Patent ID: 7206748

Claim:
A computer readable medium containing program instructions for a software toolkit containing a collection of data structures and subroutines for developing an application for playing digital content data, the program instructions comprising instructions for: receiving previously encrypted content data encrypted with an encryption key from an external source; decrypting the received previously encrypted content data; reencrypting the decrypted received content data with a local encrypting key wherein the local encrypting key is a type of encryption key which enables streaming playback of the encrypted content while the encrypted content is being decrypted and without the need to first decrypt the entire encrypted content; storing the previously encrypted content data in a library; selecting one or more encrypted content data from the library to play; and decrypting each content data selected to bc played with its unique decryption key, wherein the decrypting is performed in a tamper-resistant subroutine for deterring unauthorized access to the instructions for decrypting the content data and for deterring unauthorized access to the decryption key; and; wherein the decrypting and reencrypting instructions are performed in the tamper resistance subroutine.