CN1909574A

CN1909574A - Multi-functional digital encrypting telephone

Info

Publication number: CN1909574A
Application number: CN 200610041168
Authority: CN
Inventors: 袁家斌; 高原
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2006-08-09
Filing date: 2006-08-09
Publication date: 2007-02-07

Abstract

The invention relates to a multifunctional digit encrypt telephone, which comprises a filter circuit, the first A/D-D/A converter, a coder/decoder, the second A/D-D/A converter, one power amplifier, a liquid crystal display module, DSP, a control panel, and a modulator/demodulator. The invention has the advantages that: a, it uses data encrypt technique to increase the security of telephone communication; b, it processes the sonic data of AMBE coder with one stat data compressor, to minimize the entropy abundance of sonic data, to reduce the code rate in sonic communication; c, it has special key identification system; d, it uses digit modulation and digit transmission techniques, to realize network access function of telephone, and the user can use network device to communicate with microphones via dialing number.

Description

Multi-functional digital encrypting telephone

Technical field

What the present invention relates to is a kind of multi-functional digital encrypting telephone, belongs to communication technical field.

Background technology

No matter the ordinary telephone set of Shi Yonging (its structure as shown in Figure 1) is traditional pulse, audio frequency compatible telephone machine now, or ISDN digital telephone set, or based on the IP phone of VOIP technology, what propagate on its communication line all is the analog or digital signal of plain code.Illegal wiretapping person only needs the communication terminal device that electric property is complementary is linked into just can the complete intercepting and capturing communication information on the legal communication line.

Summary of the invention

The present invention is to prevent that eavesdropping from being that purpose proposes a kind of multi-functional digital encrypting telephone.Transmission link at signal increases some functional units, as A/D converter, data compression unit, cryptographic algorithm unit, modulator-demodulator, decipherment algorithm unit, data decompression unit, D/A converter etc., by these functional units, the voice messaging of analog form is changed into the voice messaging of digital form, through being loaded on the AB line (telephone wire) by modulator-demodulator again after data compression and the data encryption.Upset and diffusion function because cryptographic algorithm has, make the voice messaging that is transmitted become to the eye random insignificant mess code information, allow the listener-in can't reach the purpose of monitoring, thereby realized information security and function of keeping secret.

Technical solution of the present invention; Its structure is to comprise filter circuit, an A/D, D/A converter, coding vocoder decoding unit, and the 2nd A/D, D/A converter, power amplification are clamored, LCD MODULE, DSP, control panel, modulator-demodulator.Annexation between them is the output of the input termination microphone of filter circuit, output termination the one A/D of filter circuit, the input of D/A converter, the one A/D, the input of the output termination coding vocoder decoding unit of D/A converter, output termination the 2nd A/D of coding vocoder decoding unit, the input of D/A converter, the output of coding vocoder decoding unit/go into first of termination DSP to import/go out to hold, second of DSP imports/goes out the output of termination LCD/go into end, the 3rd of DSP imports/goes out the output of termination modulator-demodulator/go into end, the 4th of DSP imports/goes out the output of termination control panel/go into end, the 2nd A/D, the input that the output termination power amplification of D/A converter is clamored, the output that power amplification is clamored connects acoustical generator, the input of the output of modulator-demodulator/go into terminated communications circuit/go out end.

Advantage of the present invention: a. introduces data encryption technology and has strengthened security of telephone communication greatly; B. the speech data with AMBE vocoder output uses the data compression unit of statistical method to handle by one again, makes the entropy redundancy of speech data reach minimum, thus the code check when further having reduced voice communication.C. Du Te key authentication system.D. owing to adopted digital modulation and demodulation, digital transmission technology, make confidential phone have network access facility.The terminal use can utilize the network equipment and speech ciphering equipments such as " headsets " to carry out secured telephony service by dial mode.

Description of drawings

Accompanying drawing 1 is the basic functional principle schematic diagram of existing telephone machine product.

Accompanying drawing 2 is system architecture diagrams of digital encrypting telephone.

Accompanying drawing 3 is basic embodiment block diagrams of digital encrypting telephone.

Accompanying drawing 4 is phonological component circuit theory diagrams.

Accompanying drawing 5 is that the TMS320F2812 chip integration has become hard-wired SPI serial line interface, the circuit theory diagrams that can be directly partly be connected with the host interface of AMBE2000.

Among the figure 1 is microphone, the 2nd, filter circuit, 3 is A/D, D/A converter (chip model AD73311), the 4th, digital speech codec unit (AMBE2000-10), 5 is the 2nd A/D, D/A converter (chip model AD73311), the 6th, power amplifier (LM386N-1), the 7th, LCD (the dot lcd display module M12864-7A4 of Truly company), the 8th, digital signal processor DSP (model: Texas Instruments TMS320F2812), the 9th, control panel, the 10th, modulator-demodulator (NI-EM56R-2, the main control chip of employing U.S. Rockwell (Conexant)), the 11st, communication line.

Embodiment

Contrast accompanying drawing 2, its structure comprise that filter circuit 2, an A/D, D/A converter 3, digital speech codec unit 4, the two A/D, D/A converter 5, power amplification clamor 6, LCD MODULE 7, DSP 8, control panel 9, modulator-demodulator 10.Annexation between them is the output of the input termination microphone 1 of filter circuit 2, output termination the one A/D of filter circuit 2, the input of D/A converter 3, the one A/D, the input of the output termination digital speech codec unit 4 of D/A converter 3, output termination the 2nd A/D of digital speech codec unit 4, the input of D/A converter 5, the output of coding vocoder decoding unit 4/go into first of termination digital signal processor DSP 8 to import/go out end, the output of termination LCD 7/go into end is imported/gone out to second of digital signal processor DSP 8, the output of termination modulator-demodulator 10/go into end is imported/gone out to the 3rd of digital signal processor DSP 8, the output of termination control panel 9/go into end is imported/gone out to the 4th of digital signal processor DSP 8, clamor 6 input of the output termination power amplification of the 2nd A/D conversion D/A device 5, clamor 6 output of power amplification connects acoustical generator, the input of the output of modulator-demodulator 10/go into terminated communications circuit 11/go out end.

The course of work: the voice signal that telephone receiver imports into converts digital signal to through an A/D, D/A converter 3 after being handled by filter circuit 2, by digital speech codec unit 4, code check is reduced significantly.Handle by digital signal processor DSP compression, cryptographic algorithm again, drop to the redundancy in the data minimum and be encrypted to ciphertext, and add error correcting code, by modulator-demodulator 10 data are sent at last.The modulator-demodulator of the other side's phone gets off Data Receiving, by digital signal processor DSP the data that receive is decrypted again, decompresses, and is reduced into sound by digital speech codec unit 4, the 2nd A/D, D/A converter 5 conversions and amplification again.

Phonetic algorithm adopts AMBE (Advanced Multi-Band Excitation) modified model to be with excitation algorithm more.So-called many band excitations are divided into several bands with speech manual by fundamental frequency exactly, and each band signal is judged voiced sound or voiceless sound respectively, be voiced sound or voiceless sound according to each band then, adopt different pumping signals to produce its composite signal,, form full band synthetic speech then with each band signal addition.

Contrast accompanying drawing 3, digital encrypting telephone adopts AMBE (Advanced Multi-Band Excitation) technology, that is: speech manual is divided into several bands by fundamental frequency, voiceless sound/voiced sound in the signal of each band (V, UV) is handled respectively, with each band signal stack, form full band synthetic speech at last.The process that is divided into two concurrent workings particularly: a.) send the words process as follows: by CPU control A/D converter, the voice signal of analog form is converted to the voice signal of digital form, form data flow, carry out the AMBE algorithm process by the vocoder in the coding vocoder decoding unit 4, then according to the cryptographic algorithm of setting (as the DES algorithm, RSA Algorithm, RKM algorithm etc.) data stream is encrypted, pass through the data compression unit in the digital signal processor DSP again, data flow is compressed into the bandwidth range that is suitable for modulator-demodulator (Modem) work, and the data flow after the compression is at last through being loaded on the telephone wire after the modulator-demodulator Modem modulation.B.) be subjected to the words process as follows: by being reduced into data flow after Modem the demodulates information that phone line is defeated, through the decipherment algorithm unit of flowing through behind the data decompression unit, CPU deciphers data flow according to the decipherment algorithm of setting, after handling through the AMBE vocoder again, form full band synthetic speech data flow, be reduced into the voice signal of analog form at last through D/A converter.

Need cipher key setting and authentication in the ciphering process: a.) authentication public key; B.) double-tone keeps pouring in defeated, affirmation; C.) authentication center.Authentication public key is similar to the SIM card authentication system, and key leaves in the SIM card, and this needs huge control data corporation, needs phone to increase card-reading function simultaneously, is not suitable for promoting in the starting stage.It is comparatively convenient that double-tone keeps pouring in is defeated, the affirmation mode implements.The calling party is when calling is connected for the first time with callee's (the calling and called both sides all install the digital encrypting telephone machine and open under the prerequisite of incoming call display function) foundation, by the CPU of calling party's confidential phone control Modem send a string double-tone frequently information (as " #*#*#*#* " etc.) give callee's telephone set, and oneself digital certificate passed to the callee with the other side's public key encryption, please the other side with the private key deciphering in order to confirm identity.After the other side confirmed, the CPU of callee's phone control Modem sent corresponding double-tone frequency information and postbacks the phone to the calling party, and postbacks the phone to the calling party behind the public key encryption of digital certificate with the calling party with oneself.The calling and called both sides have just confirmed identity like this.At this moment calling party's CPU working procedure produces a random number, with passing to the callee behind the other side's public key encryption.This moment the callee CPU also working procedure produce a random number, postback phone to the calling party behind the public key encryption with the calling party.The random number that random number that both sides' phone sends with the other side's phone and own CPU produce becomes the temporary key of this time conversing by unalterable rules.

Contrast Fig. 4, A/D converter and D/A converter (AD73311 chip), it is that 16 bit linear quantize the PCM codec, its sampling rate can reach 32kHz, 16 bit data, and has sound quality preferably, thereby can cooperate AMBE2000 to use.Peripheral circuit is made up of user interface circuit and microphone, receiver etc.User interface circuit is mainly realized by audio-frequency power amplifier (model LM386).

Contrast accompanying drawing 5, host machine part adopt 32 fixed point high speed digital signal processor DSP, maximum operating frequency 150M.Built-in 128K*16 position FLASH in the DSP sheet deposits user program, and FLASH can encrypt.Built-in 18K*16 position SRAM in the DSP sheet, the outer maximum of sheet can be expanded 512K*16 position SRAM.Satisfy the needs that voice are handled in real time.The TMS320F2812 chip integration has become hard-wired SPI serial line interface, directly partly is connected with the host interface of AMBE2000.All the operating voltage of device is 3.3V.

Data compression part: adopt the LZW data compression algorithm.Data encryption part: adopt the AES Advanced Encryption Standardalgorithm.Error correcting section: adopt Hamming code (Hamming Code) or BCH code.

Claims

1, multi-functional digital encrypting telephone is characterized in that comprising filter circuit, an A/D, D/A converter 3, digital speech codec unit, and the 2nd A/D, D/A converter, power amplification are clamored, LCD MODULE, DSP, control panel, modulator-demodulator; Annexation between them is the output of the input termination microphone of filter circuit, output termination the one A/D of filter circuit, the input of D/A converter, the one A/D, the input of the output termination digital speech codec unit of D/A converter, output termination the 2nd A/D of digital speech codec unit, the input of D/A converter, the output of coding vocoder decoding unit/go into first of termination digital signal processor DSP to import/go out end, the output of termination LCD 7/go into end is imported/gone out to second of digital signal processor DSP, the output of termination modulator-demodulator/go into end is imported/gone out to the 3rd of digital signal processor DSP, the output of termination control panel/go into end is imported/gone out to the 4th of digital signal processor DSP, the input of the output termination power amplifier of the 2nd A/D conversion D/A device, the output that power amplification is clamored connects acoustical generator, the input of the output of modulator-demodulator/go into terminated communications circuit/go out end.

2, multi-functional digital encrypting telephone according to claim 1, it is characterized in that by CPU control A/D converter, the voice signal of analog form is converted to the voice signal of digital form, form data flow, carry out the AMBE algorithm process by the vocoder in the coding vocoder decoding unit, then according to the cryptographic algorithm of setting (as the DES algorithm, RSA Algorithm, the RKM algorithm) data stream is encrypted, pass through the data compression unit in the digital signal processor DSP again, data flow is compressed into the bandwidth range that is suitable for modulator-demodulator work, data flow after the compression through being loaded on the telephone wire after the modulator-demodulator modulation, is finished the words process of sending at last; By being reduced into data flow after modulator-demodulator the demodulates information that phone line is defeated, through the decipherment algorithm unit of flowing through after the data compression unit in the digital signal processor DSP, CPU deciphers data flow according to the decipherment algorithm of setting (as DES algorithm, RSA Algorithm, RKM algorithm), after handling through the vocoder in the coding vocoder decoding unit again, form full band synthetic speech data flow, be reduced into the voice signal of analog form at last through D/A converter, finish the words process that is subjected to.

3, according to claim 1,2 described multi-functional digital encrypting telephones, it is characterized in that traffic encryption is to cipher key setting and authentication, described cipher key setting and authentication comprise it being authentication public key; Defeated, affirmation that double-tone keeps pouring in; Authentication center, wherein authentication public key is that key is left in the SIM card; That double-tone keeps pouring in is defeated, be confirmed to be the calling party with the callee set up call out for the first time be connected in, CPU control Modem by calling party's confidential phone sends the telephone set of a string double-tone frequency information to the callee, and oneself digital certificate passed to the callee with the other side's public key encryption, please the other side with the private key deciphering in order to confirm identity; After the other side confirmed, the CPU of callee's phone control Modem sent corresponding double-tone frequency information and postbacks the phone to the calling party, and postbacks the phone to the calling party behind the public key encryption of digital certificate with the calling party with oneself.