CN101764871B

CN101764871B - Method for encrypting voice to transmit in PSTN network

Info

Publication number: CN101764871B
Application number: CN 200910263545
Authority: CN
Inventors: 梁鸿斌
Original assignee: CHENGDU 30RUITONG MOBILE COMMUNICATION Co Ltd
Current assignee: CHENGDU 30RUITONG MOBILE COMMUNICATION Co Ltd
Priority date: 2009-12-23
Filing date: 2009-12-23
Publication date: 2013-08-07
Anticipated expiration: 2029-12-23
Also published as: CN101764871A

Abstract

The invention discloses a method for encrypting voice to transmit in a PSTN network, comprising the steps that: at a transmitting end, the analog voice is processed by A/D conversion, then PCM data is compressed and coded by a vocoder, the coded data is encrypted, a message key is added, the coded data and the massage key are corrected and coded, the encrypted coded data, the massage key and error correction of coding are modulated into data similar to the voice, and the obtained data is transmitted on the PSTN network after D/A conversion; and at a receiving end, a signal is treated by A/D conversion, demodulated, corrected and decrypted, is then decoded by the vocoder and is treated by D/A conversion, and a simulated voice signal is output. The invention has the outstanding advantages of: breaking through the technical bottleneck that encrypted voice data can not be correctly restored into the voice data at the receiving end after being transmitted by the PSTN network, and guaranteeing the quality of encrypted voice by correcting the error code generated in the processes of modulation and transmission. The method does not need a MODEM chip and a peripheral circuit, and realizes the transmission of the encrypted voice in the PSTN network.

Description

The method that a kind of encrypted voice transmits in the PSTN net

Technical field

The present invention relates to the private communication technology field, be specifically related to the method that a kind of encrypted voice data is transmitted at PSTN on the net.

Background technology

The transmission encrypted voice has only a kind of mode at present in the PSTN net, namely after dial-up success, starts the MODEM chip and sets up data channel end to end, and after data channel was set up, encrypted voice data could begin to transmit.One of this mode shortcoming is to need MODEM chip and peripheral circuit, causes increasing the difficulty of cost and debugging; Another significant disadvantages, it is oversize to be that the MODEM chip is set up time of data channel, generally surpasses 18 seconds, user Come is said use extremely inconvenience.

Summary of the invention

The objective of the invention is to: a kind of method of transmitting encrypted voice in the PSTN net is provided, makes in this way, its ease for use is greatly improved, and has reduced cost and debugging difficulty significantly.

The objective of the invention is to realize by enforcement following technical proposals Come:

The method that a kind of encrypted voice transmits in the PSTN net, step is as follows:

One, at transmitting terminal:

1, by the A/D converter analogue voice signal is transformed into the PCM data-signal;

2, by vocoder PCM data-signal compressed encoding is become vocoder data;

3, encrypt described vocoder data and increase the message transfer key by CPU;

4, by CPU vocoder data and message key after encrypting are carried out error correction coding;

5, vocoder data, message key and the error correction coding after will encrypting by CPU is modulated into the data of similar voice, namely has the voice data of phonetic feature;

6, the data volume that will be modulated into similar voice by CPU turns to the PCM data;

7, by the D/A converter PCM data are transformed into analog signal;

8, through after the 2/4 line conversion, in the PSTN net, transmit;

Two, at receiving terminal:

9, the signal that will receive in the PSTN net through 2/4 line conversion after, by the A/D converter it is transformed to the PCM data;

10, by the data of CPU from the similar voice of PCM data extract;

11, by the data demodulates of CPU with similar voice, the vocoder data that obtains encrypting, error correction coding and corresponding message key;

12, obtain vocoder data and the message key of encryption by the CPU error correction;

13, utilize message key to obtain vocoder data by the CPU deciphering;

14, by vocoder to after the vocoder data decoding, obtain analogue voice signal by the D/A conversion again.

Described at transmitting terminal:

Analogue voice signal is transformed into the PCM data by the A/D converter, refers to be transformed into the PCM data with 128Kbps;

The PCM data by the vocoder compressed vocoder data that is encoded into, are referred to that compressed encoding becomes the vocoder data of tool 2400bps;

Vocoder data, message key and error correction coding after will encrypting by CPU, be modulated into the data of similar voice, refer to be modulated into the analogous terms sound data with 4800bps, and the analogous terms sound data after will modulating is quantified as the PCM data, refers to it is quantified as the PCM data with 128Kbps.

Described at receiving terminal:

The signal of receiving in the PSTN net through 2/4 line conversion after, by the A/D converter it is transformed to the PCM data, refer to be transformed into the PCM data with 128Kbps;

By the data of CPU from the similar voice of PCM data extract, refer to obtain from the PCM data of 128Kbps the data of the similar voice of 4800bps;

By the data demodulates of CPU with similar voice, refer to the data demodulates with the similar voice of 4800bps by CPU, the vocoder data that obtains encrypting, error correction coding and corresponding message key;

Utilize message key to decipher vocoder data by CPU, refer to obtain the vocoder data of 2400bps.

The invention has the advantages that:

1), the voice data (random number) after will encrypting is modulated into the method for the data of similar voice, broken through random number (voice data after the encryption) by PSTN net transmission after, receiving end can't correctly restore the technical bottleneck of voice data, cooperate error correction coding, the error code that produces in the error code that produces in modulated process and the transmission course is corrected, guaranteed the quality of encrypted voice.Secure communication has important meaning to the PSTN net in the realization of this method, fundamentally promotes the ease for use of secure communication, simultaneously the development that promotes the national defense communication cause is had positive role.

2), need not MODEM chip and peripheral circuit, need not set up the needed time of data channel by additional wait MODEM chip, it is convenient to use, and is easy to promote.

Description of drawings

Accompanying drawing 1 is this case process of transmitting block diagram

Accompanying drawing 2 is this case receiving course block diagram

Accompanying drawing 3 is this case complete machine structure and speech transmission schematic diagram

Embodiment

Describe the present invention below in conjunction with accompanying drawing:

As shown in Figure 3, used A/D converter using TLV320AIC11 in this method, used vocoder adopts AMBE2000, and used CPU adopts TMS320C5510, and complete machine software adopts the c language to realize.

The method that encrypted voice of the present invention transmits in the PSTN net, step is as follows:

One, at transmitting terminal:

1, at first with analogue voice signal process A/D conversion, converts the PCM data of 128Kbps to;

2, with the PCM data of 128Kbps, pass through the vocoder compressed vocoder data that is encoded into 2400bps;

3, encrypt described 2400bps vocoder data and increase the message transfer key by CPU;

4, by CPU 2400bps vocoder data and message key after encrypting are carried out error correction coding;

5,2400bps vocoder data, message key and the error correction coding after will encrypting by CPU is modulated into the data of the similar voice of 4800bps, namely has the voice data of phonetic feature;

6, by the data of CPU with the similar voice of 4800bps, be quantified as the PCM data of 128Kbps;

7, by the D/A converter PCM data of 128Kbps are transformed into analog signal;

8, this analog signal through 2/4 line conversion after, in PSTN net, transmit;

Two, at receiving terminal:

9, the analog signal that will receive from the PSTN net through 2/4 line conversion after, be transformed into the PCM data of 128Kbps by the A/D converter;

10, by the PCM data of CPU from 128Kbps, extract the data of the similar voice of 4800bps;

11, by the data demodulates of CPU with the similar voice of 4800bps, the 2400bps vocoder data that obtains encrypting, error correction coding and corresponding message key;

12 2400bps vocoder data and message keys by CPU error correction acquisition encryption;

13, utilize message key to obtain the vocoder data of 2400bps by the CPU deciphering;

14, by vocoder the 2400bps vocoder data that obtains is carried out uncompressed encoding, obtain the PCM data of 128Kbps, through the D/A converter these PCM data are converted to analogue voice signal again.

Claims

1. the method in the PSTN net, transmitted of an encrypted voice, step is as follows:

One, at transmitting terminal:

7, by the D/A converter PCM data of 128kbps are transformed into analog signal;

8, this analog signal through 2/4 line conversion after, in PSTN net, transmit;

Two, at receiving terminal:

12, obtain 2400bps vocoder data and the message key of encryption by the CPU error correction;