Secure credit card employing pseudo-random bit sequences for authentication

A secure credit card, comprising:

• a) a virtually emulated first linear-feedback shift register (LFSR);
• b) a second linear-feedback shift register (LFSR) or a second virtually emulated LFSR;
• and
• c) a clock for driving the first and second linear-feedback shift registers, wherein the clock is operable for an unpredictable number of cycles, wherein the unpredictable number of cycles is determined by a human action of unpredictable duration.

A method for authenticating a secure credit card having a linear feedback shift register (LFSR), comprising the steps of:

• a) sending from the credit card to a financial institution a card identification number uniquely associated with LFSR settings;
• c) sending from the financial institution to the credit card a request for an output of the LFSR after m clock cycles;
• d) operating the LFSR for m clock cycles to produce an LFSR output;
• e) sending the LFSR output from the card to the financial institution;
• f) comparing the LFSR output with LFSR settings for the credit card to authenticate the credit card.