An information processing device including: a protection control module operable to protect applications (110 - 114); the information processing device further comprising a plurality of detection modules (131 - 133); wherein the protection control module comprises: a decrypter operable to take an application in encrypted form as input data, to decrypt the input data, and to output decryption results as output data; a splitter operable to split the output data into at least k blocks (where k ≥ 2); and a distributor operable to distribute the k blocks and k pieces of block information among the detection modules (131 - 133), wherein a piece of block information corresponds to a block, and a piece of block information is distributed together with the corresponding block to a detection module (131 - 133); wherein each of the detection modules (131 - 133) comprises a verifier operable to determine whether or not each block distributed thereto is correct by using (i) the distributed block, (ii) verification data generated according to the input data and a block value expected to result from normal operation of the decrypter, and (iii) the input data; each of the detection modules (131 - 133) is operable (i) to obtain the respective pieces of block information distributed to other detection modules, and (ii) to confirm whether or not the verifier of each of the other detection modules has performed verification correctly according to the obtained pieces of block information; and when all the k blocks are distributed to one of the detection modules (131 - 133), each of the detection modules (131 - 133) other than the one detection module determines that tampering has occurred in the protection control module. a protection control module operable to protect applications (110 - 114); the information processing device further comprising a plurality of detection modules (131 - 133); wherein the protection control module comprises: a decrypter operable to take an application in encrypted form as input data, to decrypt the input data, and to output decryption results as output data; a splitter operable to split the output data into at least k blocks (where k ≥ 2); and a distributor operable to distribute the k blocks and k pieces of block information among the detection modules (131 - 133), wherein a piece of block information corresponds to a block, and a piece of block information is distributed together with the corresponding block to a detection module (131 - 133); wherein each of the detection modules (131 - 133) comprises a verifier operable to determine whether or not each block distributed thereto is correct by using (i) the distributed block, (ii) verification data generated according to the input data and a block value expected to result from normal operation of the decrypter, and (iii) the input data; each of the detection modules (131 - 133) is operable (i) to obtain the respective pieces of block information distributed to other detection modules, and (ii) to confirm whether or not the verifier of each of the other detection modules has performed verification correctly according to the obtained pieces of block information; and when all the k blocks are distributed to one of the detection modules (131 - 133), each of the detection modules (131 - 133) other than the one detection module determines that tampering has occurred in the protection control module. a decrypter operable to take an application in encrypted form as input data, to decrypt the input data, and to output decryption results as output data; a splitter operable to split the output data into at least k blocks (where k ≥ 2); and a distributor operable to distribute the k blocks and k pieces of block information among the detection modules (131 - 133), wherein a piece of block information corresponds to a block, and a piece of block information is distributed together with the corresponding block to a detection module (131 - 133); wherein each of the detection modules (131 - 133) comprises a verifier operable to determine whether or not each block distributed thereto is correct by using (i) the distributed block, (ii) verification data generated according to the input data and a block value expected to result from normal operation of the decrypter, and (iii) the input data; each of the detection modules (131 - 133) is operable (i) to obtain the respective pieces of block information distributed to other detection modules, and (ii) to confirm whether or not the verifier of each of the other detection modules has performed verification correctly according to the obtained pieces of block information; and when all the k blocks are distributed to one of the detection modules (131 - 133), each of the detection modules (131 - 133) other than the one detection module determines that tampering has occurred in the protection control module.