Re:Indistinguishability Obfuscation from Well-Founded Assump...
by sterlind on Tuesday November 10, 2020 @02:48PM
(#25050810)
Can you use iO to decrypt an FHE ciphertext and return an obfuscated output only if the ciphertext matches some value?
The iO circuit would need the FHE decryption key and the hidden output. If there were exactly one FHE ciphertext for any plaintext (which can't work, otherwise you could distinguish FHE values and break it), then you could simply implement this by supplying <target FHE ciphertext> XOR <obfuscated secret>.
Is there a scheme where iO could do this, or is it impossible because any obfuscation would necessarily require both the FHE decryption key and the obfuscated secret?
The iO circuit would need the FHE decryption key and the hidden output. If there were exactly one FHE ciphertext for any plaintext (which can't work, otherwise you could distinguish FHE values and break it), then you could simply implement this by supplying <target FHE ciphertext> XOR <obfuscated secret>.
Is there a scheme where iO could do this, or is it impossible because any obfuscation would necessarily require both the FHE decryption key and the obfuscated secret?