Abstract: A technique for allowing a linear feedback shift register (LFSR), and particularly a Galois LFSR, to be advanced forward by an amount m (i.e. as if the register had undertaken m input/output cycles), without actually having to undertake m input/output cycles is described. This is useful for example in the communications domain by allowing the shift register to be able to jump to a particular scrambling code. In particular, an embodiment provides an apparatus which is able to control the advance of a LFSR by feeding into the LFSR a data word obtained from the polynomial multiplication of two predetermined data words which are looked up from one or more tables in dependence on an advance amount, being the number of steps the LFSR is to advance. The state of the LFSR after the data word has been fed into the LFSR is then the same state the LFSR would be in if it had actually been advanced by the advance amount.

Abstract: A method of distributing data between mobile devices while retaining control of that data. In particular, Digital Rights Management parameters are monitored and modified to control the distribution, and distribution is only permitted to devices which are approved or authorized. Mechanisms are provided for validating the identity of devices requesting transmission of the file.

Abstract: A technique for allowing a linear feedback shift register (LFSR), and particularly a Galois LFSR, to be advanced forward by an amount m (i.e. as if the register had undertaken m input/output cycles), without actually having to undertake m input/output cycles is described. This is useful for example in the communications domain by allowing the shift register to be able to jump to a particular scrambling code. In particular, an embodiment provides an apparatus which is able to control the advance of a LFSR by feeding into the LFSR a data word obtained from the polynomial multiplication of two predetermined data words which are looked up from one or more tables in dependence on an advance amount, being the number of steps the LFSR is to advance. The state of the LFSR after the data word has been fed into the LFSR is then the same state the LFSR would be in if it had actually been advanced by the advance amount.