| CPC G06F 21/64 (2013.01) [G06F 11/3688 (2013.01)] | 6 Claims |

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1. A method for detecting data manipulation of numerical data values using a testing apparatus, which comprises the steps of:
initially ascertaining a Benford vector from frequencies, expected in accordance with a Benford distribution, of predefined leading digit groups in a transformation unit of the testing apparatus by way of a composition data transformation in a form of an isometric composition data transformation that maps the frequencies in relation to one another;
generating repeatedly randomly distributed numerical values using a random number generator of the testing apparatus and a plurality of simulation vectors being ascertained from the frequencies of the predefined leading digit groups of the randomly distributed numerical values by way of the transformation unit that carries out a same said composition data transformation as for the frequencies of the predefined leading digit groups;
ascertaining a simulation deviation from the Benford vector for each of the simulation vectors by means of a detection unit and being stored in a test memory of the testing apparatus;
subsequently reading in a group of numerical data values via an input interface of the testing apparatus;
ascertaining a test vector from the frequencies of the predefined leading digit groups in the numerical data values of the group by way of the transformation unit, and ascertaining a test deviation of the test vector from the Benford vector by the detection unit;
subsequently ascertaining a relative number of stored simulation deviations that are greater than the test deviation by way of a testing unit of the testing apparatus; and
outputting a positive manipulation value via an output interface if the relative number falls below a predefined threshold value.
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