Abstract: In the field of user authentication, the present invention provides an integrated system for the mutual authentication of a system database and a registered user with a view to increasing the security of remote authentication and the prevention of “phishing/man-in-the-middle” attacks, by one of several alternative means including Code matching, PIN verification, Image reproduction and recognition, Signature and personal data verification, DNA verification and Biometric verification, in each case by means of the differential between variable Codes computed at the database from data recorded for that user and at a remote terminal from replicate data retrieved from a data carrying device. The Codes are derived from the recorded data and a simple algorithm such that the Codes are not predicable.

Abstract: A payment card system for use in remote transactions wherein a cardholder may create additional accounts subsidiary to a principal payment card, each such account having its own unique payment card number compliant with existing standards and protocols and each credited in advance by transfer from the principal account with a specified amount available either to meet modest or mini payments below a specified level and otherwise only to meet the cost-of purchases from specified merchants, whilst disabling the principal payment card from being used in remote transactions, such that a variable payment card account number is used for each transaction, the principal payment card numbers are not at any time at risk, merchants may be certain of payment without possibility of repudiation of the transaction without needing to identify the cardholder, and thereby enabling remote anonymous transactions to take place both in the real world and in a virtual world.

Abstract: A method of authenticating users of controlled systems by providing for each registered user of the system to be required to produce an access code which varies for each user and for each occasion of use, by means of an account number, conventional fixed personal identification number and a random code grid matrix with embedded alphanumeric codes, in a preferred embodiment related to each weekday, date and month. The correct unique authentication code for any occasion for any registered user is known to a master computer system but may be produced by the registered user in a variety of ways, both online or in another interactive system and also directly from the code card without interactivity with the master system. The codes are randomly generated and therefore cannot be predicted as no pattern exists.