Method and system for transferring information using an encryption mode indicator

A system for transferring information, said system comprising:

• a source device for encoding an encryption mode identifier (EMI) code into an information packet and for transmitting said information packet over a communication interface, said source device comprising:
• a common encryption circuit for encrypting data of said information packet based on a first key if said EMI code indicates a first mode, and wherein said common encryption circuit is also for encrypting data of said information packet based on a second key if said EMI code indicates a second mode;
• and
• a sink device for receiving said information packet from said communication interface, said sink device comprising:
• an extractor circuit for extracting said EMI code from said information packet;
• and
• a common decryption circuit is for decrypting said data of said information packet using said second key in response to said extractor circuit indicating that said EMI code is of said second mode;
• and
• wherein said first mode is a copy prohibition mode indicating that said information packet is not to be reproduced by said sink device and wherein said second mode is a copy once inhibition mode indicating that said information packet is not to be reproduced more than once by said sink device;
• and
• wherein said common decryption circuit of said sink device is also for decrypting said data of said information packet using said first key in response to said extractor circuit indicating that said EMI code is of said first mode;
• and
• wherein said source device and said sink device each comprise:
• a first hash circuit for generating said first key based on a common key;
• and
• a second hash circuit for generating said second key based on said common key and wherein said common key is transferred between said sink device and said source device before said information packet is received by said sink device.

A system for transferring information, said system comprising:

• a means for encoding an encryption mode identifier (EMI) code into an information packet and for transmitting said information packet over a communication interface, said means comprising:
• a first means for encrypting data of said information packet provided said EMI code indicates a first mode;
• and
• a second means for encrypting said data of said information packet provided said EMI code indicates a second mode;
• and
• a sink device for receiving said information packet from said communication interface, said sink device comprising:
• a means for extracting said EMI code from said information packet;
• and
• a first means for decrypting said data of said information packet in response to said means for extracting indicating that said EMI code is of said first mode;
• and
• a second means for decrypting said data of said information packet in response to said means for extracting indicating that said EMI code is of said second mode;
• and
• wherein said first mode is a copy prohibition mode indicating that said information packet is not to be reproduced by said sink device and wherein said second mode is a copy once inhibition mode indicating that said information packet is not to be reproduced more than once by said sink device;
• and
• wherein said first means for encryption, said second means for encryption, said first means for decryption and said second means for decryption are coupled to receive a same cipher key.