Obviousness

Obviousness Analysis under 35 U.S.C. § 103 for US7203844

This analysis evaluates whether the claims of US patent 7203844, "Method and system for a recursive security protocol for digital copyright control," would have been obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention, given the prior art identified in the "Prior art" section. The core inventive concept of US7203844's independent claims (Claims 1, 7, 14, and 20) revolves around a multi-layered or "recursive" encryption where not only the digital content (bit stream) is encrypted, but the decryption algorithm itself (or the combination of encrypted content and its algorithm) is subsequently encrypted with another layer, forming a nested security protocol.

Identified Prior Art References for Obviousness

1. U.S. Patent No. 6,327,652 (and other similar general encryption patents like U.S. Pat. Nos. 6,330,670, 6,412,070, 20020013772, 6,226,742, 6,101,605): These references generally disclose "basic operational categories of digital data encryption and decryption technologies" and "security protocols" for digital copyright control. They establish the foundational knowledge of encrypting digital content and associating it with a decryption method for access control.
2. "Architectural Support for Copy and Tamper-Resistant Software" by David Lie, et al. (ASPLOS-IX, 2000): This academic paper discusses architectural support for protecting software from unauthorized copying and tampering. It highlights the recognized problem in the art of securing software and digital content against sophisticated attacks and the need for robust, tamper-resistant mechanisms.
3. General knowledge in the art of cryptography and software engineering: This includes established principles such as:
   • The use of multiple, nested layers of encryption to enhance the security of sensitive data.
   • The fundamental understanding that software code, algorithms, and instructions are themselves digital data or "bit streams" that can be stored, transmitted, and thus subjected to cryptographic operations like any other digital content. Indeed, the patent itself defines a "bitstream" as "a stream of 1's and 0's" and states that "On a fundamental level, all binary digital data can be reduced to a stream of 1's and 0's (a bitstream), which can be stored and retrieved in a manner which is completely independent of the intended purpose or interpretation of that bitstream."

Obviousness Argument for US7203844 Claims

The independent claims of US7203844, exemplified by Claim 1 (method) and Claim 7 (system), describe a process where a first bit stream is encrypted and associated with a first decryption algorithm. This combination (the first encrypted bit stream and its decryption algorithm) is then itself encrypted, yielding a second encrypted bit stream associated with a second decryption algorithm. This second package is provided to a user for a two-step decryption process. Claims 14 and 20 describe a similar process utilizing a "data structure" to encapsulate the encrypted content and its decryption algorithm.

A PHOSITA in the field of digital rights management and security protocols, at the time of the invention (priority date June 20, 2002), would have been motivated to combine the known principles of encryption with the recognized need for enhanced security and tamper resistance, leading to the recursive protocol of US7203844.

Motivation for Combination:

1. Starting Point (General Encryption): A PHOSITA would begin with the established understanding of encrypting digital content and associating it with a decryption algorithm for controlled access, as broadly taught by patents like US 6,327,652. These systems provide basic copyright control.
2. Problem Recognition (Need for Enhanced Security): However, a PHOSITA would also be keenly aware of the limitations of single-layer encryption and the persistent challenge of protecting software and digital content from sophisticated attacks, including unauthorized copying and tampering. This problem is explicitly addressed in prior art such as the Lie et al. paper, which focuses on "Architectural Support for Copy and Tamper-Resistant Software." The patent itself states that "This invention relates to protecting digital content with a recursive security protocol which provides both greater security and greater flexibility than currently utilized methods." This clearly articulates the problem of improving existing security methods.
3. Applying Known Solutions (Layered Encryption and Data as Algorithms): To address the need for greater security and tamper resistance, a PHOSITA would naturally consider known methods for strengthening cryptographic protection. One fundamental and well-understood technique is to apply multiple, nested layers of encryption to particularly sensitive information. Furthermore, it is a basic tenet of digital systems that any algorithm or instruction set, whether for decryption or other purposes, is fundamentally represented as digital data—a "bit stream." The patent explicitly acknowledges this, stating, "On a fundamental level, all binary digital data can be reduced to a stream of 1's and 0's (a bitstream), which can be stored and retrieved in a manner which is completely independent of the intended purpose or interpretation of that bitstream."

Combining these elements, a PHOSITA would be motivated to:

• Take an initial digital content (first bit stream) and encrypt it, associating it with a first decryption algorithm, as commonly practiced in the art (e.g., from US 6,327,652).
• Recognizing that the decryption algorithm itself is a critical piece of digital information vulnerable to attack, and driven by the desire for enhanced tamper resistance and overall security (as emphasized by Lie et al.), the PHOSITA would logically seek to protect this decryption algorithm more robustly.
• Applying the known principle of layered encryption to this entire security package, it would be obvious to combine the first encrypted bit stream and its first decryption algorithm (potentially within a routine "data structure" for organized handling, as in Claim 14) and then subject this entire combination to a second layer of encryption. This action treats the entire initial security wrapper as a new "bit stream" to be further protected.
• The resulting "second bit stream" would then be associated with a "second decryption algorithm," the use of which would initiate the two-step recursive decryption process. The decryption steps are merely the logical inverse of the encryption process and would be obvious once the recursive encryption scheme is established.

This combination would yield a more resilient and flexible security protocol, addressing the recognized need for stronger digital copyright control and tamper-resistant software. The "recursive" nature of the protocol directly flows from the obvious application of layered security to all digital components requiring protection, including the protection mechanisms themselves. Therefore, the claimed invention, which essentially applies a well-known security enhancement (multi-layered encryption) to both content and its associated decryption instructions (understood as digital data), would have been obvious.