A conversion device (26; 1526) for converting input data into an input format suitable for a secure computation comprising: an acquisition unit configured to acquire an object data on which the secure computation is to be performed and to acquire request condition data indicating the conditions of the secure computation requested by a user; a storage unit configured to store a correspondence table specifying an input format of an encryption method required for executing the secure computation, the correspondence table including an algorithm correspondence table and a score correspondence table, wherein the algorithm correspondence table is a table obtained by associating information on machine learning algorithms with one or a plurality of encryption methods which can be combined with the machine learning algorithms, and the score correspondence table is a table associating scores with types of encryption method based on the conditions requested by the user; a conversion processing unit (120; 1520) configured to perform a conversion from the acquired object data into a secure computation data in accordance with the correspondence table, the conversion processing unit including a conversion unit and an encryption unit; and an output unit configured to output the secure computation data, wherein the request condition data includes a selective condition related to the secure computation and/or a plurality of evaluation conditions to which a score is given, the object data at least includes a second data which includes a machine learning model of a first data, and the second data includes a specification data of the machine learning model of the first data and parameter information, the specification data of the machine learning model and an input format of one or a plurality of encryption methods are associated with each other in the correspondence table, the conversion processing unit is configured to extract an input format corresponding to the specification data of the machine learning model from the stored correspondence table based on the algorithm correspondence table, the score correspondence table and the selective condition and/or the score contained in the request condition data, and to perform the conversion in accordance with the extracted input format, the conversion including converting the machine learning model into the extracted input format and encrypting the parameter information using the encryption method associated with the input format to generate encryption parameter information, and the specification data of the machine learning model includes information identifying an algorithm used in the machine learning model or AI source code based on a machine learning library. an acquisition unit configured to acquire an object data on which the secure computation is to be performed and to acquire request condition data indicating the conditions of the secure computation requested by a user; a storage unit configured to store a correspondence table specifying an input format of an encryption method required for executing the secure computation, the correspondence table including an algorithm correspondence table and a score correspondence table, wherein the algorithm correspondence table is a table obtained by associating information on machine learning algorithms with one or a plurality of encryption methods which can be combined with the machine learning algorithms, and the score correspondence table is a table associating scores with types of encryption method based on the conditions requested by the user; a conversion processing unit (120; 1520) configured to perform a conversion from the acquired object data into a secure computation data in accordance with the correspondence table, the conversion processing unit including a conversion unit and an encryption unit; and an output unit configured to output the secure computation data, wherein the request condition data includes a selective condition related to the secure computation and/or a plurality of evaluation conditions to which a score is given, the object data at least includes a second data which includes a machine learning model of a first data, and the second data includes a specification data of the machine learning model of the first data and parameter information, the specification data of the machine learning model and an input format of one or a plurality of encryption methods are associated with each other in the correspondence table, the conversion processing unit is configured to extract an input format corresponding to the specification data of the machine learning model from the stored correspondence table based on the algorithm correspondence table, the score correspondence table and the selective condition and/or the score contained in the request condition data, and to perform the conversion in accordance with the extracted input format, the conversion including converting the machine learning model into the extracted input format and encrypting the parameter information using the encryption method associated with the input format to generate encryption parameter information, and the specification data of the machine learning model includes information identifying an algorithm used in the machine learning model or AI source code based on a machine learning library.