A method for executing a cryptographic calculation applied by a first processing unit, called client unit having a first datum (X') comprising a number n of indexed components and a second processing unit, called server unit, having at least one second datum, the units each comprising processing means (11, 21), the method comprising the secured evaluation of a function of two variables being written as a product of: - a sub-function f X of a first variable - a sub-function f Y of a second variable, and - a product of n indexed sub-functions f i of two variables, the evaluation being applied with the first (X') and the second datum as inputs of the function, the method being characterized in that it comprises the following steps: - randomly generating, by the server unit, a set of n invertible data for the multiplication, indexed r i belonging to the set with m being a prime number, - generating, by the server unit, for each i from 1 to n, a set for which each element is formed by the product of an indexed datum r i with a possible result of the sub-function of two variables f i evaluated at the first and the second datum, - applying an oblivious transfer protocol between the client unit and the server unit so that the client unit recovers, for each i from 1 to n, an intermediate datum t i equal to the result of the sub-function of two variables f i evaluated at the first (X') and the second data, multiplied by the indexed datum r i: t i = r i × f i x i, Y - multiplying, by the client unit, all the intermediate data and the sub-function of the first variable f X evaluated at the first datum (X') in order to obtain a result T: T = f X X ' × ∏ i = 1 n t i - generating, by the server unit, a result R equal to the product of all the reciprocals of the indexed data and of the sub-function of the second variable f Y evaluated at the second datum: R = f Y Y × ∏ i = 1 n r i − 1 - using the results T and R in a cryptographic application. - a sub-function f X of a first variable - a sub-function f Y of a second variable, and - a product of n indexed sub-functions f i of two variables, - randomly generating, by the server unit, a set of n invertible data for the multiplication, indexed r i belonging to the set with m being a prime number, - generating, by the server unit, for each i from 1 to n, a set for which each element is formed by the product of an indexed datum r i with a possible result of the sub-function of two variables f i evaluated at the first and the second datum, - applying an oblivious transfer protocol between the client unit and the server unit so that the client unit recovers, for each i from 1 to n, an intermediate datum t i equal to the result of the sub-function of two variables f i evaluated at the first (X') and the second data, multiplied by the indexed datum r i: t i = r i × f i x i, Y - multiplying, by the client unit, all the intermediate data and the sub-function of the first variable f X evaluated at the first datum (X') in order to obtain a result T: T = f X X ' × ∏ i = 1 n t i - generating, by the server unit, a result R equal to the product of all the reciprocals of the indexed data and of the sub-function of the second variable f Y evaluated at the second datum: R = f Y Y × ∏ i = 1 n r i − 1 - using the results T and R in a cryptographic application.