Signal protection and retrieval by non-linear analog modulation
A method is disclosed wherein an analog message signal is received with a finite length. An analog key signal is also received having a finite length at least as long as the analog message signal. An encryption carrier is generated and then an encryption operation initiated to encrypt the analog message. First, the encryption carrier is modulated with the analog key signal, generating an encryption dynamic carrier. Then, the analog message signal is mixed with the encryption dynamic carrier, with the mixing process initiated at an initial key starting point of the analog key signal and an initial message starting point. An encrypted message signal is output from the mixing process, which encrypted message signal has a starting point that coincides with both the message starting point and the key starting point and an encrypted message end point coinciding with the encrypted message signal end point.
1 . A method for encrypting a message, comprising the steps of:
receiving an analog message in an analog domain, the analog message to be encrypted and having a first length and initiated at a first time;
receiving an analog key signal in the analog domain having a second length equal to or greater than the first length, wherein the analog key signal is initiated at the same time as the analog message;
generating a reference sinusoidal signal having a reference frequency;
combining the reference sinusoidal signal and the analog message with a first combiner;
modifying the combined reference sinusoidal signal with the analog key signal which causes the spectral energy of the reference sinusoidal signal to be centered around the reference frequency; and
outputting from the combiner an encrypted message generated based on the modification of the combined reference sinusoidal signal.
2 . The method of claim 1 , wherein the reference sinusoidal signal is modulated with a modulator and the received analog key signal provides the input to the modulator.
3 . The method of claim 2 , wherein the modulator is operated by a modulation selected from the group consisting of phase modulation, frequency modulation and amplitude modulation.
4 . The method of claim 1 , wherein the combiner is a mixer.
5 . The method of claim 1 , wherein the combiner is a multiplier.
6 . The method of claim 1 , wherein the reference sinusoidal signal comprises a carrier centric signal that can be transmitted over a communication link.
7 . The method of claim 1 , wherein the reference frequency of the reference sinusoidal signal is above the frequency range of the analog key signal.
8 . The method of claim 1 , wherein the analog key signal is non periodic.
9 . The method of claim 8 , wherein the analog key signal is a continuous analog signal.
10 . A method for decrypting a complex analog encrypted message that was encrypted in an encryption process, the complex analog encrypted message encrypted with an analog key signal in an analog domain, the complex analog encrypted message having a finite length equal to or greater than the length of the analog message that was encrypted, comprising the steps of:
receiving the complex analog encrypted message in the analog domain to be de-crypted and having a first length and initiated at a first time;
receiving an analog key signal in the analog domain having a second length equal to or greater than the first length identical to the analog key signal utilized in the encryption process, wherein the received analog key signal is initiated at the same time as the complex analog encrypted message;
generating a reference sinusoidal signal having a reference frequency;
combining the reference sinusoidal signal and the complex analog encrypted message with a first combiner;
modifying the combined reference sinusoidal signal with the received analog key signal which causes the spectral energy of the reference sinusoidal signal to be centered around the reference frequency; and
outputting from the combiner a decrypted message generated based on the modification of the combined reference sinusoidal signal.
11 . The method of claim 10 , wherein the reference sinusoidal signal is modulated with a modulator and the received analog key signal provides the input to the modulator.
12 . The method of claim 11 , wherein the modulator is operated by a modulation selected from the group consisting of phase modulation, frequency modulation and amplitude modulation.
13 . The method of claim 10 , wherein the combiner is a mixer.
14 . The method of claim 10 , wherein the combiner is a multiplier.
15 . The method of claim 10 , wherein the reference sinusoidal signal comprises a carrier centric signal that is identical to a carrier centric signal utilized in the encryption process to generate the complex analog encrypted message.
16 . The method of claim 10 , wherein the reference frequency of the reference sinusoidal signal is above the frequency range of the analog key signal.
17 . The method of claim 10 , wherein the analog key signal is non periodic.
18 . The method of claim 17 , wherein the analog key signal is a continuous analog signal.