Authentication method for authenticating a first party to a second party

An authentication system and method is presented for authenticating a first party to a second party, where an operation is performed on condition that the authentication succeeds. The authentication method verifies whether the first party is authenticated. If the first party is not authenticated, then it is determined if the first party qualifies for a sub-authorization. The sub-authorization depends on a value of a grace-counter associated with a number of times that first parties have been qualified for the sub-authorization. If the first party qualifies for the sub-authorization, the operation is performed and the grace counter is decremented. If the first party is authenticated, then the grace counter is set to a predetermined number

Method and apparatus for processing a signal using a digital processor having a given word length

A digital signal processor such as a watermark detector (12-18) operating with integer arithmetic circuits has a certain accuracy. Each processing step (multiplication, addition) increases the number of bits (the word length). For example, the Fast Fourier Transform (12) having a butterfly structure requires a plurality of such processing steps to be performed. In practical implementations, the processing steps are recursively performed by a single integer arithmetic circuit having a given word length, say N. After each step, the word length of the signal is reduced to the given word length N by rounding, truncation, or some other smart form of quantization. In order to prevent quantization errors, the signal is pre-processed by a pre-processor (19) which reduces the word length and which is invariant with respect to the subsequent process.; This means that if the pre-processor operated with infinite accuracy, it would have no effect on the subsequent process. If such a pre-processor operates with finite accuracy, it will reduce the quantization noise

Coulomb-Blockade Oscillations in Semiconductor Nanostructures

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