| 摘要 |
A cryptographic method comprising sequentially performing a number of rounds, each round comprising performing a respective round function on respective input data for that round to generate respective output data for that round, wherein for each of the second and subsequent rounds, the input data for that round is the output data of the preceding round, wherein for each round the respective round function comprises: applying a respective bijective operation to a first amount of data to produce a first result, the bijective operation corresponding to at least part of a cryptographic key; and processing a second amount of data by applying a plurality of processing operations to produce a second result, wherein at least one of the processing operations is the bijective operation; wherein the first amount of data and the second amount of data are based on the input for said round and wherein the output data for said round is based on the first result and the second result; wherein one or both of the following apply: (a) for each of one or more of the processing operations, that processing operation comprises functionality that is dependent on a respective part of the first result; and (b) for each of one or more of the processing operations, a number of times that processing operation is applied when processing the second amount of data is dependent on a respective part of the first result. |
