Testing method

Abstract

Testing whether a subject method has a constant processing time. The testing identifies a plurality of intermediate points in the subject method S40, wherein portions of the subject method performed between pairs of the intermediate points form a plurality of execution units of the subject method. The subject method is executed a plurality of times S42, where parameters are selected from first and second distributions S41, and measures execution times at which the subject method reaches each of the identified intermediate points S43. A statistical test is performed on the measured execution times to determine whether execution times S44, for a given execution unit of the subject method, is distinguishable between the executions in which the at least one parameter is selected from a first distribution and the executions in which the at least one parameter is selected from a second distribution. The subject method may be a cryptographic or machine learning method. Figure 4