End-to-end speech encryption method for low-speed narrowband wireless digital communication

Abstract

The invention provides an end-to-end speech encryption method for a low-speed narrowband wireless digital communication system; the main idea of the method is that synchronous control information during the process of one call is divided into two parts one of which is not changed during the whole call process and the other one of which is changed constantly along with a speech frame, wherein the unchanged part is sent by a control signalling and the changed part is sent together along with speech data. Therefore, the synchronous control information required to be frequently sent is effectively decreased. A synchronous mechanism of the invention has the advantages that (1) a problem on speech interruption is avoided so as to guarantee the coherent speech, (2) as a legitimacy validation is not required to be frequently carried out on the synchronous control information during the call, the synchronous efficiency is effectively improved, (3) the situation of failing to decrypt a plurality of continuous speech frames is avoided, and (4) a problem resulted from the limited bearing capacity of the low-speed narrowband wireless digital communication system is solved.

Description

technical field [0001] The invention belongs to the communication field, and relates to an end-to-end voice encryption method for a low-speed narrowband wireless digital communication system, which can be applied to digital mobile communication systems of various systems. Background technique [0002] The main idea of ​​end-to-end voice encryption is: the voice is encrypted at the sending end and decrypted at the receiving end, so as to ensure that the voice does not exist in plain text in the device node between the calling party and the called party. [0003] The stream cipher algorithm is very suitable for end-to-end voice encryption with high real-time requirements due to its advantages of no error diffusion and pre-computation. During the use of the stream cipher algorithm, both the calling party and the called party must be synchronized to implement encryption and decryption correctly, that is, both the calling party and the called party use the same key stream to encr...

AI Technical Summary

Problems solved by technology

[0009] Obviously, the DMR system cannot directly apply the end-to-end voice encryption synchronization mechanism in the TETRA standard

There are two reasons: (1) The communication rate of the DMR system is lower than that of the TETRA system, a CSBK signaling can only carry 80bits of information, and even a 30ms time slot cannot carry the 119bits synchronization control information in the TETRA system; (2) Misappropriating a 30ms time slot in the DMR system means that the voice is interrupted for 60ms, while in TETRA it is only interrupted for 30ms, which will significantly reduce the voice quality and affect the user experience

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