Encrypting method and apparatus, recording method, decrypting method and apparatus, and recording medium

A method of decrypting encrypted data that has been recorded on a recording medium, comprising the steps of:

• reproducing a first file from said recording medium, said first file containing said encrypted data, wherein said encrypted data has been encrypted by an encryption key and said encryption key is based on the wobbling frequency of a wobbled pre-groove and/or wobbled land portion of said recording medium;
• reproducing a second file containing data indicative of one or more positions on said recording medium;
• detecting the wobbling frequency of a wobbled pre-groove and/or wobbled land portion of said recording medium at each said position indicated by said second file;
• generating a decryption key based on said detected wobbling frequencies;
• and
• decrypting said encrypted data of said reproduced first file by using said decryption key.

A decrypting apparatus for decrypting an encrypted information recorded on a recording medium, comprising:

• a means for reproducing from a recording medium a first file storing information encrypted by using an encryption key generated based on a wobbling frequency of a predetermined portion of said information to be recorded on a recording medium and a second file storing data indicative of a predetermined portion of said encrypted information to be recorded on said recording medium;
• a means for detecting said wobbling frequency of a predetermined portion of said information stored in said reproduced first file based on said data stored in said reproduced second file and indicating said predetermined portion of said encrypted information;
• a means for generating a decryption key from said detected wobbling frequency;
• and
• a means for decrypting said encrypted information of said reproduced first file by using said decryption key.

A method of encrypting information to generate encrypted data and recording the encrypted data onto a recording medium, comprising the steps of:

• generating a first encryption key based on key data which is determined from said recording medium yet is not part of said encrypted data;
• generating a second encryption key based on said first encryption key and a third encryption key, which is independent of said first encryption key;
• and
• encrypting the information based on said second encryption key.

An apparatus for encrypting information to generate encrypted data and recording the encrypted data onto a recording medium, comprising:

• means for generating a first encryption key based on key data which is determined from said recording medium yet is not part of said encrypted data;
• means for generating a second encryption key based on said first encryption key and a third encryption key, which is independent of said first encryption key;
• and
• means for encrypting the information based on said second encryption key.

A method of decrypting encrypted data that has been recorded on a recording medium, comprising the steps of:

• generating a first decryption key based on key data which is determined from said recording medium yet is not part of said encrypted data, wherein said key data has been used to generate a first encryption key, said first encryption key has been used to generate a second encryption key, and said encrypted data has been encrypted using said second encryption key and a third encryption key, said third encryption key being reproduced from a key medium and being independent of said first encryption key;
• generating a second decryption key based on said first decryption key and a third decryption key, which is independent of said first decryption key;
• and
• decrypting said encrypted data by using said second decryption key.

An apparatus for decrypting encrypted data that has been recorded on a recording medium, comprising:

• means for generating a first decryption key based on key data which is determined from said recording medium yet is not part of said encrypted data, wherein said key data has been used to generate a first encryption key, said first encryption key has been used to generate a second encryption key, and said encrypted data has been encrypted using said second encryption key and a third encryption key, said third encryption key being reproduced from a key medium and being independent of said first encryption key;
• means for generating a second decryption key based on said first decryption key and a third decryption key, which is independent of said first decryption key;
• and
• means for decrypting said encrypted data by using said second decryption key.