preferably includes encoding a sequence number of the packet in a message. The technique further comprises: determining the sequence number of the packet; converting the sequence number into a set of sequence bits having the same number of bits as the sets of information bits and the set of checking bits; and modifying the checking bits by taking the logical sum of the set of checking bits and the set of sequence bits.