I’m curious about what the secret shared input for a garbled circuit is. Essentially, a garbled circuit is a two party computation framework where each of two players has each input as bit string. In this case where is secret shared input?

If there is a case when secret shared bit string is used as input, I want to know it’s mechanism and it’s reference material. Thanks


Normally the inputs to garbled circuits are known by the party who owns the input and are plaintexts.

There are scenarios in which the functionality (implemented by GC) needs to be evaluated on shared input. For example, if the two parties are not trusted with the plaintext input (may be owned by a third party) and instead only get shares of the input. The garbled circuit then consists of two sub-circuits: (1) the first sub-circuit combines the shares and recovers the secret input, and feeds it (without revealing it) to (2) the sub-circuit that implements the functionality to be evaluated on the secret input. At the end, the output is given to the parties (or if you want, you can append another circuit to split the output into two shares and give one share to each party)

  • $\begingroup$ Thank you for your answer!! That's interesting. Do you have some reference materials about this GC with Shared inputs? $\endgroup$ – mallea Nov 13 '18 at 15:15
  • $\begingroup$ One example protocol can be found here: eprint.iacr.org/2014/990 $\endgroup$ – Changyu Dong Nov 14 '18 at 16:57

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