Method for combining transfer functions with predetermined key creation

• US 6,598,162 B1
• Filed: 03/24/1998
• Issued: 07/22/2003
• Est. Priority Date: 01/17/1996
• Status: Expired due to Term

• Current Assignee: Wistaria Trading Inc.
• Original Assignee: Wistaria Trading Inc.
• Inventors: Moskowitz, Scott A.
• Primary Examiner(s): Barron, Giberto
• Assistant Examiner(s): Meislahn, Douglas J
• Application Number:
  US09/046,627
• Time in Patent Office: 1,946 Days
• Field of Search: 713/176, 380/53, 380/54, 380/46, 708/254
• US Class Current: 713/176
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant

Abstract

A method for combining transfer functions with predetermined key creation. In one embodiment, digital information, including a digital sample and format information, is protected by identifying and encoding a portion of the format information. Encoded digital information, including the digital sample and the encoded format information, is generated to protect the original digital information. In another embodiment, a digital signal, including digital samples in a file format having an inherent granularity, is protected by creating a predetermined key. The predetermined key is comprised of a transfer function-based mask set to manipulate data at the inherent granularity of the file format of the underlying digitized samples.

Claims

1. A method for protecting a digital signal, comprising the steps of:

providing a digital signal comprising digital data and file format information;

creating a predetermined key that manipulates the file format information, said predetermined key comprising one or more mask sets having random or pseudo-random series of bits; and

validating the one or more mask sets and then manipulating the file format information using the predetermined key;

wherein the random or pseudo-random series of bits in said one or more mask sets is generated using a method comprising the steps of;

collecting an initial series of random bits derived from keyboard latency intervals in random typing;

processing the initial series of random bits through an MD5 algorithm;

using the results of the MD5 processing to seed a triple-DES encryption loop;

cycling through the triple-DES encryption loop, extracting the least significant bit each result after each cycle; and

concatenating the triple-DES output bits into the random or pseudo-random series of bits.