Patent ID: 8175266

Claim:
A method comprising: communicating, from an authenticating device to a client device, a mod value p and a range [α,β], wherein the range [α,β] comprises a series of values with a start value of α and an ending value of β, each value in the range having a size defined by a granularity ε, wherein α is greater than 0, wherein β is greater than 0, and wherein the granularity ε is greater than 1; receiving a check value y B , where y B is defined by steps comprising: initializing y B =0; for each value in the range [α,β], beginning with a current value x B equal to α and increasing by ε: calculating an intermediate check value z B , where z B for each x B in the range [α,β] equals the current value x B multiplied by an encrypted current value x B , shown as: z B =E(x B )*x B , wherein the encrypted current value x B is encrypted according to at least one of AES, DES and HMAC; performing a mod function on z B using the mod value p, shown as: z B =z B mod p; and updating the check value y B by adding the intermediate check value to a previous value of the check value, shown as: y B =y B +z B ; comparing the check value y B to an authentication value y A ; and upon the authenticating device determining that y B =y A , accepting the client device as authentic.