A cryptographic processing apparatus comprising a cryptographic processing section that performs a Feistel-type common-key block-cipher process of repeating an SP-type F-function in a plurality of rounds, the SP-type F-function performing a data transformation process including a non-linear transformation process and a linear transformation process, wherein the cryptographic processing section is configured to perform a cryptographic process in which an extended Feistel structure having a number of data lines: d that is set to an integer satisfying d > 2 is applied, is configured to selectively apply a plurality of at least two or more different matrices in linear transformation processes that are performed in F-functions in respective rounds, the plurality of two or more different matrices being a plurality of different matrices satisfying a condition in which a minimum number of branches for all of the data lines is equal to or more than a predetermined value, the minimum number of branches for all of the data lines being selected from among minimum numbers of branches corresponding to the data lines, each of the minimum numbers of branches corresponding to the data lines being based on linear transformation matrices included in F-functions that are input to a corresponding data line in the extended Feistel structure, is configured so that the plurality of different matrices are repeatedly arranged in the F-functions that are input to the respective data lines in the extended Feistel structure; and wherein the plurality of different matrices, which are utilized in the cryptographic processing section, are a plurality of different matrices satisfying a condition in which a minimum number of branches (B k D, B 2 L) for all of the data lines is equal to or more than three, the minimum number of branches (B k D, B 2 L) for all of the data lines being selected from among minimum numbers of branches (B k D (s(i)), B 2 L (s(i))) corresponding to the data lines, each of the minimum numbers of branches (B k D (s(i)), B 2 L (s(i))) corresponding to the data lines being calculated on the basis of linear transformation matrices included in k, where k is an integer equal to or more than two, continuous rounds of F-functions that are input to a corresponding data line (s(i)) in the extended Feistel structure. a cryptographic processing section that performs a Feistel-type common-key block-cipher process of repeating an SP-type F-function in a plurality of rounds, the SP-type F-function performing a data transformation process including a non-linear transformation process and a linear transformation process, wherein the cryptographic processing section is configured to perform a cryptographic process in which an extended Feistel structure having a number of data lines: d that is set to an integer satisfying d > 2 is applied, is configured to selectively apply a plurality of at least two or more different matrices in linear transformation processes that are performed in F-functions in respective rounds, the plurality of two or more different matrices being a plurality of different matrices satisfying a condition in which a minimum number of branches for all of the data lines is equal to or more than a predetermined value, the minimum number of branches for all of the data lines being selected from among minimum numbers of branches corresponding to the data lines, each of the minimum numbers of branches corresponding to the data lines being based on linear transformation matrices included in F-functions that are input to a corresponding data line in the extended Feistel structure, is configured so that the plurality of different matrices are repeatedly arranged in the F-functions that are input to the respective data lines in the extended Feistel structure; and wherein the plurality of different matrices, which are utilized in the cryptographic processing section, are a plurality of different matrices satisfying a condition in which a minimum number of branches (B k D, B 2 L) for all of the data lines is equal to or more than three, the minimum number of branches (B k D, B 2 L) for all of the data lines being selected from among minimum numbers of branches (B k D (s(i)), B 2 L (s(i))) corresponding to the data lines, each of the minimum numbers of branches (B k D (s(i)), B 2 L (s(i))) corresponding to the data lines being calculated on the basis of linear transformation matrices included in k, where k is an integer equal to or more than two, continuous rounds of F-functions that are input to a corresponding data line (s(i)) in the extended Feistel structure.