Indistinguishability obfuscation from LWE

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Subjects: Cryptography

Collections: Limits of computation · Cryptography

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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]

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

One route combines several hardness assumptions. A post-quantum lattice proposal instead assumes that certain noisy samples remain secure when extra encrypted-data hints are opened. Neither supplies a reduction of general, quantum-secure iO to ordinary LWE alone.[1] [2]

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]

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]

computationally indistinguishable

An efficient observer cannot distinguish two families of outputs with a non-negligible advantage as the security parameter grows. This page requires that guarantee against quantum polynomial-time observers.[1] [2]

Sources

  1. Lattice-Based Post-Quantum iO from Circular Security with Random Opening Assumption (Part II: zeroizing attacks against private-coin evasive LWE assumptions) Yao-Ching Hsieh, Aayush Jain and Huijia Lin
    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.

  2. Indistinguishability Obfuscation from Well-Founded Assumptions Aayush Jain, Huijia Lin and Amit Sahai
    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.

  3. Indistinguishability Obfuscation from Well-Founded Assumptions (Journal of the ACM) Aayush Jain, Huijia Lin and Amit Sahai · 2026-02-12
    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.

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