Abstract: A hardware module has a plug to interface with an audio channel of a speech communication device. A scrambler connected to the plug is configured to receive a local audio input signal and form an encrypted audio output signal in a human audible range that is applied to the audio channel of the speech communication device. The scrambler also receives a remote encrypted audio input signal in a human audible range and forms a remote audio output signal corresponding to the remote encrypted audio input signal.

Abstract: In one embodiment, a non-transitory computer readable storage medium includes executable instructions to perform a series of operations represented by a first garbled program received from a client on garbled data received from the client. A second garbled program is obtained as a result of execution of the first garbled program. The second garbled program includes a first garbled portion and a second garbled portion. The second garbled portion includes a third garbled portion generated through execution of the first garbled portion, such that the series of operations can be performed without interaction with the client and while maintaining as hidden the underlying content of the first garbled program and the garbled data.

Abstract: instructions to: (1) process first data by encrypting based on a first key and re-arranging based on a first mapping to obtain second data, where a first element included in the first data is associated with a first index corresponding to a location in a first memory; (2) request to store the second data in a second memory at locations determined based on the first mapping; (3) in response to determining that the first element is not stored in the first memory, request a second element from the second memory; and (4) in response to determining that the first element is stored in the first memory: (a) retrieve the first element from the first memory; and (b) request a third element from the second memory that has not been previously requested, without requesting the second element from the second memory.