| 摘要 |
For encryption, a random number (r) is generated, and encrypted text C2=M(+)R(r), a function value (HS(r, C2)), a common key (K), encrypted text (C(?+1)) of the random number (r) using the common key (K), and encrypted text (C(0), C(?)) of the common key (K) corresponding to the function value HS(r, C2) are generated. For decryption, a common key (K') is decrypted from inputted encrypted text (C'(0), C'(?)), inputted encrypted text (C'(?+1)) is decrypted using the common key (K') to generate a decrypted value (r'), and a function value HS(r', C2') is generated. If the inputted encrypted text (C'(0), C'(?)) does not coincide with encrypted text (C"(0), C"(?)) of the common key (K') corresponding to the function value HS(r', C2'), decryption is rejected, and if the inputted encrypted text (C'(0), C'(?)) coincides with the encrypted text (C"(0), C"(?)), inputted encrypted text (C2') is decrypted. |
