Abstract: A computer-implemented method of permitting authentication of data added to an initial plurality of unique data items stored on a computer, all of the data items being converted via a one-way function to respective equal length unique digests (or hashes); and the hashes being stored as a linked dataset in which the value of each successive hash is dependent on the value of the previous hash combined with a new hash resulting from the hashing of the most recently added data. The most recent hash in the linked dataset (hash chain) is the cumulative result of all previous hashes in their original sequence, each hash in the dataset being unique to the most recently added data. Each cumulative hash is constructed by incorporating one or more pre-existing cumulative hashes into the source data, before the new hash is calculated.

Abstract: A computer-implemented method of permitting authentication of data added to an initial plurality of unique data items stored on a computer, all of the data items being converted via a one-way function to respective equal length unique digests (or hashes); and the hashes being stored as a linked dataset in which the value of each successive hash is dependent on the value of the previous hash combined with a new hash resulting from the hashing of the most recently added data. The most recent hash in the linked dataset (hash chain) is the cumulative result of all previous hashes in their original sequence, each hash in the dataset being unique to the most recently added data. Each cumulative hash is constructed by incorporating one or more pre-existing cumulative hashes into the source data, before the new hash is calculated.

Abstract: Data is transmitted between a first user and a second user via an information technology communications network, in a method comprising the steps of: generating a first hash value for a selected one of the data items; digitally signing and encrypting the first hash value with a secret identifier associated with the first user; transmitting to a second user the encrypted first hash value; receiving and storing the transmitted encrypted first hash value for audit purposes and generating a second hash value for the received encrypted first hash value; encrypting the second hash value with a private identifier associated with a second user and a public identifier associated with the first user; and returning the encrypted second hash value to the first user.

Abstract: The various aspects of the present invention are based on four main principles: the provision, protection and validation of audit trails relating to data generated by and communicated between nodes of a network; authentication of communicating parties; enforcement of proof of receipt of data communications; and the detection of compromised user identifiers. The object of these principles being that, should a dispute arise over the substance of an authenticated e-mail or other data item, it would be possible to prove, with mathematical precision, the following features of the communication: the content of the message sent; the e-mail location to which the message was addressed; the fact that the message was despatched; the time and date of despatch; the fact that the message was received; the time and date it was received; and the fact that the content of the message had not been changed since it was sent.

Abstract: A system and method for authenticating a plurality of items each of which has a respective readable validation reference, in which information is read from the validation references, one or more items of the items is identified based on information read by the reading means, and the information is verified by comparison with stored data relating to location, origin or ownership of the one or more items.

Abstract: An authentication and/or tracking system for identifying, tracking, authenticating and/or otherwise checking the legitimacy of one or more items which include a coded identity tag or mark, the system comprising identification means for reading said coded identity tag or mark and identifying said one or more items, storage means for storing information relating to the location, whether actual or intended, origin and/or ownership of said one or more items, and means for displaying or otherwise providing or verifying said information relating to an item when its identity tag or mark has been read.