The problem
Imagine two programs that give exactly the same answers but use different instructions inside. Indistinguishability obfuscation, or iO, would transform them into working programs whose appearance does not let an efficient observer tell which original was used. Can this be achieved using only the noisy-equation assumption called Learning with Errors, with security even against quantum observers? The formal comparison uses circuits of the same size.[1] [2]
Swapping the two input wires of an AND gate leaves its truth table unchanged. Obfuscation asks whether an efficient observer can learn which equivalent implementation went into a transformer that preserves every output. Can ordinary LWE hardness alone support this guarantee against quantum attackers for general circuits?
For security parameter λ, the obfuscator must run in time polynomial in λ and circuit size, output an equivalent circuit, and make obfuscations of any efficiently specified same-size equivalent circuit pair computationally indistinguishable to quantum polynomial-time adversaries. Standard decisional LWE asks whether noisy modular inner products can be distinguished from uniform samples; its modulus, dimension, noise and required hardness must be specified.[1] [2]
Scope
In the standard model, construct a probabilistic polynomial-time indistinguishability obfuscator for all polynomial-size classical Boolean circuits, secure against quantum polynomial-time adversaries, from standard decisional Learning with Errors alone with explicitly stated parameters and hardness strength. Subexponential hardness is allowed; additional circular-security, auxiliary-hint or bilinear-group assumptions are outside this target.
What remains open
The missing reduction must use ordinary LWE without separately postulating security after circular encryptions or auxiliary openings are revealed. Permitting a stated subexponential LWE hardness level does not remove that distinction. Cryptanalysis of several earlier hint assumptions shows why a lattice-shaped assumption is not automatically a consequence of standard LWE.[1]
Why it matters
A convincing construction would show that hiding a program’s implementation can rest on the same kind of mathematical foundation as much lattice cryptography. That is a theoretical guarantee; it would not by itself make the resulting software small or fast.[1]
A successful reduction would explain how the extra information exposed by an obfuscated circuit can be simulated or controlled using LWE security. It would strengthen the theoretical basis of iO applications while leaving concrete implementation costs as a separate issue. The existing multi-assumption theorem remains an achieved result on that path.[1] [2]
Definitions
2 terms
Learning with Errors
A decisional hardness assumption: noisy modular linear samples should be hard to distinguish from uniform samples. Dimension, modulus, noise and the required hardness level must be specified; extra hints are not automatically included.[2]
Sources
- Lattice-Based Post-Quantum iO from Circular Security with Random Opening Assumption (Part II: zeroizing attacks against private-coin evasive LWE assumptions)
Notes on Lattice-Based Post-Quantum iO from Circular Security with Random Opening Assumption (Part II: zeroizing attacks against private-coin evasive LWE assumptions)
Abstract and Introduction define iO, explicitly leave standard LWE as the long-term goal, and distinguish the proposed CRO hint assumption from ordinary LWE.
- Indistinguishability Obfuscation from Well-Founded Assumptions
Notes on Indistinguishability Obfuscation from Well-Founded Assumptions
The author PDF dated November 12, 2020 states a construction from four subexponentially hard assumptions. This source credits conditional iO existence; it is not a construction from LWE alone.
- Indistinguishability Obfuscation from Well-Founded Assumptions (Journal of the ACM)
Notes on Indistinguishability Obfuscation from Well-Founded Assumptions (Journal of the ACM)
Primary indexed publisher metadata and abstract identify the February 2026 journal publication of a multi-assumption result. Direct journal full text was inaccessible; the accessible author manuscript supplies the scientific background.