A French computer programmer has landed himself in the soup, after designing a spoof credit card that could (The Guardian reports) "talk any cash terminal into handing him an unlimited supply of money". Serge Humpich, 36, was arrested when he offered his invention for £20 million to French banks. Humpich was in court on Friday, Jan 21, where the "procureur général" (i.e. state prosecutor, the French equivalent of a US district attorney) demanded a two-year suspended jail sentence along with FFr50,000 (roughly £5,000) in fines. Sentencing is due on February 25. Humpich's invention exploited flaws in the design of French electronic point of sale systems and could pick out all 35 million French PINs used on Visa and other credit cards. His discovery could also call into question the security of the smart card micro-chips used, until recently, in all French credit cards. New smart cards introduced by The GCB (Groupement des Cartes Bancaires) are supposed to be fool-proof. However the GCB's claim that smart cards are now 'bug free' amount to little more than hot air if the fault lies with the terminals. "I didn’t discover a crack in the system," Humpich said appearing in a Paris court (The Guardian reports). "I showed the card company managers that the entire system from A-Z was unsafe. The group which controls the use of credit cards did not believe me so I showed them I could fool any terminal by cracking the basic mathematical formula based on 96 numbers." Humpich is charged with using spoof credit cards to buy 10 Paris Metro tickets from an automatic dispenser. He made this transaction and then sent the receipt to the credit card company, to prove that his spoof card worked without being detected. The spoof credit card could not, as the The Guardian reported, "talk any cash terminal into handing him an unlimited supply of money": it worked only with terminals that did not send online referrals to the credit card network. So the card could be used only to buy cheap items (less than £10)-- hence the reason why Humpich bought Metro tickets to demonstrate his claims. Humpich was arrested in September 1999, three months after making contact with the credit card control group. He says he had no intention to steal, pointing out he could have posted his "crack" on the Internet, enabling other programmers to make their own credit cards from micro-chip-fitted blank cards. Also, by offering to provide the banks with a defence against the crack, Humpich was doing the honourable thing, his lawyer argues. The banks say different: "We consider the whole affair a form of blackmail, a spokesman told The Guardian. "We don’t believe he fabricated anything that endangered the security of our microchip cards. For two years he threatened a catastrophe that never came." Will Humpich’s defence wash? His argument (our paraphrase) -- "I am doing this merely to help companies improve their security" -- is used frequently by hacker sites, and sites which link to illegal WareZ retailers. But his £20 million price-tag for defending the security of the French credit card system is a complicating factor... other than that, he's really been duped by the Groupement des Cartes Bancaires. The only fraud he committed (buying subway tickets, to prove his point) was conducted at the invitation of GCB's attorneys, and most probably with the half-dozen virgin cards that GCB provided him with. ® So how did Humpich do it? This translated article from Parodie.com offers some pointers. Cédric Ingrand contributed to this article.