*"Is this obfuscation scheme unbreakable?"*

"Well.. no." said people a couple of years later.

1. On GGHRSW13 specifically: [Cryptanalyses of Candidate Branching Program Obfuscators](https://eprint.iacr.org/2016/998)

See also (concurrent, similar flavor):

2. [Cryptanalysis of Indistinguishability Obfuscations of Circuits over GGH13](https://eprint.iacr.org/2016/1003)

3. [Zeroizing Attacks on Indistinguishability Obfuscation over CLT13](https://eprint.iacr.org/2016/1011)

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Some interesting candidates for secure obfuscation do remain.

See, for instance,
[Secure Obfuscation in a Weak Multilinear Map Model](http://eprint.iacr.org/2016/817)