Copy security for portable music players

A method for accessing subject data from a storage medium by a selected data access device, the method comprising:

• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to data secretly held by the selected data access device;
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the data secretly held by the selected data access device as an encryption key to form the subject data
• wherein the key identification data is formed from the encryption key;
• and
• wherein the encryption key is not directly determinable from data stored on the storage medium including the key identification data and the encrypted subject data.

A method for accessing subject data from a storage medium by a selected data access device, the method comprising:

• receiving key data corresponding to a second data access device from the second data access device;
• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to the key data received from the second data access device;
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the key data received from the second data access device as an encryption key to form the subject data.

A computer readable medium useful in association with a computer which includes a processor and a memory, the computer readable medium including computer instructions which are configured to cause the computer to bind subject data to a selected data access device such that the subject data is inaccessible to data access devices other than the selected data access device by:

• encrypting the subject data to form encrypted subject data using data corresponding to the selected data access device as an encryption key;
• forming key identification data from the encryption key;
• and
• storing the encrypted subject data and the key identification data in a storage medium which is readable by the selected data access device;
• wherein the encryption key is not directly determinable from data stored on the storage medium including the key identification data and the encrypted subject data.

A computer readable medium useful in association with a computer which includes a processor and a memory, the computer readable medium including computer instructions which are configured to cause the computer to access subject data from a storage medium by a selected data access device by:

• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to data secretly held by the selected data access device;
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the data secretly held by the selected data access device as an encryption key to form the subject data;
• wherein the key identification data is formed from the encryption key;
• and
• wherein the encryption key is not directly determinable from data stored on the storage medium including the key identification data and the encrypted subject data.

A computer readable medium useful in association with a computer which includes a processor and a memory, the computer readable medium including computer instructions which are configured to cause the computer to access subject data from a storage medium by a selected data access device by:

• receiving key data corresponding to a second data access device from the second data access device;
• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to the key data received from the second data access device;
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the key data received from the second data access device as an encryption key to form the subject data.

A computer system comprising:

• a processor;
• a memory operatively coupled to the processor;
• and
• a binding module (i) which executes in the processor from the memory and (ii) which, when executed by the processor, causes the computer to bind subject data to a selected data access device such that the subject data is inaccessible to data access devices other than the selected data access device by:
• encrypting the subject data to form encrypted subject data using data corresponding to the selected data access device as an encryption key;
• forming key identification data from the encryption key;
• and
• storing the encrypted subject data and the key identification data in a storage medium which is readable by the selected data access device;
• wherein the encryption key is not directly determinable from data stored on the storage medium including the key identification data and the encrypted subject data.

A computer system comprising:

• a processor;
• a memory operatively coupled to the processor;
• and
• a data access module (i) which executes in the processor from the memory and (ii) which, when executed by the processor, causes the computer to access subject data from a storage medium by a selected data access device by:
• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to data secretly held by the selected data access device;
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the data secretly held by the selected data access device as an encryption key to form the subject data;
• wherein the key identification data is formed from the encryption key;
• and
• wherein the encryption key is not directly determinable from data stored on the storage medium including the key identification data and the encrypted subject data.

A computer system comprising:

• a processor;
• a memory operatively coupled to the processor;
• and
• a data access module (i) which executes in the processor from the memory and (ii) which, when executed by the processor, causes the computer to access subject data from a storage medium by a selected data access device by:
• receiving key data corresponding to a second data access device from the second data access device;
• retrieving key identification data from the storage medium;
• determining that the key identification data corresponds to the key data received from the second data access device,
• retrieving encrypted subject data from the storage medium;
• and
• decrypting the encrypted subject data using the key data received from the second data access device as an encryption key to form the subject data.