Method and system for preventing unauthorized playback of broadcasted digital data streams

• US 6,530,021 B1
• Filed: 06/02/1999
• Issued: 03/04/2003
• Est. Priority Date: 07/20/1998
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Pasieka, Michael, Epstein, Michael
• Primary Examiner(s): Peeso, Thomas R.
• Application Number:
  US09/323,808
• Time in Patent Office: 1,371 Days
• Field of Search: 713/161, 713/168, 713/170, 713/176, 713/200, 713/201
• US Class Current: 713/176
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

A method and system are provided for preventing the unauthorized playback of broadcasted digital data streams. The method includes the step of embedding a watermark in a digital data stream. The digital data stream having the embedded watermark is encrypted. The encrypted digital data stream is broadcasted with a ticket. The encrypted digital data stream and the ticket are received. The ticket is saved and the encrypted digital data stream is provided to a decryption device to decrypt the digital data stream. The decrypted digital data stream is received from the decryption device. The watermark is extracted from the decrypted digital data stream. A one-way cryptographic hashing function is applied to the saved ticket. The hashed ticket-is compared to the extracted watermark. Playback of the digital data stream is prevented, when the hashed ticket does not match the extracted watermark.

Claims

1. A method for preventing unauthorized playback of digital data streams, comprising the steps of:

broadcasting an encrypted digital data stream with a ticket, the stream having a watermark embedded therein;

receiving the encrypted digital data stream and the ticket;

saving the ticket and providing the encrypted digital data stream to a decryption device to decrypt the digital data stream;

receiving the decrypted digital data stream from the decryption device;

extracting the watermark from the decrypted digital data stream;

applying a one-way cryptographic hashing function to the saved ticket;

comparing the hashed ticket to the extracted watermark; and

preventing playback of the digital data stream, when the hashed ticket does not match the extracted watermark.

2. A method for preventing unauthorized playback of digital data streams, comprising the steps of:

embedding a watermark in a digital data stream;

encrypting the digital data stream having the embedded watermark;

broadcasting the encrypted digital data stream with a ticket;

receiving the encrypted digital data stream and the ticket;

saving the ticket and providing the encrypted digital data stream to a decryption device to decrypt the digital data stream;

receiving the decrypted digital data stream from the decryption device;

extracting the watermark from the decrypted digital data stream;

applying a one-way cryptographic hashing function to the saved ticket;

comparing the hashed ticket to the extracted watermark; and

preventing playback of the digital data stream, when the hashed ticket does not match the extracted watermark.

3. The method according to claim 2, wherein said applying.step is performed more than once.

4. The method according to claim 2, further comprising the steps of:

generating the ticket by applying the one-way cryptographic hashing function to a sequence of numbers.

5. The method according to claim 4, wherein the one-way cryptographic hashing function is applied more than once to the sequence of numbers.

6. The method according to claim 2, further comprising the step of allowing playback of the digital data stream, when the hashed ticket matches the extracted watermark.

7. The method according to claim 2, further comprising the step of destroying the ticket.

8. A system for preventing unauthorized playback of broadcasted digital data streams, comprising:

a bus;

a conditional access module operatively coupled to said bus configured for decrypting encrypted digital data streams;

a receiver operatively coupled to said bus configured for receiving an encrypted digital data stream having a watermark embedded therein and a ticket, saving the ticket, providing the encrypted digital data stream to said conditional access module, and receiving a decrypted digital data stream from said conditional access module, the receiver comprising;

an extractor configured for extracting the watermark from the decrypted digital data stream;

a hashing module configured for applying-a one-way cryptographic hashing function to the saved ticket; and

a comparison module configured for comparing the hashed ticket to the extracted watermark; and

an inhibitor configured for preventing playback of the digital data stream when the hashed ticket does not match the extracted watermark.

9. The system according to claim 8, wherein said hashing module applies the one-way cryptographic hashing function to the ticket more than once.

10. The system according to claim 8, wherein said ticket is destroyed upon entering a power down mode.

11. The system according to claim 8, wherein said ticket is destroyed after a predetermined time period.