Covert two-party computation

We introduce the novel concept of covert two-party computation. Whereas ordinary secure two-party computation only guarantees that no more knowledge is leaked about the inputs of the individual parties than the result of the computation, covert two-party computation employs steganography to yield the following additional guarantees: (A) no outside eavesdropper can determine whether the two parties are performing the computation or simply communicating as they normally do; (B) before learning f(xA, xB), neither party can tell whether the other is running the protocol; (C) after the protocol concludes, each party can only determine if the other ran the protocol insofar as they can distinguish f(xA, xB) from uniformly chosen random bits. Covert two-party computation thus allows the construction of protocols that return f(xA, xB) only when it equals a certain value of interest (such as "Yes, we are romantically interested in each other") but for which neither party can determine ...

• Type: Conference
• Year: 2005
• Where: STOC
• Authors: Luis von Ahn, Nicholas J. Hopper, John Langford
• Keywords: Algorithms, Computation Employs Steganography, Covert Two-party Computation, Decisional Diffie-Hellman Assumption, STOC 2005