Patent ID: 8233628

Claim:
An information processing apparatus comprising: at least one processor operatively coupled to a memory, serving as: an acquisition unit constructed to receive an input of first encrypted data generated by encrypting plaintext data using a first key according to a common key cryptography, and second encrypted data generated by encrypting the first key using the first key according to the common key cryptography, wherein the first encrypted data and second encrypted data are output from an encryption unit; a determination unit constructed to determine whether or not a second key matches second decrypted data which is generated by decrypting the second encrypted data using the second key according to the common key cryptography; and a decryption unit constructed to determine that the plaintext data can be obtained by decrypting the first encrypted data using the second key according to the common key cryptography and to decrypt the first encrypted data using the second key according to the common key cryptography when said determination unit determines that the second key matches the second decrypted data, and not to decrypt the first encrypted data using the second key according to the common key cryptography when said determination unit determines that the second key does not match the second decrypted data.