Method for authentication between two electronic devices

A method for authentication between first and second electronic devices, which comprises the steps of:

• a) generating at least one first and one second random number;
• b) transmitting the first and second random numbers so that both numbers are available in each of first and second electronic devices;
• c) encrypting the first random number to form a first cryptogram and encrypting the second random number to form a second cryptogram in the first and second electronic devices, each of the first and second cryptograms consisting of n parts, whereby n is an integer of two or greater;
• d) defining a counting index i=1;
• e) transmitting an ith part of the first cryptogram from the first to the second electronic device;
• f) comparing, in the second electronic device, the ith part of the first cryptogram transmitted in step e) with the ith part of the first cryptogram present in the second electronic device;
• g) if step f) does not result in a match, omitting steps h)-m) and continuing with step n);
• h) transmitting an ith part of the second cryptogram from the second to the first electronic device;
• i) comparing, in the first electronic device, the ith part of the second cryptogram transmitted in step h) with the ith part of the second cryptogram already present in the first electronic device;
• j) if step i) does not result in a match, omitting steps k)-m) and continuing with step n);
• k) ascertaining whether i=n;
• l) concluding the method for authentication if i=n, or continuing with step m) if i<n;
• m) defining i=i+1 and continuing at step e);
• and
• n) outputting arbitrary random numbers instead of further parts of the cryptograms, so that a point of termination due to a comparison which did not result in a match may not be ascertained from the outside.