An efficient public key traitor tracing scheme

We construct a public key encryption scheme in which there is one public encryption key, and many private decryption keys. If a broadcaster encrypts once with the public key, then each legitimate receiver can decrypt with a different private key. If a coalition of receivers collude to create a new decryption key then there is an efficient algorithm to trace the new key to its creators. Hence, our system provides a simple and efficient solution to the “traitor tracing problem”. Our tracing algorithm is deterministic, and catches all active traitors while never accusing innocent users, although it is only partially “black box”. A minor modification to the scheme enables it to resist an adaptive chosen ciphertext attack. Our techniques apply error correcting codes to the discrete log representation problem.

The most cited traitor tracing crypto-scheme versus… the Black Sunday hack:

Among the countermeasures he says he created was one known among pirates as the “Black Sunday” kill — an elaborate scheme that destroyed tens of thousands of pirate DirecTV cards a week before Super Bowl Sunday in 2001.

Instead of being delivered all at once like other measures, the Black Sunday attack code was sent to pirate cards in about five dozen parts over the course of two months, like a tank transported piece by piece to a battlefield to be assembled in the field. “They never expected us to do this,” Tarnovsky says.

Why stop at tracing traitors when you can wipe them out? Very clever.

Online behavioral advertising (OBA) refers to the practice of tracking users across web sites in order to infer user interests and preferences. These interests and preferences are then used for selecting ads to present to the user. There is great concern that behavioral advertising in its present form infringes on user privacy. The resulting public debate — which includes consumer advocacy organizations, professional associations, and government agencies — is premised on the notion that OBA and privacy are inherently in conflict.

Adnostic is a practical architecture that enables targeting without compromising user privacy. Behavioral profiling and targeting in Adnostic takes place in the user’s browser. The ad network remains agnostic to the user’s interests.

Our technical paper discusses the effectiveness of the system as well as potential social engineering and web-based attacks on the architecture. One complication is billing; ad-networks must bill the correct advertiser without knowing which ad was displayed to the user. We describe a cryptographic billing system that directly solves the problem. We implemented the core targeting system as a Firefox extension and report on its effectiveness.

If only Google were to implement this crypto-scheme…

The automatic exploit generation challenge is given a program, automatically find vulnerabilities and generate exploits for them. In this paper we present AEG, the first end-to-end system for fully automatic exploit generation. We used AEG to analyze 14 open-source projects and successfully generated 16 control flow hijacking exploits. Two of the generated exploits (expect‑5.43 and htget‑0.93) are zero-day exploits against unknown vulnerabilities. Our contributions are: 1) we show how exploit generation for control flow hijack attacks can be modeled as a formal verification problem, 2) we propose preconditioned symbolic execution, a novel technique for targeting symbolic execution, 3) we present a general approach for generating working exploits once a bug is found, and 4) we build the first end-to-end system that automatically finds vulnerabilities and generates exploits that produce a shell.

The first step to automatically search for and exploit the most basic vulnerabilities is done, and incremental improvements will surely follow. While this won’t have a deep impact on the computer security industry, since it’s already full of people exploiting software for free, it will surely have a real impact on the programming world: right now, all coders not acquainted with secure code-writing skills should be fired. For more information, visit the following link: Automatic Exploit Generation.