Since deciding that he had grown weary of penury as an academic, he has specialised in data security since 1982. His main area of expertise is in the development of specialist encryption and authentication software used in data security, and the evaluation of security products. After working for two specialist data security companies, he has been an independent security consultant since 1987, trading as Walsham Contracts, Ltd., and carrying out work for many of the major UK financial institutions (particularly in the field of EFTPOS), and developing specialist security products for several data security companies.

He currently contributes a monthly review article about anti-virus products to Virus Bulletin, and has written technical evaluation articles for many other security journals, including Computer Fraud and Security (an Elsevier publication), for which he provided a series of technical evaluations of computer security products. He is coco-author (with Dr. Jan Hruska) of The PC Security Guide, published by Elsevier, Oxford, U, and Computer Security Solutions, published by Blackwells, Oxford, UK. He is the author of Secure Information Transfer also published by Blackwells. Keith is a Chartered Physicist, a Member of the Institute of Physics, and a Member of the Biological Engineering Society. He spends far too little time engrossed in his first love: sailing.

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