CN101059957B - An audio coding selective cryptographic method - Google Patents

Abstract

The invention discloses a sound code selective encrypt method, comprising A, first initialization, selecting encrypt safe level, finding the adjust parameters of chaotic encrypt method, B, finding the bit positions of encrypt bit serial number list and bit position list according to the frame speed and safe level, using chaotic encrypt method to encrypt, or even composed of step C that the decrypt user receives the encrypt data, to initialize and decrypt. The invention sets object data bit of sound code according to safe level, to improve real-time property, reduce system energy consumption and meet the demands of different levels.

Description

A kind of audio coding selective cryptographic method

Technical field

The present invention relates to the speech coding technology field.Especially relate to a kind of audio coding selective cryptographic method, particularly relate to the G.723.1 selective cryptographic method of voice coding.

Background technology

Along with the growth at full speed of communication service demand, in order to guarantee the transmission of communication service data, people carry out the research work of various data compression techniques energetically.And the compressed digital transmission of voice signal is the direction of people's effort always for many years.

Prior art generally adopts the low rate speech coding technology to carry out voice transfer.The low rate voice coding is under the situation that as far as possible reduces distortion, reduces code rate, so that shared bandwidth when reducing to transmit.It is compared to analog transmission, can save bandwidth, is convenient to realize and internet (Internet Protocol, fusion IP).

G.723.1 be International Telecommunications Union's (International Telecommunication Union, ITU) voice coding standard of formulating for low code check multimedia communication.This voice coding scheme is the H.324 ingredient of standard series of ITU-T, can have two kinds of code checks of 6.3kbps and 5.3kbps with other audio signal components of low-down code check compressed voice or multimedia equipment.Pumping signal during high code check (6.3kbs) be multiple-pulse maximum likelihood quantification (Multipulse Maximum Likelihood Quantization, MP-MLQ); Pumping signal during low code check (5.3kbs) be the algebraic codebook Excited Linear Prediction (Algebraic-Code-Excited Linear-Prediction, ACELP).G.723.1 the frame length 30ms of voice signal, 240 sampled values.Scrambler adopts linear prediction-synthesis analysis coding, makes perceptual weighting error signal minimum.

In cataloged procedure, once import a frame, every frame removes DC component through high-pass filtering, is divided into 4 subframes then, 60 sampled points of every subframe.With linear prediction analysis method (Linear Predictive, LP) voice signal is carried out the short-term prediction analysis, the voice signal of each subframe after with windowing calculated its linear predictive coding (Linear Predictive Coding, LPC) 10 rank filter coefficients, the LPC coefficient of these 4 subframes will be used for setting up perceptual weighting filter in short-term, and this wave filter acts on entire frame and obtains the perceptual weighting signal.The LPC filter coefficient of last subframe also will be converted into line spectrum pair, and (Line Spectrum Pairs, LSP) coefficient use prediction division vector quantizer to quantize then.

As shown in Figure 1, be coding principle figure G.723.1.Correlativity when G.723.1 utilizing short-term correlation between the voice sampling point and adjacent voice segments long, and two kinds of residual signals after relevant removed in voice encode respectively.

At first carry out voice short-time analysis coding: 1) voice signal is through synthetic 360 sampling points of back 120 points of 240 points after the high-pass filtering and previous frame, if present frame is first frame of voice signal, then 120 of the front sampling points are 0 entirely just; 2) sampling point is divided into 4 sections of mutual overlapping, each segment length 180 is with the Hamming window function weighting of multiplying each other, to reduce this effect of jeep that segmentation brings; 3), try to achieve linear predictor coefficient by calculating such as autocorrelation functions.Short-term correlation by voice signal, change in frame can be very not big for the predictive coefficient of voice signal as can be known, so only use last 10 predictive coefficients (the LPC parameter of last subframe in each frame) to come the approximate predictive coefficient that replaces this frame voice in this scrambler.

Secondly, is the LPC Parameters Transformation of each subframe line spectrum pair (LSP) parameter, with prediction division vector quantization (Predictive Split Vector Quantizer, PSVQ) transmitted behind toleranceization, the coding: line spectrum pair (LSP) residual error vector (has been removed the LSP vector of DC component when long and the difference of LSP predictive vector, be 10 n dimensional vector ns) be divided into 3 sub-vectors, dimension is respectively 3,3,4, then each sub-vector is carried out the 8bit codebook quantification, so just produced 3 8bit codebook vectors, totally 24 bit codes originally.

In order to improve the quantification perceived quality, the voice signal after the high-pass filtering need pass through resonance peak perceptual weighting filter and harmonic peak noise shaping filter, and voice signal is carried out filtering, to generate the initial target signal.The parameter of resonance peak perceptual weighting filter is made of the non-quantized LPC coefficient of each subframe; The parameter of harmonic peak noise shaping filter is estimated to obtain by per two subframes being carried out the open-loop pitch cycle.

Voice signal is weighted the harmonious noise filtering of filtering, analyze (the fundamental tone composition also is a periodic component) when also signal being made length therebetween, promptly successively carry out open-loop pitch estimation and closed loop pitch prediction, parameter coding when obtaining voice length is relevant when at last length being removed in voice.Wherein, the pitch period of even subframe (adaptive codebook) is used 7 bits of encoded, and the pitch period of strange subframe is with 2 bit differential codings.

And residual signal deducts long time contribution by object vector and obtains.Can select 6.3kbit/s or two kinds of code checks of 5.3kbit/s to the coding (fixed codebook) of residual signal.The former (MP-MLQ algorithm) utilizes in the residual signal the involutory one-tenth voice quality impacts of small-signal little, handles and stays amplitude the greater and encode so can carry out slicing to residual signal; Latter's (ACELP algorithm) substitutes residual signal with the code word of storing in the code book, with search out and residual signal between the code vector of square error minimum transmit.The difference of two kinds of algorithms is to be used for replacing the coded pulse number difference of residual signal: the used umber of pulse of algebraic codebook Excited Linear Prediction (ACELP) is slightly less than the umber of pulse of MP-MLQ.

As shown in Figure 2, be the schematic diagram of G.723.1 decoding, it at first extracts LSP code book index value from receive code stream, and the LSP parameter through LSP decodes, interpolation obtains each subframe is converted to the LPC parameter, constitutes the LPC composite filter.From receive code stream, extract pitch period, fundamental tone gain code book index and the driving pulse information of each subframe then, obtain pumping signal e (n) through fundamental tone decoding and excitation decoding respectively, it is carried out fundamental tone filtering obtain reconstructed speech through composite filter again, reconstructed speech promptly obtains the last output of demoder through resonance peak postfilter and gain adjusting unit.

By above process as can be known, the frame signal after being handled by scrambler needs transmission parameters to comprise: channel parameters, i.e. and LSP parameter is in order at decoding end structure LPC composite filter; Excitation parameters, i.e. pitch period parameter and long-term prediction gain parameter, the pulse position parameter and the gain parameter of random code book.

Traditional voice coding encryption method all is that the stream of compressed voice G.723.1 integral body is encrypted.

Yet compare with text message, the voice flow data volume is big, real-time requires high, directly it is carried out bulk encryption with conventional cryptography algorithm such as AES (Advanced Encryption Standard), 3DES (3 Data EncryptionStandard) algorithm etc., can cause tangible time delay, reduce its real-time performance.Moreover, it also can significantly increase the computational load of system, takies more resources, consumes more multipotency source.This is in many occasions, under the very overcritical situation of low energy consumption, is intolerable such as mobile communication etc.In addition, audio data stream is carried out bulk encryption, be inconvenient to satisfy the business demand of different brackets.

Summary of the invention

Problem to be solved by this invention is to provide a kind of audio coding selective cryptographic method, and it selects definite data bit that needs the voice coding of encryption by safe class.

A kind of audio coding selective cryptographic method for realizing that the present invention provides comprises the following steps:

Steps A is at first carried out initialization, selects to encrypt required safe class, determines the adjusting parameter of chaotic stream encryption method;

Step B determines the encrypted byte sequence number table selected for use and the bit of the parameter in the bit position table according to frame rate and safe class, utilizes the chaotic stream encryption method to carry out cryptographic operation.

Described audio coding selective cryptographic method can also comprise the following steps:

Step C after deciphering side receives enciphered data, at first carries out initialization, carries out decryption oprerations then.

Described steps A comprises the following steps:

Steps A 1, the user selects to encrypt required safe class;

Steps A 2 is determined the adjusting parameter of chaotic stream encryption method;

Steps A 3 is got effective binary digit of regulating the initial value in the parameter, and hand-over word nodal pattern data deposit data converted in an array as the key stream table, carries out XOR in order to the position that expressly will encrypt with audio data stream, to obtain ciphertext.

Described step B comprises the following steps:

Step B1, according to a frame speech frame of receiving two judge that it is the two-forty frame, low rate frame, still quiet frame;

Step B2 according to different frames, forwards corresponding step to and handles:

If the two-forty frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use two-forty need encrypt accordingly forward step B3 to;

If low rate frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use above low rate need encrypt accordingly forward step B3 to;

If quiet frame does not then need to encrypt, rotate back into step B1, then handle next frame;

Step B3 behind the encrypted byte sequence number table and bit position table determining according to frame rate and safe class to select for use, carries out the cryptographic operation of present frame;

Step B4, finish the cryptographic operation of present frame after, if key stream uses, utilize the adjusting parameter in the described chaotic stream encryption method that current chaos sequence value is carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then go back to step B1, then handle next frame.

Described step C comprises the following steps:

Step C1 receives controlled variable and deciphering obtains the encryption safe grade, and deciphering obtains the adjusting parameter of chaotic stream encryption method;

Step C2 gets effective binary digit of regulating parameter, is converted to byte type data, deposits data converted in byte type array as the key stream table, carries out XOR in order to the position that expressly will encrypt with audio data stream, to obtain expressly;

Step C3, the concrete decryption oprerations flow process of execution present frame;

Step C4, finish the decryption oprerations of present frame after, if key stream uses, utilize to regulate parameter current chaos sequence value carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then handle next frame.

Described chaotic stream encryption method is the chaotic stream encryption method that Logistics mapped one-dimensional nonlinear iteration method characterizes.

Described Logistics mapped one-dimensional nonlinear iteration method is improved Logistics map one-dimensional nonlinear alternative manner, and described alternative manner is shown below:

G(x)＝(β+1)(1+1/β) ^βx(1-x) ^β

Wherein, β ∈ (1,4), x ₀∈ (0,1), the initial value of x are x ₀, can obtain x by this formula iteration ₁, x ₂, x ₃... x _n....

Among the described step B, by frame rate with encrypt required safe class and determine encrypted byte sequence number table and the bit position table selected for use, for:

The susceptibility of determining the bit of parameter in the speech frame puts in order, and with this bit is divided into different classes ofly, encrypts different classes of bit and obtains different safety class.

Described voice coding is the voice coding of received pronunciation frame G.723.1.

To put in order be five classes to the susceptibility of the bit of parameter in the described speech frame, is respectively CLASS1, CLASS2, and CLASS3, CLASS4, CLASS5, its importance reduces successively.

When safe class is Level 1, encrypt the bit among the CLASS1, under the high-rate mode of received pronunciation frame G.723.1 to the 48bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 38bit bit encryption in the speech frame;

When safe class is Level 2, encrypt the bit among CLASS1 and the CLASS2, in the high-rate mode of received pronunciation frame G.723.1 to the 62bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 52bit bit encryption in the speech frame;

When safe class is Level 3, encrypt the bit among CLASS1, CLASS2 and the CLASS3, under the high-rate mode of received pronunciation frame G.723.1 to the 74bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 64bit bit encryption in the speech frame;

When safe class is Level 4, encrypt the bit among CLASS1, CLASS2, CLASS3 and the CLASS4, under the high-rate mode of received pronunciation frame G.723.1 to the 86bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 76bit bit encryption in the speech frame.

The invention has the beneficial effects as follows: audio coding selective cryptographic method of the present invention, improve the real-time of voice call on the one hand.In speech frame, carry out selective encryption,, only the high/low speed frame that carries voice messaging is encrypted, a large amount of SID frame (quiet frame) is not encrypted promptly in interframe; In frame, by the needs of safe class, the bit high to those susceptibility (promptly big to the reconstructed speech influence) encrypted.The voice medium content is carried out bulk encryption compare with traditional, this accelerates enciphering rate undoubtedly; On the other hand, can reduce system energy consumption, reduce taking resource.It is by carrying out selective encryption to speech frame, and these measures also can reduce system energy consumption when raising the efficiency, and reduces the resource quantity that takies.Cutting down the consumption of energy in the very nervous applied environment of some energy resources, carry finite energy as its mobile device in the wireless communication field, is very crucial problem.Minimizing takies resource, also can alleviate the load of network processing node.Further, it can be convenient to satisfy the business demand of different brackets.Selective encryption not only can satisfy better demand technically, and it also has actual using value in the business of many internets.Such as, the website of all kinds of audio service is provided, its phonetic material can offer the user with different Cipher Strengths, if provide free the audition to the user, can take certain Cipher Strength to voice, to carry out Fuzzy Processing.Suchlike many application, in a word, selective encryption provides feasibility and good technical support for the business demand of different brackets.

Description of drawings

Fig. 1 is the G.723.1 speech coding principles figure of received pronunciation frame of prior art;

Fig. 2 is the G.723.1 tone decoding schematic diagram of received pronunciation frame of prior art;

Fig. 3 is an audio coding selective cryptographic method process flow diagram of the present invention;

Fig. 4 is a speech coding selective encryption process synoptic diagram of the present invention;

Fig. 5 is a step S100 initialization procedure process flow diagram among Fig. 4;

Fig. 6 is that step S200 selects to determine bit among Fig. 4, carries out the cryptographic operation process flow diagram flow chart;

Fig. 7 is a step S300 decrypting process process flow diagram among Fig. 4;

Fig. 8 for one embodiment of the invention G.723.1 received pronunciation vertical frame dimension rate frame safe class be that 1: the 3rd byte begins the ciphering process synoptic diagram;

Fig. 9 is G.723.1 received pronunciation frame the 10th a byte ciphering process synoptic diagram shown in Figure 8;

Figure 10 is G.723.1 received pronunciation frame the 11st a byte ciphering process synoptic diagram shown in Figure 8;

Figure 11 is G.723.1 received pronunciation frame the 12nd a byte ciphering process synoptic diagram shown in Figure 8;

Figure 12 is G.723.1 received pronunciation frame the 14th a byte ciphering process synoptic diagram shown in Figure 8;

Figure 13 for the next frame of G.723.1 received pronunciation frame shown in Figure 8 since the 3rd byte ciphering process synoptic diagram.

Embodiment

In order to make purpose of the present invention, technical scheme and advantage clearer,, a kind of audio coding selective cryptographic method of the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.

Usually, in to voice encryption measure of effectiveness standard, comprise objective and subjective evaluation and test two aspects, but arrowband compressed voice signal for low rate, the parameter of objective evaluating such as signal to noise ratio (S/N ratio) etc., be difficult to its performance performance of real reflection, and subjectivity is evaluated and tested more closing to reality situation, so more pay attention to subjective evaluation and test usually.Several main criterion in the subjective evaluation and test promptly comprise following some:

1, voice intelligibility (semanteme)

2, the sex of voice is judged

3, plaintext attack

4, quiet/non-quiet differentiation

This just wishes to that is to say standard of reaching in the evaluation and test of the subjectivity of voice, in the embodiment of the invention, should be by encrypting, and the people can not be made after listening voice about above some effective resolution behavior again.

Need to prove, more than four standards be equivalent to the highest requirement of encryption safe intensity.The cipher round results that different safe classes obtains in the embodiment of the invention is different, be not to satisfy above four standards, and the method among the present invention is to the efficient of encrypting and a kind of compromise of security intensity, seeks an equilibrium point between the two.Above standard only is our a total standard and principle of wishing to reach, and does not have direct correlation to get in touch with safe class of the present invention or the like, also not ordering successively.

Digital speech, image and video compression data stream all have a characteristic, be the unbalanced importance (nonuniform perceptual importance) on the sense organ, that is to say that the mistake that part position upward takes place in the data stream is more significantly than the influence that the mistake that takes place is brought on other.

Up to the present, the most important applications about this conclusion is exactly unequal error protection (Unequal Error Protection, the UEP) mechanism that adopts in the transmission of wireless channel multi-medium data.

Therefore; be different from and encrypt whole multimedia stream; audio coding selective cryptographic method of the present invention; adopt a kind of selective cryptographic method; different with the way of encrypting all data in the conventional cryptography method; selective cryptographic method is only encrypted the more great bit of perception influence a part; rest parts does not then directly add transmitting of protection in channel; promptly by keeping encryption back data format information and control information constant; only encrypt real data; thereby keep encrypting the compatibility of back data stream, it is being guaranteed under the situation of required security intensity, reduces computational load; also just saved more resources; energy consumption; transmission speed is greatly improved, and better performance has also just been arranged aspect real-time, can requirement of real time.Simultaneously, selective cryptographic method can require to combine with concrete data layout, and according to the difference that level of security requires, select to encrypt different sensitive datas, thereby meet the different needs,

The embodiment of the invention illustrates audio coding selective cryptographic method of the present invention with the selective encryption of voice coding G.723.1, but the present invention is not limited to only be applicable to G.723.1 voice coding, and it goes for the voice coding of other standard equally.

As shown in Figure 3 and Figure 4, wherein, Fig. 3 audio coding selective cryptographic method process flow diagram of the present invention; Fig. 4 is an audio coding selective ciphering process synoptic diagram of the present invention; Describe a kind of audio coding selective cryptographic method of the present invention below in detail:

Step S100 at first carries out initialization, selects to encrypt required safe class, the adjusting parameter of determining to encrypt alternative manner;

As shown in Figure 5, it specifically comprises the steps:

Step S110, user select to encrypt required safe class Level;

Step S120 determines that Logistics mapped one-dimensional nonlinear iteration method characterizes the adjusting parameter x of chaotic stream encryption method ₀And β;

The user selects this two parameter x ₀And β, these two parameters promptly are equivalent to key.x ₀Value between 0～1, β is value between 1...～4, and the figure place behind the radix point is not required, and preferably, in view of the accessible figure place of computing machine, two parameters are got behind radix point and are no more than 10.The embodiment of the invention illustrates, and described two parameters are value x ₀=0.3, β=3.78.Simultaneously, need to prove, can in computing machine VC programmed environment, these two parameters be stored as the double-precision floating points type, so that choose 64 effective binary digits.

Step S130 gets the initial value x that regulates in the parameter ₀Radix point after 64 effective binary digits, be converted to 8 byte types (byte) data, deposit the array of conversion in an array as the key stream table, carry out XOR in order to the position that expressly will encrypt with audio data stream, to obtain ciphertext.

The described prior art that is converted to, it is divided into 8 groups with 64 binary digits, and 8 bits of each group just form byte type data;

Described key stream table is 8 byte type (byte) type array keyList[for data converted being deposited in a length] obtain, it carries out XOR in order to the position that expressly will encrypt with audio data stream, to obtain ciphertext.

Step S200 determines encrypted byte sequence number table and the bit position table selected for use according to frame rate (frame length) and safe class, carries out cryptographic operation.

In the voice coding encrypted process, the user will select the bit of the definite voice coding that need encrypt according to the format characteristic of concrete cryptographic object voice coding G.723.1 after selecting to encrypt required safe class Level.

As shown in Figure 6, specifically comprise the steps:

Step S210, at first according to two of the frame speech frame received, judge its be the two-forty frame (frame length 24 bytes, 6.3kbps), low rate frame (frame length 20 bytes, 5.3kbps), or SID frame (quiet frame);

Step S220 according to different frames, forwards corresponding step to and handles;

Case1: if the two-forty frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use two-forty need encrypt accordingly forward step S230 to;

Case2: if low rate frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use above low rate need encrypt accordingly forward step S230 to;

Case3: if SID frame (quiet frame) does not then need to encrypt, rotate back into step S210, then handle next frame;

Step S230 behind the encrypted byte sequence number table and bit position table determining to select for use according to frame rate (frame length) and safe class, carries out the cryptographic operation of present frame.

Step 240, finish the cryptographic operation of present frame after, if key stream uses, utilize the adjusting parameter in the described chaotic stream encryption method that current chaos sequence value is carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then go back to step 210, then handle next frame.

Further, can also comprise the following steps:

Step S300 after deciphering side receives enciphered data, at first carries out initialization, carries out decryption oprerations then.

As shown in Figure 7, specifically comprise the steps:

Step S310 receives controlled variable and deciphering obtains encryption safe grade level, and deciphering obtains the adjusting parameter x of chaotic stream encryption method ₀And β;

Step S320 gets x ₀Radix point after 64 effective binary digits, be converted to 8 byte type data, depositing data converted in a length is 8 byte type array keyList[] as the key stream table, carry out XOR in order to the position that expressly will encrypt with audio data stream, to obtain expressly;

Step S330, the concrete decryption oprerations flow process of execution present frame;

Step S340, finish the decryption oprerations of present frame after, if key stream uses, utilize to regulate parameter current chaos sequence value carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then handle next frame.

Carry out the concrete deciphering flow process of selective cryptographic method of the present invention, the cryptographic operation flow process is corresponding with carrying out, and those skilled in the art can finish decrypting process according to the described ciphering process of the specific embodiment of the invention, therefore, in embodiments of the present invention, be described in detail no longer one by one.

Describe the adjusting parameter x of determining the chaotic stream encryption method that Logistics mapped one-dimensional nonlinear iteration method characterizes among the step S120 below in detail ₀Concrete grammar process with β:

Preferably, take all factors into consideration characteristics, efficient and the security of selective encryption, adopt the chaotic stream encryption algorithm in the embodiment of the invention, xor operation is unit with the byte, but the use to chaotic key stream improves, and in conjunction with to selected characteristics that need the encryption section position of frame structure G.723.1, can suitably reuse chaotic key stream, and extremely do not influence its security performance, thereby raise the efficiency.

The advantage of stream encryption is that wrong expansion is little, real-time is high, and its secrecy depends on the randomness of the key sequence that key generator produces, and when key sequence during very near random series, its security is very high.But in traditional stream encryption method, the pseudo-random sequence generator of employing is linear congruence generator or linear feedback shift register, and their security is all relatively poor, easily is cracked.Therefore, the embodiment of the invention adopts the chaotic stream encryption method.

As a kind of enforceable mode, a kind of simple and autonomous one-dimensional discrete dynamic system that be widely studied is the Logistics mapping method, the chaotic stream encryption method that it characterizes with the one-dimensional nonlinear alternative manner, as the formula (10).

F(x _n)＝λx _n(1-x _n) (10)

Wherein, n=0,1,2 ..., x ₀With λ is to regulate parameter, works as x ₀∈ (0,1), during λ ∈ (3.5699456..., 4), the Logistics mappings work is in chaos state, promptly by starting condition x ₀Sequence { the x that under the effect of Logistics mapping method, is produced _k, k=0,1,2,3...} is non-periodic, convergent not, and very responsive to initial value and parameter.

This chaotic stream encryption method has two problems, one is the point of fixity of stream encryption method, and promptly repeatedly iteration levels off to some fixed values, and another is " stability window ", promptly assemble at the point in certain interval, the sequence of iterations that produces in the window can not provide as the necessary security of key stream.

The embodiment of the invention adopts improved Logistics map (Logistics map) one-dimensional nonlinear alternative manner to avoid prior art problems.The alternative manner of the embodiment of the invention is as the formula (11):

G(x)＝(β+1)(1+1/β) ^βx(1-x) ^β(11)

Wherein, β ∈ (1,4), x ₀∈ (0,1), the initial value of x are x ₀, can obtain x by this formula iteration ₁, x ₂, x ₃... x _n....

In theory, the sequence that formula (11) produces is non-periodic, but owing to be subjected to the restriction of machine word length, the actual chaos sequence that is obtained by Computer Simulation all is approaching objective chaos, therefore " circulation window " problem is arranged, pass through the several times iteration exactly, iterative value occurs periodically.According to the result of test, when adopting the floating-point operation of double precision, available iteration average time＞=2*10 ⁷

Describe in detail below among the step S200 by frame rate (frame length) and the required safe class Level of encryption and determine the encrypted byte sequence number table selected for use and the concrete grammar process of bit position table:

Of the present invention by frame rate (frame length) with encrypt required safe class Level and determine encrypted byte sequence number table and the bit position table selected for use in order to illustrate, G.723.1 standard frame at first is described, and according to its parameter importance of bit frame structure analysis, select the bit that to encrypt by safe class Level needs according to its parameter importance then, susceptibility promptly how to determine the bit of parameter in the speech frame puts in order, with this bit is divided into different classes ofly, encrypts different classes of bit and obtain different safety class.

As shown in table 1 is the G.723.1 Bit Allocation in Discrete frame structure after the voice coding of low rate frame 5.3kbps pattern:

Table 1 low rate frame 5.3kbps pattern is the Bit Allocation in Discrete frame structure table after the voice coding G.723.1

Parameter

Code word

First subframe

Second subframe

The 3rd subframe

The 4th subframe

Every frame amounts to

						(bit)
							The LPC index	LPC						24
The adaptive codebook time-delay	ACL0，ACL1，ACL2，ACL3	7	2	7	2	18
							The combined coding of all gains	GAIN0，GAIN1，GAIN2，GAIN3	1 2	1 2	1 2	1 2	48
Pulse position	POS0，POS1，POS2，POS3	1 2	1 2	1 2	1 2	48
							Impulse code	PSIG0，PSIG1，PSIG2，PSIG3	4	4	4	4	16

The parity flag position	GRID0，GRID1，GRID2，GRID3	1	1	1	1	4
							Amount to						158

As shown in table 2 is the G.723.1 Bit Allocation in Discrete frame structure after the voice coding of two-forty frame 6.3kbps pattern:

Table 2 two-forty frame 6.3kbps pattern is the Bit Allocation in Discrete frame structure table after the voice coding G.723.1

Parameter	Code word	First subframe	Second subframe	The 3rd subframe	The 4th subframe	Every frame amounts to (bit)
							The LPC index	LPC						24
The adaptive codebook time-delay	ACL0，ACL1，ACL2，ACL3	7	2	7	2	18
							The combined coding of all gains	GAIN0，GAIN1，GAIN2，GAIN3	12	1 2	1 2	1 2	48
Pulse position	POS0，POS1，POS2，POS3	20	1 8	2 0	1 8	73
							Impulse code	PSIG0，PSIG1，PSIG2，PSIG3	6	5	6	5	22

The parity flag position	GRID0，GRID1，GRID2，GRID3	1	1	1	1	4
							Amount to						189

By analysis to G.723.1 cataloged procedure, the contrast frame structure, can determine the effect of each parameter in the frame:

1) the LPC index is the LPC parameter, is used for the composite filter at decoding end structure LPC, and is very crucial, and the intelligibility (i.e. semanteme) of LPC coefficient and last voice has close association;

2) associating gain G AIN0, GAIN1, GAIN2, GAIN3 are the combined codings of the gain of adaptive codebook and fixed codebook, and gain parameter affects people's ear to the conversation of voice and the resolution characteristic of quiet phase;

3) ACL0, ACL1, ACL2, ACL3 represent the adaptive codebook time-delay of first, second, third and fourth subframe respectively, and they represent the long time base sound in the voice-activated, also are the recurrent pulse composition, and this composition influence people's ear the sex of voice is judged;

4) impulse code (PSIG0, PSIG1, PSIG2, PSIG3) and pulse position (POS2 POS3) represents the symbol and the position of the coded pulse of fixed codebook (the non-periodic pulse composition in the voice-activated) respectively for POS0, POS1.Fixed codebook is in the cataloged procedure to pumping signal, to approaching of the difference of target vector and long time base sound contribution, it is the residual signal of total excitation, therefore its importance is lower than adaptive codebook, on the basis that the existing effect of adaptive codebook is encrypted, but the encryption priority postpone of fixed codebook correlation parameter is considered.

Therefore, by to voice encryption measure of effectiveness standard and G.723.1 each parameter role unite consideration, clear and definite LPC parameter, unite gain and three parameters of adaptive codebook extremely important, need when selecting encryption parameter at first to consider that the encryption of fixed codebook parameters can be considered in postpone.

Simultaneously, in order to further specify bit that need to select encryption by safe class, the embodiment of the invention is in conjunction with putting in order to the error code susceptibility of frame bit among the annex C G.723.1, analyze parameter importance in the explanation coded-bit frame structure G.723.1, and need select the bit that to encrypt by safe class.

Different bits in understanding frame structure G.723.1 to the decoding end voice signal rebuild what kind of influence is arranged after, the putting in order that has provided in conjunction with decoding among the annex C G.723.1 again to the error code susceptibility of frame bit, and according to voice encryption measure of effectiveness standard etc., according to the condition of system resource, the demand of different safety class, select to encrypt different bits, and the bit that selection will be encrypted according to safe class.

G.723.1 the annex C of ITU-T issue is about the chnnel coding in the radio communication, and because the channel bit error rate of radio communication is very high, therefore propose annex C with to G.723.1 in the frame structure error code bit of responsive (it is very big to the influence of reconstructed speech promptly to make a mistake) especially being carried out the CRC check coding, strengthen its anti-wrong performance.For this reason, provided the putting in order of error code susceptibility of the bit of improvement frame structure G.723.1 (slightly different with standard frame format, that channel error code is had stronger anti-wrong performance) among the annex C.This also is one of main favourable foundation of carrying out the selective encryption reference.

G.723.1 among the annex C slightly modified frame structure G.723.1, adapting to the transmission of wireless channel, it is that a kind of decompression of original structure represents to have stronger robustness, with the opposing channel error code.

G.723.1 two-forty (6.3kbps) the transferring voice parameter frame form of the frame of voice coding after annex C canonical solution compression G.723.1 is as shown in table 3 below:

The frame of table 3G.723.1 voice coding is after decompression

Two-forty (6.3kbps) transferring voice parameter frame form shfft

Byte sequence number in the channel	Bit
			1	R_LPC_B5...R_LPC_B0，VAD，RATE
2	R_LPC_B13...R_LPC_B6
		3	R_LPC_B21...R_LPC_B14
4	ACL0_B5...ACL0_B0，R_LPC_B23，R_LPC_B22
		5	ACL2_B4...ACL2_B0，ACL1_B1，ACL1_B0，ACL0_B6
6	AGAIN0_B3...AGAIN0_B0，ACL3_B1，ACL3_B0，ACL2_B6， ACL2_B5

7	AGAIN1_B3...AGAIN1_B0，AGAIN0_B7...AGAIN0_B4
		8	AGAIN2_B3...AGAIN2_B0，AGAIN1_B7...AGAIN1_B4
9	AGAIN3_B3...AGAIN3_B0，AGAIN2_B7..AGAIN2_B4
		10	FGAIN0_B3...FGAIN0_B0，AGAIN3_B7...AGAIN3_B4
11	FGAIN2_B1，FGAIN2_B0，FGAIN1_B4...FGAIN1_B0， FGAIN0_B4

12	FGAIN3_B4...FGAIN3_B0，FGAIN2_B4...FGAIN2_B2
		13	MSBPOS_B3...MSBPOS_B0，GRID3_B0，GRID2_B0，GRID1_B0， GRID0_B0
14	MSBPOS_B11...MSBPOS_B4
		15	POS0_B6...POS0_B0，MSBPOS_B12
16	POS0_B14...POS0_B7
		17	POS1_B6...POS1_B0，POS0_B15
18	POS2_B0，POS1_B13...POS1_B7
		19	POS2_B8...POS2_B1
20	POS3_B0，POS2_B15...POS2_B9
		21	POS3_B8...POS3_B1
22	PSIG0_B2...PSIG0_B0，POS3_B13...POS3_B9
		23	PSIG1_B4...PSIG1_B0，PSIG0_B5...PSIG0_B3
24	PSIG3_B1，PSIG3_B0，PSIG2_B5...PSIG2_B0
		25	UB，UB，UB，UB，UB，PSIG3_B4...PSIG3_B2

G.723.1 low rate (5.3kbps) the transferring voice parameter frame form of the frame of voice coding after annex C canonical solution compression G.723.1 is as shown in table 4 below:

The frame of table 4G.723.1 voice coding is after decompression

Low rate (5.3kbps) transferring voice parameter frame form shfft

Byte sequence number in the channel	Bit
			1	R_LPC_B5...R_LPC_B0，VAD，RATE
2	R_LPC_B13...R_LPC_B6
		3	R_LPC_B21...R_LPC_B14
4	ACL0_B5...ACL0_B0，R_LPC_B23，R_LPC_B22
		5	ACL2_B4...ACL2_B0，ACL1_B1，ACL1_B0，ACL0_B6
6	AGAIN0_B3...AGAIN0_B0，ACL3_B1，ACL3_B0，ACL2_B6， ACL2_B5

7	AGAIN1_B3...AGAIN1_B0，AGAIN0_B7...AGAIN0_B4
		8	AGAIN2_B3...AGAIN2_B0，AGAIN1_B7...AGAIN1_B4
9	AGAIN3_B3...AGAIN3_B0，AGAIN2_B7...AGAIN2_B4
		10	FGAIN0_B3...FGAIN0_B0，AGAIN3_B7...AGAIN3_B4
11	FGAIN2_B1，FGAIN2_B0，FGAIN1_B4...FGAIN1_B0， FGAIN0_B4
		12	FGAIN3_B4...FGAIN3_B0，FGAIN2_B4...FGAIN2_B2
13	POS0_B3...POS0_B0，GRID3_B0，GRID2_B0，GRID1_B0，GRID0_B0
		14	POS0_B11...POS0_B8，POS0_B7...POS0_B4
15	POS1_B7...POS1_B4，POS1_B3...POS1_B0
		16	POS2_B3...POS2_B0，POS1_B11...POS1_B8
17	POS2_B11...POS2_B8，POS2_B7...POS2_B4
		18	POS3_B7，POS3_B4...POS3_B3...POS3_B0

19	PSIG0_B3...PSIG0_B0，POS3_B11...POS3_B8
		20	PSIG2_B3...PSIG2_B0，PSIG1_B3...PSIG1_B0
21	UB，UB，UB，UB，PSIG3_B3...PSIG3_B0

Table 5 is the subjective susceptibility sequencing table of two-forty (6.3kbps) the transmission voice frames bit after G.723.1 annex C decompresses.The ordering of clear its subjective susceptibility of the digital watch on the corresponding bits position (most important ranking is 0, and the like).

Two-forty (6.3kbps) after table 5 decompresses

The subjective susceptibility sequencing table of transmission voice frames bit

Byte sequence number in the channel	The subjective susceptibility ordering of bit number
									1	175	180	189	190	191	192	VAD	RATE
2	98	73	107	154	167	168	169	170
									3	30	17	16	31	48	55	49	71

4	6	4	0	2	11	26	10	14
									5	5	1	3	12	27	24	60	8
6	44	66	62	82	25	61	9	7
									7	45	67	63	83	78	36	50	40
8	46	68	64	84	79	37	51	41
									9	47	69	65	85	80	38	52	42
10	56	99	159	185	81	39	53	43
									11	161	187	20	57	100	160	186	19
12	22	59	102	162	188	21	58	101

13	35	54	70	72	179	178	177	176
									14	13	15	23	28	29	32	33	34
15	128	132	146	155	163	171	181	18
									16	76	86	90	94	103	108	112	116
17	129	133	147	156	164	172	182	74
									18	183	87	91	95	104	109	113	117
19	114	118	130	134	148	157	165	173
									20	184	75	77	88	92	96	105	110
21	115	119	131	135	149	158	166	174
									22	136	124	120	89	93	97	106	111
23	151	141	137	125	121	144	150	140
									24	127	123	145	152	142	138	126	122
25	UB	UB	UB	UB	UB	153	143	139

Table 6 is subjective susceptibility sequencing tables of low rate (5.3kbps) the transmission voice frames bit after G.723.1 annex C decompresses.The ordering of clear its subjective susceptibility of the digital watch on the corresponding bits position (most important ranking is 0, and the like).

Low rate (5.3kbps) after table 6 decompresses

The subjective susceptibility sequencing table of transmission voice frames bit

Channel

The subjective susceptibility ordering of bit number

In the byte sequence number
									1	152	153	158	159	160	161	VAD	RATE
2	69	64	70	91	145	140	147	146
									3	24	15	14	25	46	50	47	63
4	4	6	0	2	11	18	10	13
									5	7	1	3	12	19	16	48	8

6	42	59	55	65	17	49	9	5
									7	43	60	56	66	26	30	34	38
8	44	61	57	67	27	31	35	39
									9	45	62	58	68	28	32	36	40
10	51	87	141	154	29	33	37	41
									11	143	156	21	52	88	142	155	20
12	23	54	90	144	157	22	53	89
									13	100	128	96	104	151	150	149	148
14	132	112	116	136	108	120	124	92
									15	109	121	125	93	101	129	97	105
16	102	130	98	106	133	113	117	137
									17	134	114	118	138	110	122	126	94
18	111	123	127	95	103	131	99	107
									19	83	79	75	71	135	115	119	139
20	85	81	77	73	84	80	76	72
									21	UB	UB	UB	UB	86	82	78	74

Can see by the table that puts in order of the frame bit susceptibility after decompressing in conjunction with G.723.1 annex C, its importance to put in order with the front be consistent to G.723.1 each parameter role and the conclusion of importance substantially.

Promptly in general, the sensitivity of parameter L PC coefficient, adaptive code vector index and gain is higher, because they are very big to the influence of reconstructed speech.

The ordering of the bit susceptibility that obtains in table 5 and the table 6 is the bit susceptibility ordering in the speech frame after the decompression of G.723.1 annex C, but required for the present invention what want is the G.723.1 ordering of the bit susceptibility in the received pronunciation frame, so need obtain two kinds of transforming relationships between the speech frame, and the corresponding relation of bit, in the hope of the ordering and the classification of bit susceptibility in the received pronunciation frame G.723.1.

Describe ordering of bit susceptibility and sort the transforming relationship between these two kinds of speech frames and the corresponding relation of bit of the bit susceptibility in the received pronunciation frame G.723.1 in the speech frame after the decompression of annex C G.723.1 below in detail:

Associative list 1 to table 6 about parameter G.723.1, and the subjective susceptibility sequencing table of annex C parameter G.723.1 and speech frame bit.As can be seen, because frame structure and standard frame after annex C G.723.1 decompresses are distinguishing on the coded sequence of each parameter inside, frame bit susceptibility after the decompression puts in order and can not be directly used in G.723.1 standard frame, so need to determine the mutual transformational relation of speech coding parameters of the speech parameter of standard G.723.1 and G.723.1 annex C standard, so that G.723.1 the speech parameter of standard can be changed mutually with the speech coding parameters of G.723.1 annex C standard.

1) transformational relation of LPC parameter:

G.723.1 in the standard code, the LPC parameter is that LSP residual error vector (has been removed the LSP vector of DC component when long and the difference of LSP predictive vector, be 10 n dimensional vector ns) be divided into 3 sub-vectors, dimension is respectively 3,3,4, then each sub-vector is carried out the 8bit codebook quantification, so just produced 3 8bit codebook vectors, totally 24 bit codes originally.

G.723.1 the LPC parameter in the standard frame obtains the LPC parameter of the frame structure among G.723.1 the annex C by following rank transformation:

G.723.1 the LPC parameter in the standard frame is made of following three sub-vectors:

E0＝{LPC_B7，LPC_B6，LPC_B5，LPC_B4，LPC_B3，LPC_B2，LPC_B1，LPC_B0}

E1＝{LPC_B15，LPC_B14，LPC_B13，LPC_B12，LPC_B11，LPC_B10，LPC_B9，LPC_B8}

E2＝{LPC_B23，LPC_B22，LPC_B21，LPC_B20，LPC_B19，LPC_B18，LPC_B17，LPC_B16}

The mapping of three sub-vector through types (1) obtains three new sub-vectors again:

$e_m^R=\mathrm{ReorderTa}{b}_m\left[e_m\right]m=\mathrm{0,1,2}---\left(1\right)$

The output that obtains promptly is the LPC parameter reference that is used for the wireless channel transmission among G.723.1 the annex C.

Therefore, the frame parameter after the decompression and the corresponding relation of standard frame parameter are among the annex C G.723.1:

R_LPC_B7...R_LPC_B0 obtains (first sub-vector) by the LPC_B7...LPC_B0 mapping:

R_LPC_B15...R_LPC_B8 obtains (second sub-vector) by the LPC_B15...LPC_B8 mapping;

R_LPC_B23...R_LPC_B16 obtains (the 3rd sub-vector) by the LPC_B23...LPC_B16 mapping;

G.723.1 among the annex C in the susceptibility sequencing table of the bit of frame structure, the susceptibility of last sub-vector (R_LPC_B23...R_LPC_B16) of LPC parameter is far above preceding two, therefore in standard frame, very high to susceptibility that LPC_B23...LPC_B_16 should be arranged, and LPC_B15...LPC_B0 susceptibility is very low.

2) transformational relation of gain parameter:

G.723.1 in the standard code, 12 bits of encoded are used in the gain of uniting of each subframe, and it in fact is the association compressed encoding of two separate gain (adaptive codebook related gain and fixed codebook related gain).In annex C G.723.1, ability for enhancement frame structure anti-channel error code, it decompresses the associating gain in the normal structure, and the FGAINx_By that the gain index GAINx_By decompress(ion) of each subframe is condensed to the AGAINx_By of one 8 bit and one 5 bit is totally two gain index.

Its step is as follows:

21) the pitch period prediction of decoding and obtaining each even subframe according to formula (2)

Wherein, PIndi is the adaptive codebook index

22) obtain the gene period forecasting of each strange subframe according to formula (3) decoding

23) calculate the gain vector of the pitch period prediction of each subframe

231) when low rate, associating gain index (GIndi) comprises the information of pitch period prediction (adaptive codebook) gain vector and the information of pulse train (fixed codebook) gain index, and its calculating formula is represented suc as formula (4):

Wherein, PGIndi is a pitch period adaptive codebook related gain index, GSize=24;

232) when two-forty, if Li＞=58, gain calculating cotype (4).Otherwise it calculates suc as formula (5):

24) calculate the maximum gain (MGIndi) of the pulse of each subframe according to formula (6)

By above decompression process, the frame parameter after can obtaining decompressing among the annex C G.723.1 and the corresponding relation of standard frame parameter are:

Pitch period adaptive codebook related gain index PGIndi in the gain index AGAINx_By corresponding (5), wherein, maximum gain MGIndi in the gain index FGAINx_By corresponding (6), the associating gain index GIndi in the corresponding following formula of the gain index GAINx_By in the standard frame format.Therefore, AGAINx_By and FGAINx_By are decompressed by GAINx_By.

GAINx_By is the parameter in the standard frame G.723.1, and AGAINx_By and FGAINx_By are the parameters in the frame structure after the G.723.1 decompression among the annex C, are compressed by the GAINx_By parametric solution in the standard frame.Among the present invention according to the transformational relation between them, corresponding relation in the hope of the bit between GAINx_By and AGAINx_By, the FGAINx_By, thereby can obtain the bit susceptibility ordering of received pronunciation frame by the bit susceptibility ordering of the frame after the decompression that provides among the annex C.

Can draw by the bit sensitivity sequencing table, the susceptibility of the gain index AGAINx_By of each subframe (y＞=3) is than higher, the gain index FGAINx_B4 position susceptibility of each subframe is very high, and low four susceptibility of AGAINx_By (y＜3) and FGAINx_By are all lower.

Because being the GAINx_By in the standard frame, AGAINx_By divides exactly 24 merchant, so these bits of AGAINx_By (y＞=3) are mainly by the highest 4 decisions of GAINx_By, so correspondingly have G.723.1 in the standard frame, the highest 4 susceptibility of GAINx_By is higher than other position.

In addition, gain index FGAINx_By most significant digit situation is complicated, not only the high position of GAINx_By is influential to it, low level also can have influence on its value, but low four susceptibility of FGAINx_By are all very low, so pay the utmost attention to encryption on the whole, also be the high position of GAINx_By to the position of the high-order influential GAINx_By of AGAIN_xBy.

Therefore, the bit of standard frame G.723.1 is divided into five class CLASS1 according to susceptibility, CLASS2, CLASS3, CLASS4, CLASS5, the bit susceptibility in the CLASS1 class is the highest, CLASS2 secondly, and the like.Therefore, the encryption of minimum safe grade Level 1 is that the bit among the CLASS1 is encrypted, a high safe class Level's 2 is that the bit among CLASS1 and the CLASS2 is encrypted ..., the encryption of high safety grade Level 4 is that the preceding 4 class bits in five classes are encrypted.

Wherein, CLASS is the classification to bit, and Level is the division to safe class.

Under standard frame high-rate mode (6.3kbps) G.723.1, the ordering of the subjective susceptibility of bit is number as shown in table 7.Need to prove that especially this table does not provide the accurate ordering of each bit, but done category division roughly, be divided into five classes and represent its susceptibility from high to low according to susceptibility.

Table 7 is in G.723.1 standard frame two-forty

Under the pattern (6.3kbps), the subjective susceptibility of bit ordering number

Byte sequence number in the channel

The subjective susceptibility ordering of bit number

1

LPC_B5 (CLASS5)

LPC_B4 (CLASS5)

LPC_B3(CLASS5)

LPC_B2(CLASS5)

LPC_B1(CLASS5)

LPC_B0(CLASSS)

VADFLAG_B0

RATEFLA G_B0

2

LPC_B13 (CLASS5)

LPC_B12 (CLASS5)

LPC_B11 (CLASS5)

LPC_B10 (CLASS5)

LPC_B9 (CLASS5)

LPC_B8 (CLASS5)

LPC_B7 (CLASS5)

LPC_B6 (CLASS5)

3

LPC_B21 (CLASS1)

LPC_B20 (CLASS1)

LPC_B19 (CLASS1)

LPC_B18 (CLASS1)

LPC_B17 (CLASS2)

LPC_B16 (CLASS2)

LPC_B15 (CLASS2)

LPC_B14 (CLASS2)

4

ACL0_B5 (CLASS1)

ACL0_B4 (CLASS1)

ACL0_B3 (CLASS1)

ACL0_B2 (CLASS1)

ACL0_B1 (CLASS1)

ACL0_B0 (CLASS1)

LPC_B23 (CLASS1)

LPC_B22 (CLASS1)

5

ACL2_B4 (CLASS1)

ACL2_B3 (CLASS1)

ACL2_B2 (CLASS1)

ACL2_B1 (CLASS1)

ACL2_B0 (CLASS1)

ACL1_B1 (CLASS1)

ACL1_B0 (CLASS2)

ACL0_B6 (CLASS1)

6

GAIN0_B3 (CLASS3)

GAIN0_B2 (CLASS4)

GAIN0_B1 (CLASS4)

GAIN0_B0 (CLASS4)

ACL3_B1 (CLASS1)

ACL3_B0 (CLASS2)

ACL2_B6 (CLASS1)

ACL2_B5 (CLASS1)

7

GAIN0_B11 (CLASS1)

GAIN0_B10 (CLASS1)

GAIN0_B9 (CLASS1)

GAIN0_B8 (CLASS1)

GAIN0_B7 (CLASS2)

GAIN0_B6 (CLASS2)

GAIN0_B5 (CLASS3)

GAIN0_B4 (CLASS3)

8

GAIN1_B7 (CLASS2)

GAIN1_B6 (CLASS2)

GAIN1_B5 (CLASS3)

GAIN1_B4 (CLASS3)

GAIN1_B3 (CLASS3)

GAIN1_B2 (CLASS4)

GAIN1_B1 (CLASS4)

GAIN1_B0 (CLASS4)

9

GAIN2_B3 (CLASS3)

GAIN2_B2 (CLASS4)

GAIN2_B1 (CLASS4)

GAIN2_B0 (CLASS4)

GAIN1_B11 (CLASS1)

GAIN1_B10 (CLASS1)

GAIN1_B9 (CLASS1)

GAIN1_B8 (CLASS1)

10

GAIN2_B11 (CLASS1)

GAIN2_B10 (CLASS1)

GAIN2_B9 (CLASS1)

GAIN2_B8 (CLASS1)

GAIN2_B7 (CLASS2)

GAIN2_B6 (CLASS2)

GAIN2_B5 (CLASS3)

GAIN2_B4 (CLASS3)

11

GAIN3_B7 (CLASS2)

GAIN3_B6 (CLASS2)

GAIN3_B5 (CLASS3)

GAIN3_B4 (CLASS3)

GAIN3_B3 (CLASS3)

GAIN3_B2 (CLASS4)

GAIN3_B1 (CLASS4)

GAIN3_B0 (CLASS4)

12

GRID3_B0 (CLASS5)

GRID2_B0 (CLASS5)

GRID1_B0 (CLASS5)

GRID0_B0 (CLASS5)

GAIN3_B11 (CLASS1)

GAIN3_B10 (CLASS1)

GAIN3_B9 (CLASS1)

GAIN3_B8 (CLASS1)

13

MSBPOS_B6 (CLASS1)

MSBPOS_B5 (CLASS1)

mBPOS_B4 (CLASS1)

MSBPOS_B3 (CLASS1)

MSBPOS_ B2 (CLASS5)

MSBPOS_ B1 (CLASS5)

MSBPOS_ B0 (CLASS5)

UB (CLASS5)

14

POS0_B1 (CLASS5)

POS0_B0 (CLASS5)

MSBPOS_B12 (CLASS1)

MSBPOS_B11 (CLASS1)

MSBPOS_B10 (CLASS1)

MSBOS_B9 (CLASS1)

MSBPOS_B8 (CLASS1)

MSBPOS_B7 (CLASSS1)

15

POS0_B9 (CLASS5)

POS0_B8 (CLASS5)

POS0_B7 (CLASS5)

POS0_B6 (CLASS5)

POS0_B5 (CLASS5)

POS0_B4 (CLASS5)

POS0_B3 (CLASS5)

POS0_B2 (CLASS5)

16

POS1_B1 (CLASS5)

POS1_B0 (CLASS5)

POS0_B15 (CLASS5)

POS0_B14 (CLASS5)

POS0_B13 (CLASS5)

POS0_B12 (CLASS5)

POS0_B11 (CLASS5)

POS0_B10 (CLASS5)

17

POS1_B9 (CLASS5)

POS1_B8 (CLASS5)

POS1_B7 (CLASS5)

POS1_B6 (CLASS5)

POS1_B5 (CLASS5)

POS1_B4 (CLASS5)

POS1_B3 (CLASS5)

POS1_B2 (CLASS5)

18

POS2_B3 (CLASS5)

POS2_B2 (CLASS5)

POS2_B1 (CLASS5)

POS1_B0 (CLASS5)

POS1_B13 (CLASS5)

POS1_B12 (CLASS5)

POS1_B11 (CLASS5)

POS1_B10 (CLASS5)

19

POS2_B11 (CLASS5)

POS2_B10 (CLASS5)

POS2_B9 (CLASS5)

POS2_B8 (CLASS5)

POS2_B7 (CLASS5)

POS2_B6 (CLASS5)

POS2_B5 (CLASS5)

POS2_B4 (CLASS5)

20

POS3_B3 (CLASS5)

POS3_B2 (CLASS5)

POS3_B1 (CLASS5)

POS3_B0 (CLASS5)

POS2_B15 (CLASS5)

POS2_B14 (CLASS5)

POS2_B13 (CLASS5)

POS2_B12 (CLASS5)

21

POS3_B11

POS3_B10

POS3_B9

POS3_B8

POS3_B7

POS3_B6

POS3_B5

POS3_B4

(CLASS5)

(CLASS5)

(CLASS5)

(CLASS5)

(CLASS5)

(CLASS5)

(CLASS5)

(CLASS5)

22

PSIG0_B5 (CLASS5)

PSIG0_B4(CLASS5)

PSIG0_B3(CLASS5)

PSIG0_B2(CLASS5)

PSIG0_B1(CLASS5)

PSIG0_B0(CLASS5)

POS3_B13(CLASS5)

POS3_B12(CLASS5)

23

PSIG2_B2 (CLASS5)

PSIG2_B1(CLASS5)

PSIG2_B0(CLASS5)

PSIG1_B4(CLASS5)

PSIG1_B3(CLASS5)

PSIG1_B2(CLASS5)

PSIG1_B1(CLASS5)

PSIG1_B0(CLASS5)

24

PSIG3_B4 (CLASS5)

PSIG3_B3(CLASS5)

PSIG3_B2(CLASS5)

PSIG3_B1(CLASS5)

PSIG3_B0(CLASS5)

PSIG2_B5(CLASS5)

PSIG2_B4(CLASS5)

PSIG2_B3(CLASS5)

Under standard frame low rate mode (5.3kbps) G.723.1, the ordering of the subjective susceptibility of bit is number as shown in table 8:

Table 8 is in G.723.1 standard frame low rate

Under the pattern (5.3kbps), the subjective susceptibility of bit ordering number

Byte sequence number in the channel

The subjective susceptibility ordering of bit number

1

LPC_B5(CLASS5)

LPC_B4(CLASS5)

LPC_B3(CLASS5)

LPC_B2(CLASS5)

LPC_B1(CLASS5)

LPC_B0(CLASS5)

VADFLAG_B0

RATEFLAG_B0

2

LPC_B13(CLASS5)

LPC_B12(CLASS5)

LPC_B11(CLASS5)

LPC_B10(CLASS5)

LPC_B9(CLASS5)

LPC_B8(CLASS5)

LPC_B7(CLASS5)

LPC_B6(CLASS5)

3

LPC_B21(CLASS1)

LPC_B20(CLASS1)

LPC_B19(CLASS1)

LPC_B18(CLASS1)

LPC_B17(CLASS2)

LPC_B16(CLASS2)

LPC_B15(CLASS2)

LPC_B14(CLASS2)

4

ACL0_B5(CLASS1)

ACL0_B4(CLASS1)

ACL0_B3(CLASS1)

ACL0_B2(CLASS1)

ACL0_B1(CLASS1)

ACL0_B0(CLASS1)

LPC_B23(CLASS1)

LPC_B22(CLASS1)

5

ACL2_B4(CLASS1)

ACL2_B3(CLASS1)

ACL2_B2(CLASS1)

ACL2_B1(CLASS1)

ACL2_B0(CLASS1)

ACL1_B1(CLASS1)

ACL1_B0(CLASS2)

ACL0_B6(CLASS1)

6

GAIN0_B3(CLASS3)

GAIN0_B2(CLASS4)

GAIN0_B1(CLASS4)

GAIN0_B0(CLASS4)

ACL3_B1(CLASS1)

ACL3_B0(CLASS2)

ACL2_B6(CLASS1)

ACL2_B5(CLASS1)

7

GAIN0_B1 1 (CLASS1)

GAIN0_B10 (CLASS1)

GAIN0_B9 (CLASS1)

GAIN0_B8 (CLASS1)

GAIN0_B7 (CLASS2)

GAIN0_B6 (CLASS2)

GAIN0_B5 (CLASS3)

GAIN0_B4 (CLASS3)

8

GAIN1_B 7 (CLASS2)

GAIN1_B6 (CLASS2)

GAIN1_B5 (CLASS3)

GAIN1_B4 (CLASS3)

GAIN1_B3 (CLASS3)

GAIN1_B2 (CLASS4)

GAIN1_B1 (CLASS4)

GAIN1_B0 (CLASS4)

9

GAIN2_B3 (CLASS3)

GAIN2_B2 (CLASS4)

GAIN2_B1 (CLASS4)

GAIN2_B0 (CLASS4)

GAIN1_B11 (CLASS1)

GAIN1_B10 (CLASS1)

GAIN1_B9 (CLASS1)

GAIN1_B8 (CLASS1)

10

GAIN2_B1 1 (CLASS1)

GAIN2_B10 (CLASS1)

GAIN2_B9 (CLASS1)

GAIN2_B8 (CLASS1)

GAIN2_B7 (CLASS2)

GAIN2_B6 (CLASS2)

GAIN2_B5 (CLASS3)

GAIN2_B4 (CLASS3)

11

GAIN3_B 7 (CLASS2)

GAIN3_B6 (CLASS2)

GAIN3_B5 (CLASS3)

GAIN3_B4 (CLASS3)

GAIN3_B3 (CLASS3)

GAIN3_B2 (CLASS4)

GAIN3_B1 (CLASS4)

GAIN3_B0 (CLASS4)

12

GRID3_B 0 (CLASS5)

GRID2_B0 (CLASS5)

GRID1_B 0 (CLASS5)

GRID0_B 0 (CLASS5)

GAIN3_B11 (CLASS1)

GAIN3_B10 (CLASS1)

GAIN3_B9 (CLASS1)

GAIN3_B8 (CLASS1)

13

POS0_B7 (CLASS5)

POS0_B6 (CLASS5)

POS0_B5 (CLASS5)

POS0_B4 (CLASS5)

POS0_B3 (CLASS5)

POS0_B2 (CLASS5)

POS0_B1 (CLASS5)

POS0_B0 (CLASS5)

14

POS1_B3 (CLASS5)

POS1_B2 (CLASS5)

POS1_B1 (CLASS5)

POS1_B0 (CLASS5)

POS0_B11 (CLASS5)

POS0_B10 (CLASS5)

POS0_B9 (CLASS5)

POS0_B8 (CLASS5)

15

POS1_B1 1 (CLASS5)

POS1_B10 (CLASS5)

POS1_B9 (CLASS5)

POS1_B8 (CLASS5)

POS1_B7 (CLASS5)

POS1_B6 (CLASS5)

POS1_B5 (CLASS5)

POS1_B4 (CLASS5)

16

POS2_B7 (CLASS5)

POS2_B6 (CLASS5)

POS2_B5 (CLASS5)

POS2_B4 (CLASS5)

POS2_B3 (CLASS5)

POS2_B2 (CLASS5)

POS2_B1 (CLASS5)

POS2_B0 (CLASS5)

17

POS3_B3 (CLASS5)

POS3_B2 (CLASS5)

POS3_B1 (CLASS5)

POS3_B0 (CLASS5)

POS2_B11 (CLASS5)

POS2_B10 (CLASS5)

POS2_B9 (CLASS5)

POS2_B8 (CLASS5)

18

POS3_B1 1 (CLASS5)

POS3_B10 (CLASS5)

POS3_B9 (CLASS5)

POS3_B8 (CLASS5)

POS3_B7 (CLASS5)

POS3_B6 (CLASS5)

POS3_B5 (CLASS5)

POS3_B4 (CLASS5)

19

PSIG1_B3 (CLASS5)

PSIG1_B2 (CLASS5)

PSIG1_B1 (CLASS5)

PSIG1_B0 (CLASS5)

PSIG0_B3 (CLASS5)

PSIG0_B2 (CLASS5)

PSIG0_B1 (CLASS5)

PSIG0_B0 (CLASS5)

20

PSIG3_B3 (CLASS5)

PSIG3_B2 (CLASS5)

PSIG3_B1 (CLASS5)

PSIG3_B0 (CLASS5)

PSIG2_B3 (CLASS5)

PSIG2_B2 (CLASS5)

PSIG2_B1 (CLASS5)

PSIG2_B0 (CLASS5)

Can obtain from table 7 and table 8, when safe class is Level 1, encrypt the bit among the CLASS1, be total to 48 that need to encrypt among the CLASS1 down in high-rate mode (6.3kbps), therefore to the 48bit bit encryption in the speech frame; Be total to 38 that need to encrypt among the CLASS1 down in low rate mode (5.3kbps), therefore to the 38bit bit encryption in the speech frame;

When safe class is Level 2, encrypt the bit among CLASS1 and the CLASS2, under high-rate mode (6.3kbps), also need to encrypt 14 among the CLASS2, therefore to the 48+14=62bit bit encryption in the speech frame; Also need to encrypt 14 among the CLASS2 under the low rate mode (5.3kbps), therefore to the 38+12=52bit bit encryption in the speech frame;

When safe class is Level 3, encrypt the bit among CLASS1, CLASS2 and the CLASS3, under high-rate mode (6.3kbps), also need to encrypt 12 among the CLASS3, therefore to the 62+12=74bit bit encryption in the speech frame; Under low rate mode (5.3kbps), also need to encrypt 12 among the CLASS3, therefore to the 52+12=64bit bit encryption in the speech frame;

When safe class is Level 4, encrypt the bit among CLASS1, CLASS2, CLASS3 and the CLASS4, under high-rate mode (6.3kbps), also need to encrypt 12 among the CLASS4, therefore to the 74+12=86bit bit encryption in the speech frame; Under low rate mode (5.3kbps), also need to encrypt 12, therefore to the 64+12=76bit bit encryption in the speech frame.

In embodiments of the present invention, susceptibility ordering according to bit, give 48 bits (bit) for the first kind (CLASS1), second class is given 14 bits (bit) ..., it is a preferable division category, the most responsive 48 divide the first kind into, are because it has included the most important bit part of several important parameters.

In embodiments of the present invention, provided the priority of the encryption of bit, without limits certain concrete application background and security intensity demand.If in certain practical application, bit is carried out the application requirements that encryption safe intensity does not reach concrete environment, increase encryption on this basis successively, up to obtaining required effect to the bit among CLASS1, the CLASS2....Those of ordinary skill in the art can bit is carried out the susceptibility ordering, but it not exceed scope of the present invention according to this area division methods commonly used yet.

As a kind of enforceable mode, the data structure of the bit position table that each byte need be encrypted in described safe class and selective encryption one frame can be expressed as follows:

/ * safe class */

#define SECURITY_LEVEL1 1 // needs are encrypted the bit among the CLASS1 set forth above

#define SECURITY_LEVEL2 2 // needs are encrypted the bit in CLASS1 set forth above～2

#define SECURITY_LEVEL3 3 // needs are encrypted the bit in CLASS1 set forth above～3

#define SECURITY_LEVEL4 4 // needs are encrypted the bit in CLASS1 set forth above～4

The byte sequence number table * that need encrypt in/* selective encryption one frame/

byte highrate_bytepos_list[]＝{3，4，5，6，7，8，9，10，11，12，13，14}；

byte lowrate_bytepos_list[]＝{3，4，5，6，7，8，9，10，11，12}；

The bit position table * that each byte need be encrypted in/* selective encryption one frame/

byte highrate_level 1_bitpos_list[]＝{0xf0，0xff，0xfd，0x0b，0xf0，0x00，

0x0f，0xf0，0x00，0x0f，0xf0，0x3f}；

When // two-forty, safe class grade 1, the bit position table of selecting for use

byte highrate_level 2_bitpos_list[]＝{0xff，0xff，0xff，0x0f，0xfc，0xc0，

0x0f，0xfc，0xc0，0x0f，0xf0，0x3f}；

When // two-forty, safe class grade 2, the bit position table of selecting for use

byte highrate_level 3_bitpos_list[]＝{0xff，0xff，0xff，0x8f，0xff，0xf8，

0x8f，0xff，0xf8，0x0f，0xf0，0x3f}；

When // two-forty, safe class grade 3, the bit position table of selecting for use

byte highrate_level 4_bitpos_list[]＝{0xff，0xff，0xff，0xff，0xff，0xff，

0xff，0xff，0xff，0x0f，0xf0，0x3f}；

When // two-forty, safe class class 4, the bit position table of selecting for use

byte lowrate_level 1_bitpos_list[]＝{0xf0，0xff，0xfd，0x0b，0xf0，0x00，

0x0f，0xf0，0x00，0x0f}；

When // low rate, safe class grade 1, the bit position table of selecting for use

byte lowrate_level 2_bitpos_list[]＝{0xff，0xff，0xff，0x0f，0xfc，0xc0，

0x0f，0xfc，，0xc0，0x0f}；

When // low rate, safe class grade 2, the bit position table of selecting for use

byte lowrate_level 3_bitpos_list[]＝{0xff，0xff，0xff，0x8f，0xff，0xf8，

0x8f，0xff，0xf8，0x0f}；

When // low rate, safe class grade 3, the bit position table of selecting for use

byte lowrate_level 4_bitpos_list[]＝{0xff，0xff，0xff，0xff，0xff，0xff，

0xff，0xff，0xff，0x0f}；

When // low rate, safe class class 4, the bit position table of selecting for use

Describe the concrete grammar process that step S230 of the present invention carries out cryptographic operation below in detail:

At first, frame sign G.723.1 has three kinds: 24 bytes (6.4kbit/s frame), and 20 bytes (5.3kbit/s frame) and 4 bytes, wherein 4 byte frames are SID (quiet insertion deictic word), how at interval without limits three kinds of frames.The size of its frame is by two the bit VADFLAG_B0 and the RATEFLAG_B0 reflection of every frame.Its corresponding relation is as shown in table 9:

The mapping table of table 9VADFLAG_B0 and RATEFLAG_B0 and every frame bit number

RATEFLAG_B0	VADFLAG	Every frame bit number (bit)
			0	0	192 (24 bytes)
0	1	160 (20 bytes)
			1	0	32 (4 bytes)
Acquiescence	Acquiescence	8 (1 bytes)

Therefore, as can be seen, two of VADFLAG_B0 and RATEFLAG_B0 are used for distinguishing G.723.1 three kinds of frames, can not encrypt.

According to this frame structure characteristics, it is necessary keeping every frame frame head VADFLAG_B0 and RATEFLAG_B0, judges whether to belong to quiet frame with this.

Simultaneously, in coding G.723.1,, be invalid data volume and quiet frame comprises because the valid data of voice are included in the speech frame of every frame 24 bytes and 20 bytes, so when encrypting, just need not encrypt, can reduce the ciphered data amount like this to quiet frame.

In embodiments of the present invention, as shown in Figure 8; With two-forty speech frame, safe class is that 1 situation is that example is analyzed explanation, and the byte sequence number table that will encrypt this moment is selected byte highrate_bytepos_list[for use], bit position table is selected byte highrate_level 1_bitpos_list[for use].

Wherein, in the two-forty speech frame 71 (frame 24 bytes), italic band underscore is represented the position that this byte has needs to encrypt, otherwise does not have.

Array 72 expression length are 12 byte (byte) type array, and its first data of depositing are corresponding to the 3rd frame of speech frame, and preceding four is that preceding four needs of 1 expression speech frame the 3rd frame are encrypted, and back four then do not need, and the rest may be inferred.

Array keyList[8] get 64 binary digits behind the 73 table Table X i radix point, generate byte type (byte) the type data of 8 bytes, deposit array keyList[8 in] in 73.

Specifically comprise the steps:

Step S231 at first receives first frame of speech frame, is assumed to be the two-forty frame herein after judging, safe class is 1, searches array byte highrate_bytepos_list[] the 1st be 3, illustrate that the 3rd byte of speech frame has the position that will encrypt;

Step S232, array byte highrate_level 1_bitpos_list[] the bit that need encrypt of the 3rd byte of the 1st record speech frame, take out its value 11110000, bit is that the bit of the corresponding speech frame byte of 1 explanation needs to encrypt, otherwise need not;

Step S233, with 11110000 with array keyList[] (depositing 64 key streams of generation) the 1st with, the 3rd byte of result who obtains and speech frame is carried out XOR, the result sends speech frame the 3rd byte back to;

Step S234 searches array byte highrate_bytepos_list[again] the 2nd be 4, illustrate that the 4th byte of speech frame has the position that will encrypt;

Step S235, array byte highrate_level 1_bitpos_list[] the bit that need encrypt of the 4th byte of the 2nd record speech frame, take out its value 11111111;

Step S236 is with array keyList[] the 2nd with, the 4th byte of result who obtains and speech frame is carried out XOR, the result sends speech frame the 4th byte back to.

By that analogy, up to being encrypted, the 10th byte of speech frame finishes, as shown in Figure 9.

Step S237, when the 11st byte of speech frame need be encrypted, keyList[] show to get back to the 1st of gauge outfit, carry out XOR with this byte and speech frame the 11st byte and encrypt.

As shown in figure 10, when proceeding to step S237, keyList[] the 8th byte also use up when the 11st byte of speech frame need be encrypted, keyList[] table gets back to the 1st of gauge outfit, carries out the XOR encryption with this byte and speech frame the 11st byte.Because the bit that each byte of speech frame will be encrypted is also inequality, even keyList[] to reuse, the bit that wherein really uses each time also is not quite similar.

Step S238 slides backward and continues to encrypt the 12nd byte, simultaneously, and keyList[] show also to slide rearwardly to the 2nd, byte highrate_bytepos_list[] and byte highrate_level 1_bitpos_list[] also move one backward;

As shown in figure 11, after speech frame the 11st byte has been encrypted, slide backward and continue to encrypt the 12nd byte, simultaneously, keyList[] show also to slide rearwardly to the 2nd, byte highrate_bytepos_list[] and byte highrate_level 1_bitpos_list[] also move one backward;

By that analogy, finish speech frame the 14th byte to encrypting, this speech frame is encrypted and is finished, because the 14th byte does not need the byte of encrypting later on, as shown in figure 12.

Step S239 after the encryption of current speech frame is finished, gets the next frame speech frame, judges whether to be quiet frame, if quiet frame is not then carried out cryptographic operation, continues to get next frame; If not quiet frame, then continue next step;

At this moment, as shown in figure 13, keyList[] show to bring into use from the 2nd, carry out xor operation with the byte (being byte 3) that the 1st needs of speech frame are encrypted.

Subsequent operation is the same with the previous frame speech frame, speech frame byte, keyList[], byte highrate_bytepos_list[] and byte highrate_level 1_bitpos_list[] all correspondingly move backward, the byte-by-byte XOR that carries out is encrypted.Up to keyList[] the 8th use, get back to the 1st of its gauge outfit, continue again and next byte XOR of speech frame is encrypted, finish up to this speech frame encryption.

Take off a non-quiet speech frame again, keyList[] show to bring into use from the 3rd, encrypt with the byte-by-byte XOR that carries out of last class Sihe speech frame, encrypt up to this frame and finish.

Take off a non-quiet speech frame again, keyList[] show to bring into use from the 8th, encrypt with the byte-by-byte XOR that carries out of last class Sihe speech frame, encrypt up to this frame and finish.

At this moment, encrypted 8 non-quiet frames, keyList[] the table calcellation, need to upgrade.Utilize formula (9)

G(x)＝(β+1)(1+1/β) ^βx(1-x) ^β， (9)

To x _i(currency of x) carries out iteration, obtains x _I+1, get x _I+1Radix point after 64 effective binary digits, be converted to 8 byte type data, deposit data converted in array keyList[], realized keyList[] renewal.

Continue to get the non-quiet frame of a frame, keyList[] show to bring into use from the 1st;

Continue to get the non-quiet frame of a frame, keyList[] show to bring into use from the 2nd;

Continue to get the non-quiet frame of a frame, keyList[] show to bring into use from the 3rd;

Repeat said process, get the non-quiet frame of a frame, keyList[until the 8th time] show to bring into use from the 8th.

Like this, encrypt and finish 8 non-quiet frames, to x _iCarry out iteration, obtain x _I+1To keyList[] upgrade.Handle next 8 non-quiet frames with this.

Finish up to all speech frames encryptions.

Audio coding selective cryptographic method of the present invention uses selective encryption that encoded voice is G.723.1 carried out chaotic stream encryption, has following advantage:

1) real-time of raising voice call

Audio coding selective cryptographic method improves encryption efficiency from following several respects:

A1) speech frame is carried out selective encryption,, only the high/low speed frame that carries voice messaging is encrypted, a large amount of SID frame (quiet frame) is not encrypted in interframe; In frame, by the needs of safe class, the bit high to those susceptibility (promptly big to the reconstructed speech influence) encrypted.The voice medium content is carried out bulk encryption compare with traditional, this accelerates enciphering rate undoubtedly.

A2) use stream cipher algorithm is incited somebody to action expressly direct and key stream carries out XOR, compares grouping algorithm, and this method speed is faster.

A3) in order to strengthen security, the key stream that uses in the stream cipher algorithm is chaos sequence, is obtained by improved Logistics map mapping.This method is in iterative process, computation complexity is bigger, in order to reduce the calculated amount of key stream, in conjunction with selected characteristics that need the encryption section position of frame structure G.723.1, suitably chaotic key stream is reused (specifically seeing the example detailed annotation), and its security performance of not appreciable impact.

2) reduce system energy consumption, reduce taking resource

Speech frame is carried out selective encryption, use stream cipher algorithm, chaotic key stream is carried out suitable recycling, these measures also can reduce system energy consumption when raising the efficiency, and reduce the resource quantity that takies.Cutting down the consumption of energy in the very nervous applied environment of some energy resources, carry finite energy as its mobile device in the wireless communication field, is very crucial problem.Minimizing takies resource, also can alleviate the load of network processing node.

3) be convenient to satisfy the business demand of different brackets

Selective encryption not only can satisfy better demand technically, and it also has actual using value in the business of many internets.Such as, the website of all kinds of audio service is provided, its phonetic material can offer the user with different Cipher Strengths, if provide free the audition to the user, can take certain Cipher Strength to voice, to carry out Fuzzy Processing.Suchlike many application, in a word, selective encryption provides feasibility and good technical support for the business demand of different brackets.

More than specific embodiments of the invention are described and illustrate it is exemplary that these embodiment should be considered to it, and be not used in and limit the invention, the present invention should make an explanation according to appended claim.

Claims (10)

1. an audio coding selective cryptographic method is characterized in that, comprises the following steps:

Steps A is at first carried out initialization, selects to encrypt required safe class, determines the adjusting parameter of chaotic stream encryption method;

Step B determines the encrypted byte sequence number table selected for use and the bit of the parameter in the bit position table according to frame rate and safe class, utilizes the chaotic stream encryption method to carry out cryptographic operation;

Described step B comprises the following steps:

Step B1, according to a frame speech frame of receiving two judge that it is the two-forty frame, low rate frame, still quiet frame;

Step B2 according to different frames, forwards corresponding step to and handles:

If the two-forty frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use two-forty need encrypt accordingly forward step B3 to;

If low rate frame, byte sequence number table and the pairing bit position table of required safe class of then selecting for use low rate need encrypt accordingly forward step B3 to;

If quiet frame does not then need to encrypt, rotate back into step B1, then handle next frame;

Step B3 behind the encrypted byte sequence number table and bit position table determining according to frame rate and safe class to select for use, carries out the cryptographic operation of present frame;

Step B4, finish the cryptographic operation of present frame after, if key stream uses, utilize the adjusting parameter in the described chaotic stream encryption method that current chaos sequence value is carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then go back to step B1, then handle next frame.

2. audio coding selective cryptographic method according to claim 1 is characterized in that, also comprises the following steps:

Step C after deciphering side receives enciphered data, at first carries out initialization, carries out decryption oprerations then.

3. audio coding selective cryptographic method according to claim 1 and 2 is characterized in that described steps A comprises the following steps:

Steps A 1, the user selects to encrypt required safe class;

Steps A 2 is determined the adjusting parameter of chaotic stream encryption method;

Steps A 3 is got effective binary digit of regulating the initial value in the parameter, and hand-over word nodal pattern data deposit data converted in an array as the key stream table, carries out XOR in order to the position that expressly will encrypt with audio data stream, to obtain ciphertext.

4. audio coding selective cryptographic method according to claim 2 is characterized in that described step C comprises the following steps:

Step C1 receives controlled variable and deciphering obtains the encryption safe grade, and deciphering obtains the adjusting parameter of chaotic stream encryption method;

Step C2 gets effective binary digit of regulating parameter, is converted to byte type data, deposits data converted in byte type array as the key stream table, carries out XOR in order to the position that expressly will encrypt with audio data stream, to obtain expressly;

Step C3, the decryption oprerations flow process of execution present frame;

Step C4, finish the decryption oprerations of present frame after, if key stream uses, utilize to regulate parameter current chaos sequence value carried out iteration, obtain new key stream, upgrade the key stream table; If also have speech frame, then handle next frame.

5. audio coding selective cryptographic method according to claim 1 and 2 is characterized in that, described chaotic stream encryption method is the chaotic stream encryption method that Logistics mapped one-dimensional nonlinear iteration method characterizes.

6. audio coding selective cryptographic method according to claim 5 is characterized in that, described Logistics mapped one-dimensional nonlinear iteration method is improved Logistics map one-dimensional nonlinear alternative manner, and described alternative manner is shown below:

G(x)＝(β+1)(1+1/β) ^βx(1-x) ^β

Wherein, β ∈ (1,4), x ₀∈ (0,1), the initial value of x are x ₀, can obtain x by this formula iteration ₁, x ₂, x ₃... x _n....

7. audio coding selective cryptographic method according to claim 1 and 2 is characterized in that, among the described step B, and by frame rate with encrypt required safe class and determine encrypted byte sequence number table and the bit position table selected for use, for:

The susceptibility of determining the bit of parameter in the speech frame puts in order, and with this bit is divided into different classes ofly, encrypts different classes of bit and obtains different safety class.

8. audio coding selective cryptographic method according to claim 7 is characterized in that, described voice coding is the voice coding of received pronunciation frame G.723.1.

9. audio coding selective cryptographic method according to claim 8 is characterized in that, to put in order be five classes to the susceptibility of the bit of parameter in the described speech frame, be respectively CLASS1, CLASS2, CLASS3, CLASS4, CLASS5, its importance reduces successively.

10. audio coding selective cryptographic method according to claim 9 is characterized in that,

When safe class is Level 1, encrypt the bit among the CLASS1, under the high-rate mode of received pronunciation frame G.723.1 to the 48bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 38bit bit encryption in the speech frame;

When safe class is Level 2, encrypt the bit among CLASS1 and the CLASS2, in the high-rate mode of received pronunciation frame G.723.1 to the 62bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 52bit bit encryption in the speech frame;

When safe class is Leve1 3, encrypt the bit among CLASS1, CLASS2 and the CLASS3, under the high-rate mode of received pronunciation frame G.723.1 to the 74bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 64bit bit encryption in the speech frame;

When safe class is Level 4, encrypt the bit among CLASS1, CLASS2, CLASS3 and the CLASS4, under the high-rate mode of received pronunciation frame G.723.1 to the 86bit bit encryption in the speech frame; Under the low rate mode of received pronunciation frame G.723.1 to the 76bit bit encryption in the speech frame.

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