Patent ID: 7945046

Claim:
A decryption processing apparatus that decrypts encrypted digital data including an encrypted code and encrypted image data, the decryption processing apparatus comprising: a first decrypting section to apply a first decryption processing to the encrypted code so as to create a decryption diagnosis code from the encrypted code; a second decrypting section to apply a second decryption processing to the encrypted image data so as to generate decrypted image data from the encrypted image data; a decryption-processing determining section to determine whether or not the first decryption processing is normally achieved, based on the decryption diagnosis code created by the first decrypting section; and a control section comprising a CPU to control the second decrypting section, based on a result determined by the decryption-processing determining section; wherein (i) when the decryption-processing determining section determines that the first decryption processing is normally achieved, the control section allows the second decrypting section to commence an operation for applying the second decryption processing to the encrypted image data, and (ii) when the decryption-processing determining section determines that the first decryption processing is not normally achieved, the control section prohibits the second decrypting section from commencing the operation for applying the second decryption processing to the encrypted image data; wherein the encrypted code is acquired by encrypting a verification code, which serves as a decryption key for decoding the encrypted digital data; and wherein the decryption-processing determining section determines that the first decryption processing is normally achieved when a first decryption key, which was employed for the first decryption processing applied to the encrypted code by the first decrypting section, coincides with the decryption diagnosis code created by applying the first decryption processing.