Computation of garbled tables in garbled circuit

A cost-effective method for generating a garbled circuit, the garbled circuit including a number of garbled gates having first and second garbled gate input wires, the garbled circuit incorporating encrypted information suitable for transmitting between a first communication device and a second communication device, the method comprising the steps of:

• providing a gate having first and second input wires and first and second keys on the first and second input wires, respectively;
• and
• generating a gate table with a PRFG algorithm, wherein the gate table includes four encryptions with a resulting key for each encryption equal to a function of the first and second keys of the first and second input wires.

A method for expediting encryption and decryption of a garbled circuit having a number of encryptions for a garbled table of a garbled gate comprising the steps of:

• forming the garbled table with a number of secret keys by applying a function to the secret keys to produce less than twice the number of secret keys as the number of encryptions for the garbled table;
• and
• evaluating the garbled table to decrypt an output key of the garbled table.