Signal protection and retrieval by non-linear analog modulation

A method for encryption and decryption of an analog message signal having a finite length from a beginning point thereof, comprising the steps of:

• encrypting the analog message signal with the steps of:
• processing the analog message signal through a first transfer function with the output thereof processed through a second transfer function, wherein each of the first and second transfer functions have at least a second order response,
• generating first and second analog key signals, each having a finite length from a beginning, the first analog key signal associated with the first transfer function and the second analog key signal associated with the second transfer function,
• parameterizing the first and second transfer functions with the associated and respective first and second analog key signals, and
• synchronizing the generation of the first and second analog key signals with the beginning of the analog message signal,
• wherein the output of the second transfer function provides an encrypted analog message signal having a finite length from a beginning;
• and
• decrypting the encrypted analog message signal from the step of encrypting with the steps of:
• processing the encrypted analog message signal through a third transfer function with the output thereof processed through a fourth transfer function, the third transfer function being the inverse of the first transfer function and the fourth transfer function being the inverse of the second transfer function,
• generating third and fourth analog key signals, each having a finite length from a beginning, the third analog key signal associated with the third transfer function and the fourth analog key signal associated with the fourth transfer function,
• wherein the third analog key signal is substantially identical to the first analog key signal and the fourth analog key signal is substantially identical to the second analog key signal,
• parameterizing the third and fourth transfer functions with the associated and respective third and fourth analog key signals, and
• synchronizing the generation of the third and fourth analog key signals with the beginning of the encrypted analog message signal,
• wherein the output of the second transfer function provides a decrypted analog message.

A processor for encryption/decryption of an analog message signal, wherein the analog signal has an associated length from a fixed beginning point, comprising:

• a message signal input for receiving the analog message signal;
• a first circuit for receiving the analog message signal and processing it with a first transfer function;
• a second circuit for receiving the output of the first circuit and processing it with a second transfer function;
• wherein each of the first and second transfer functions have at least a second order response;
• a first key input for receiving a first analog key signal for input to the first circuit, wherein the first transfer function in the first circuit is parameterized by the first analog key signal;
• a second key input for receiving a second analog key signal for input to the first second, wherein the second transfer function in the second circuit is parameterized by the second analog key signal;
• wherein each of the first and second analog key signals have a fixed beginning point and an associated length;
• and
• a controller for synchronizing the beginning of the received analog message signal with the beginning of the first and second analog key signals.