Variable time inversion algorithm controlled system for multi-level speech security

Claim 3

The method as defined in claim 1 further comprising the step of delaying each of said conversion and deconversion steps by one sample period, whereby the analog speech is delayed by two sample periods relative to said input signal.

Claim 4

The method as defined in claim 2 further comprising the steps of converting said analog speech input signal to a digital signal prior to time inversion scrambling and converting the resulting digital time inverted signal to an analog signal prior to transmission to the receiver.

Claim 5

The method as defined in claim 3 further comprising the steps of converting the time inverted analog signal to a digital signal prior to descrambling and converting the resulting digital descrambled signal to an analog signal corresponding to said input signal.

Claim 6

The method as defined in claim 4 further comprising the step of varying said sampling period and said synchronization and delay steps to provide several levels of scrambling.

Claim 7

The method as defined in claim 5 wherein said synchronization step includes sub-audible tone identification.

Claim 8

The method as defined in claim 5 wherein said synchronization step includes sequential tone identification.

Claim 9

The method as defined in claim 5 wherein said synchronization step and said sampling period is altered to provide additional scrambling levels.

Claim 11

The method as defined in claim 1 wherein said sep of scrambling said digitized multibit word audio signals further includes the step of scrambling digital data signals.

Claim 12

The method as defined in claim 1 or 10 further comprising the step of utilizing the multiplexing facilities of said digital serial interface to provide for an additional level of encryption of said digitized scrambled multibit audio word signals.

Claim 13

A multilevel method for the encryption of data, speech or a combination thereof with other information comprising: (a) converting audio signals into digitized multibit word signals in a first microcomputer for a sample period; (b) scrambling said digitized multibit word signals through algorithms provided by software in said first microcomputer to provide encrypted multibit audio word digital signals; (c) generating parallel supervisory multibit word digital signals to affect synchronization and corrective control of said encrypted multibit word signal; (d) multiplexing, serializing and communicating said encrypted multibit audio word signals together with said parallel supervisory multibit word digital signals over a digital serial interface having software controlled pulse code modulation and time division multiplexing facilities to a second microcomputer; (e) demultiplexing and deserializing said encrypted multibit audio word signals and said supervisory multibit word signals through a reverse process utilizing said second microcomputer in conjunction with a codec for converting said scrambled digitized multibit audio word signals into scrambled analog audio; (f) operating said first microcomputer in conjunction with a codec and said second microcomputer and a microcomputer in a remote receiving two way radio to provide a deconversion of scrambled analog audio into unscrambled audio signals; and (g) processing said supervisory multibit word digital signals with said microcomputer in said remote receiving two way radio to provide synchronization and corrective control to provide an accurate reproduction of said audio signals.

Claim 14

A multilevel method for the encryption of data, speech or a combination thereof with other information comprising: (a) converting audio signals into digitized multibit word signals in a first microcomputer for a sample period; (b) scrambling said digitized multibit word signals through algorithms provided by software in said first microcomputer to provide encrypted multibit audio word digital signals; (c) generating parallel supervisory multibit word digital signals to affect synchronization and corrective control of said encrypted multibit word signal; (d) multiplexing, serializing and communicating said encrypted multibit audio word signals together with said parallel supervisory multibit word digital signals over a digital serial interface having software controlled pulse code modulation and time division multiplexing facilities to a second microcomputer; (e) demultiplexing and deserializing said encrypted multibit audio word signals and said supervisory multibit word signals through a reverse process utilizing said second microcomputer in conjunction with a codec for converting said scrambled digitized multibit audio word signals into scrambled analog audio; (f) operating said first microcomputer in conjunction with a codec and said second microcomputer and a microcomputer in a remote receiving two way radio to provide a deconversion of scrambled analog audio into unscrambled audio signals; and (g) processing said supervisory multibit word digital signals with said microcomputer in said remote receiving two way radio to provide synchronization and corrective control to provide an accurate reproduction of said audio signals.

Claim 15

The multilevel method of claim 12 further comprising the step of communicating digital multibit word signals corresponding to digital data over said digital serial interface.

Claim 16

The multilevel method of claim 13 further comprising the step of scrambling and unscrambling said digital multibit word signals corresponding to said digital data.

Claim 17

The multilevel method of claim 12 or 13 further comprising the step of utilizing different algorithms to vary the sample period, alter the system synchronization, vary a time delay or provide frequency scrambling in said scrambling and descrambling steps to further vary the levels of security.

Claim 18

A multilevel method for the encryption and transmission of data, speech or a combination thereof with other information comprising: (a) converting audio signals in a transmitting two-way radio into digitized multibit word signals for a sample period by utilizing a first microcomputer in a control unit side of said two way radio; (b) inputing digitized multibit word signals corresponding to digital data; (c) scrambling said digitized audio multibit word signals or said digitized multibit word signals corresponding to digital data or a combination thereof through algorithms provided by the software of said first microcomputer to produce digitized scrambled multibit word signals and generating parallel supervisory/synchronization multibit word digital signals utilizing said first microcomputer and said software; (d) multiplexing, serializing and communicating said digitized scrambled multibit word signals and said parallel supervisory/synchronization multibit word digital signals sequentially over a digital serial interface having software controlled pulse code modulation and time division multiplexing facilities to a radio frequency unit of said transmitting two way radio having a second microcomputer; (e) demultiplexing and deserializing said digitized scrambled multibit word signals and said supervisory/ synchronization multibit word digital signals through a reverse process in the radio frequency unit of the digital serial interface utilizing said second microcomputer in said radio frequency unit; utilizing said second microcomputer operating in conjunction with a codec to convert scrambled multibit word signals into scrambled analog audio and data for transmission over the air by said transmitting two way radio; said second microcomputer operating in conjunction with a microcomputer in a radio frequency unit in a similar receiving remote two way radio for deconverting said digital signals by reverse algorithm to provide the deconversion of audio into unscrambled analog speech or for unscrambling said scrambled digital signals corresponding to digital data; and (f) processing said supervisory/synchronization multibit word digital signals by said second microcomputer in said radio frequency unit of said similar receiving remote two way radio to affect corrections or synchronization by communicating in a reverse process to said first microcomputer in said control unit of said transmitting two way radio and synchronizing overall said conversion and deconversion steps at said similar receiving remote two way radio to provide an accurate reproduction of the encrypted digital data or audio signals.

Claim 19

A multilevel method for the encryption and transmission of data, speech or a combination thereof with other information comprising: (a) converting audio signals in a transmitting two-way radio into digitized multibit word signals for a sample period by utilizing a first microcomputer in a control unit side of said two way radio; (b) inputing digitized multibit word signals corresponding to digital data; (c) scrambling said digitized audio multibit word signals or said digitized multibit word signals corresponding to digital data or a combination thereof through algorithms provided by the software of said first microcomputer to produce digitized scrambled multibit word signals and generating parallel supervisory/synchronization multibit word digital signals utilizing said first microcomputer and said software; (d) multiplexing, serializing and communicating said digitized scrambled multibit word signals and said parallel supervisory/synchronization multibit word digital signals sequentially over a digital serial interface having software controlled pulse code modulation and time division multiplexing facilities to a radio frequency unit of said transmitting two way radio having a second microcomputer; (e) demultiplexing and deserializing said digitized scrambled multibit word signals and said supervisory/ synchronization multibit word digital signals through a reverse process in the radio frequency unit of the digital serial interface utilizing said second microcomputer in said radio frequency unit; utilizing said second microcomputer operating in conjunction with a codec to convert scrambled multibit word signals into scrambled analog audio and data for transmission over the air by said transmitting two way radio; said second microcomputer operating in conjunction with a microcomputer in a radio frequency unit in a similar receiving remote two way radio for deconverting said digital signals by reverse algorithm to provide the deconversion of audio into unscrambled analog speech or for unscrambling said scrambled digital signals corresponding to digital data; and (f) processing said supervisory/synchronization multibit word digital signals by said second microcomputer in said radio frequency unit of said similar receiving remote two way radio to affect corrections or synchronization by communicating in a reverse process to said first microcomputer in said control unit of said transmitting two way radio and synchronizing overall said conversion and deconversion steps at said similar receiving remote two way radio to provide an accurate reproduction of the encrypted digital data or audio signals.

Claim 20

The multilevel encryption method of claim 16 wherein parallel multibit words for command and status are also applied to the digital serial interface at the control unit and radio frequency portions of said two way radio said multibit words for command and status being bidirectionally and sequentially communicating across the digital serial interface in series with digitized audio word signals and digital supervisory/synchronization signals to allow control of other radio function sin addition to encryption/decryption.

Claim 21

The multilevel encryption method of claim 16 further comprising the step of time shifting audio digital signals alone or in combination with digital data signal in said encryption step and producing decryption through reshifting to normal time sequence through reverse algorithms.

Claim 22

The multilevel encryption method of claim 16 further comprising the step of employing subaudible tones to provide identification or synchronization of the encryption level.

Claim 23

The multilevel encryption method of claim 19 wherein said step of employing subaudible tones utilizes a sequential tone.