Patent ID: 7251330

Claim:
A system for playing back encrypted content that is initially held in a first end-user device using a temporary playback end-user device, said system comprising: at least one portable cellular telephone that is authorized to obtain, from a content provider, the encrypted content and a token for decrypting the encrypted content; and a vehicle mounted playback unit associated with a unique digital signature, said vehicle mounted playback apparatus being the temporary playback end-user device; said at least one portable cellular telephone including: means for receiving, over a cellular telephone channel, an RF signal that includes the encrypted content and the token, means for establishing short distance wireless communication between said portable cellular telephone and said vehicle mounted playback apparatus, means for transmitting the encrypted content to said vehicle mounted playback unit using the short distance wireless communication, and means for transmitting, subsequent to said transmitting of the content, a content playback request and a content identifier associated with the transmitted content to the vehicle mounted playback apparatus using the short distance wireless communication; said vehicle mounted playback unit further including: means for storing the encrypted content, and means for transmitting, upon receiving the content playback request, a token delivery request that includes the unique digital signature associated with the vehicle mounted playback apparatus to the portable cellular telephone using the short distance wireless communication, the unique digital signature including a public key associated with the vehicle mounted playback apparatus; said at least one portable cellular telephone further including: means for authenticating the digital signature associated with the vehicle mounted playback apparatus, means for encrypting, using the public key associated with the vehicle mounted playback apparatus, the token when the digital signature of said vehicle mounted playback apparatus is successfully authenticated, and means for transmitting the encrypted token to the vehicle mounted playback unit using the short-distance wireless communication; said vehicle mounted playback unit further including: means for decrypting the encrypted token using a secret key associated with said vehicle mounted playback apparatus, means for temporarily storing the decrypted token; means for decoding the encrypted content using the decrypted token, a playback section for playing back the decrypted content; and means for automatically discarding the stored token upon playing back the decoded content or upon termination of the short distance wireless communication between said portable cellular telephone and said vehicle mounted playback apparatus, thereby preventing transfer of the token from said vehicle mounted playback apparatus.