Encryption device, decryption device, encryption method, decryption method, cryptography system, computer-readable recording medium storing encryption program, and computer-readable recording medium storing decryption program which perform error diagnosis

Abstract

In a cryptography system, plaintext storage unit stores a plaintext. Encryption unit encrypts the plaintext to generate a ciphertext. First verification data generating unit generates first verification data, and second verification data generating unit generates second verification data. Decryption unit decrypts the ciphertext to generate a decrypted plaintext. First verification unit performs verification using the decrypted plaintext and the first verification data. Second verification unit performs verification using the first verification data, the ciphertext, and the second verification data. Display unit displays the results of the verifications.