If achievable, Virtual Black Box (VBB) Obfuscation would prevent a program from leaking any information other than the data it delivers from its outputs. Unfortunately, a seminal paper published in 2001 showed that it is impossible to guarantee VBB obfuscation for every possible type of program.
In the same paper, though, the authors showed that a weaker form they called iO [indistinguishability obfuscation] was feasible. While iO does not promise to hide all the details of a logic circuit, as long as they are scrambled using iO, different circuits that perform the same function will leak the same information as each other; an attacker would not be able to tell which implementation is being used to provide the results they obtain.
—CACM, “Better Security Through Obfuscation”
In cryptography, Black-Box Obfuscation was a proposed cryptographic primitive which would allow a computer program to be obfuscated in a way such that it was impossible to determine anything about it except its input and output behavior. Black-box obfuscation has been proven to be impossible, even in principle.
Weaker variants: In their original paper exploring Black-Box Obfuscation, Barak et al. defined two weaker notions of cryptographic obfuscation which they did not rule out: indistinguishability obfuscation and extractability obfuscation (which they called “differing-inputs obfuscation”.)
—Wikipedia, “Black-box obfuscation”
In other words, while Virtual Black Box (VBB) Obfuscation is the objective, it is unattainable and Indistinguishability Obfuscation (iO) is the best alternative at this point in time.
Last year, three mathematicians published a viable method for hiding the inner workings of software. The paper was a culmination of close to two decades of work by multiple teams around the world to show that concept could work. The quest now is to find a way to make indistinguishability obfuscation (iO) efficient enough to become a practical reality.
Better Security Through Obfuscation Read More