Abstract: The invention provides a method for encrypting a program for execution on a remote host computer on a network, such that correct execution by the remote host computer is ensured, and such that the remote host computer remains unaware of the computations or data associated with execution. Results from the computations at the remote host computer are transmitted to a control computer, on the network, which decodes the results to useful data representative as output from the program. In a first step of the method, the program is encoded as a unitary matrix multiplication, Uij, of i dimensions by j dimensions. Un is the set of unitary matrices of size n, forms a non-commutative group under matrix multiplication, and has a unique group-invariant Haar measure probability distribution; Uij is thus an element of Un. In a second step, an input data string to the program is encoded as a vector bj of n dimensions. The first and second steps can be performed in either order.

Abstract: The invention provides a method for encrypting a program for execution on a remote host computer on a network, such that correct execution by the remote host computer is ensured, and such that the remote host computer remains unaware of the computations or data associated with execution. Results from the computations at the remote host computer are transmitted to a control computer, on the network, which decodes the results to useful data representative as output from the program. In a first step of the method, the program is encoded as a unitary matrix multiplication, Uij, of i dimensions by j dimensions. Un is the set of unitary matrices of size n, forms a non-commutatitive group under matrix multiplication, and has a unique group-invariant Haar measure probability distribution; Uij is thus an element of Un. In a second step, an input data string to the program is encoded as a vector bj of n dimensions. The first and second steps can be performed in either order.