Indistinguishability obfuscation

Indistinguishability obfuscation (IO) is a cryptographic primitive that provides a formal notion of program obfuscation. Informally, obfuscation hides the implementation of a program while still allowing users to run it.[1] A candidate construction of IO with provable security under concrete hardness assumptions relating to multilinear maps was published in 2013, but this assumption was later invalidated.[2][3] Work has continued attempting to establish preconditions from more standard assumptions, notably the 2020 work of Jain, Lin, and Sahai based on the XDH, LWE, and LPN assumptions.[3] However, none have achieved widespread acceptance to date, and the Jain, Lin, and Sahai proposal also requires the existence of a super-linear stretch pseudorandom generator in the function class NC⁰. The existence of any pseudorandom generators in NC⁰ (even with sub-linear stretch) was a long-standing open problem until 2006,[4] and the question of the existence of one with super-linear stretch is still open.