| 摘要 |
<p>The identity of a credit card user purchasing goods or services by telephone is verified with the help of a tones sender, issued by the credit cards company exclusively for each card, in which is registered a scrambled number derived from scrambling said ID number, and of a verifier device issued to the suppliers of the goods or services. When making a purchase, the card user communicates by telephone to the supplier his ID number. The tones sender emits a series of tones, the frequency of which is directly related to one digit of the scrambled ID number. The tones are transmitted through the telepone line. At the receiving end of the telephone line, the verifier device receives the series of audio tones, generates from them the scrambled ID number and performs an unscrambling process to reconstruct the unscrambled ID number. This latter is displayed and compared with the ID number communicated by the card user. If the two correspond, the identity of the card user is verified.</p> |
