Patent ID: 11936780
Assignee: CABLE TELEVISION LABORATORIES, INC.
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method performed by a first computer in communication with a second computer, comprising:
transmitting, to the second computer, an initial vector {right arrow over (B)}=(B1, B2, . . . , BN) having N elements, the jth element Bj of the initial vector {right arrow over (B)} equaling (i·j·r)ymod p, wherein:
r is a first value that is known to the first computer and unknown to the second computer;
y is a first secret key that is known to the first computer and unknown to the second computer;
p is a large prime number that is known to both the first and second computers;
i is an increment that is a positive integer;
N is a positive integer; and
j is an index running from 1 to N;

receiving, from the second computer, a transformed vector {right arrow over (B)}*=(B1*, B2*, . . . , BN*) having N elements, the jth element Bj* of the transformed vector {right arrow over (B)}* equaling (Bi)xmod p, wherein:
x is a second secret key that is known to the second computer and unknown to the first computer; and

receiving, from the second computer, a third value a*=axmod p, wherein:
a is a second value that is known to the second computer and unknown to the first computer;

determining if the first value r is less than the second value a by determining if a fourth value a**=(a*)ymod p equals one of the N elements of the transformed vector {right arrow over (B)}*; and
completing an agreement between the first and second computers in response to the first value r being less than the second value a.