| 摘要 |
The invention relates to a method of obtaining through a first entity a derived value Kr. on the basis of an input parameter r. Said method comprises the following steps: the determination, as a function of said input parameter r, of a list of indices (i1,i2,..., iu), where u = l, in a predetermined list of indices, by means of a predetermined function for selecting indices E(r); and obtaining the said derived value Kr by applying, as a function of said input parameter r, a predetermined combining function Fr. to a set of blocks (Ti1,Ti2,...,Tiu) read from a predetermined table T of blocks Ti, where each of said blocks Ti has been generated by a second entity by means of a pseudo-random construction function GS(i) parameterized by a master value S that is not disclosed to said first entity. Application to encryption and authentication. |
