Method and apparatus for encrypting and decrypting information

Abstract

An encryption key is generated in response to a plurality of information pieces being bases for the encryption key. Original information is encrypted into encryption-resultant information in response to the generated encryption key. The encryption-resultant information is divided into units. Each of the units is loaded with encryption control information for identifying the plurality of information pieces being the bases for the encryption key.

1 - 7 . (canceled)  
   
   
       8 . A method of encrypting data with an encryption key, the data including at least one of audio data and video data, the method comprising the steps of: 
 dividing the data into units each corresponding to every prescribed number of successive packets conforming to the MPEG standards;    generating an encryption key from information pieces appointed for each of the units composing the data;    encrypting each of the units composing the data in response to the corresponding generated encryption key to generate a unit of encryption-resultant data;    generating encryption control information for appointing the information pieces used in generating the encryption key for each of the units composing the data; and    adding, to each of the units of the encryption-resultant data, the corresponding generated encryption control information.    
   
   
       9 . An apparatus for encrypting data with an encryption key, the data including at least one of audio data and video data, the apparatus comprising: 
 means for dividing the data into units each corresponding to every prescribed number of successive packets conforming to the MPEG standards;    means for generating an encryption key from information pieces appointed for each of the units composing the data;    means for encrypting each of the units composing the data in response to the corresponding generated encryption key to generate a unit of encryption-resultant data;    means for generating encryption control information for appointing the information pieces used in generating the encryption key for each of the units composing the data; and    means for adding, to each of the units of the encryption-resultant data, the corresponding generated encryption control information.