阅读说明：本技术 一种用于虹膜特征保护的双重加密算法 (A kind of double-encryption algorithm for iris feature protection ) 是由 张恒 焦文明 张键 李宏然 臧奇颜 陈烽 孙雪娇 徐伟伟 许腾腾 潘家乐 于 2019-08-14 设计创作，主要内容包括：本发明公开了一种用于虹膜特征保护的双重加密算法,其实现的具体步骤为：利用混沌函数构建用于虹膜区域特征映射的混沌密钥序列；第一重扩散加密算法；第二重扩散加密算法；参数值导入逆向解密虹膜区域。本发明的算法充分考虑了虹膜区域的信息量大和冗余度高的特色,采用混沌系统对虹膜区域特征进行映射；同时使用双重扩散系统对混沌密钥序列进行双重加密,极大的增强了虹膜特征信息在网络传输中的时效性和安全性,保护了个人隐私和信息安全,特别适用于现代化生物学特征在生产、生活、商业和高端机密等场所的应用。(The invention discloses a kind of double-encryption algorithm for iris feature protection, the specific steps realized are as follows: the chaotic key sequence of iris region Feature Mapping is used for using chaotic function building；First re-diffusion Encryption Algorithm；Second re-diffusion Encryption Algorithm；Parameter value imports reverse decryption iris region.Algorithm of the invention has fully considered the characteristic high with redundancy that contain much information of iris region, is mapped using chaos system iris region feature；Double-encryption is carried out to chaotic key sequence using dual diffusion system simultaneously; greatly enhance timeliness and safety of the iris feature information in network transmission; individual privacy and information security are protected, the application especially suitable for modernization biological property in places such as production, life, business and high-end secrets.)

1. a kind of double-encryption algorithm for iris feature protection, which comprises the following steps:

Step (1): the chaotic key sequence of iris region Feature Mapping is used for using chaotic function building；

Step (2): the first re-diffusion Encryption Algorithm；

Step (3): the second re-diffusion Encryption Algorithm；

Step (4): parameter value imports reverse decryption iris region.

2. a kind of double-encryption algorithm for iris feature protection according to claim 1, it is characterised in that: the step Suddenly the chaotic function feature using chaotic function building for the chaotic key sequence of iris region Feature Mapping in (1) are as follows:

Feature (1a): sensitive to primary condition；

Feature (1b): must be Topologically mixing structure；

Feature (1c): at least one intensive periodic orbit.

3. a kind of double-encryption algorithm for iris feature protection according to claim 1, it is characterised in that: the step Suddenly the main algorithm step of the spread spectrum encryption in (2) and the step (3) is divided into:

Step (2a): scramble information is carried out to plaintext by common scrambling algorithm；

Step (2b): calculating is diffused to image pixel by common broadcast algorithm.

4. a kind of double-encryption algorithm for iris feature protection according to claim 1, it is characterised in that: the step Suddenly the spread spectrum encrypted feature in (2) and the step (3) are as follows:

Assuming that the pixel sequence for the original plaintext image to be encrypted by P (k) | k=1,2 ..., m } indicate；Chaotic key sequence It is indicated by W；Step (2) diffusion encryption after obtain ciphertext image pixel sequence by Q (k) | k=1,2 ..., m } It indicates；Step (3) diffusion encryption after obtain final ciphertext image pixel sequence by R (k) | k=1,2 ..., m } It indicates:

Feature (3a): in the diffusion ciphering process of step (3), do not join directly between final ciphertext R (k) and original plaintext P (k) System；

Feature (3b): W (k) can not be inverted using the encryption formula of step (3)；

Feature (3c): in each ciphering process, there are XOR operations and non-linear " mould " operation between ciphertext and plaintext.

5. a kind of double-encryption algorithm for iris feature protection according to claim 1, it is characterised in that: the step Suddenly the reverse decryption iris region algorithm characteristics in (4) are as follows:

Feature (4a): input decipherment algorithm main contents are chaotic key sequence, encryption parameter value and final key；

Feature (4b): initial key is identical with all parameter values during encryption and decryption processes；

Feature (4c): final decrypted image is identical with encrypted image.

6. the main algorithm step of diffusion encryption according to claim 3, which is characterized in that adding in the step (2a) Algorithm is disturbed to be divided into:

(2a1): Arnold conversion scrambling: the image for being N × N for size, the home position [x of pixel₀,y₀] by can New location of pixels [the x that inverse two-dimensional matrix obtains₁,y₁]；

(2a2): Baker transformation scrambling: image is mapped by horizontal stretch image and then vertical folding image, repeats the process Until the position of all pixels all changes.

7. the main algorithm step of diffusion encryption according to claim 3, which is characterized in that the expansion in the step (2b) Scattered algorithm is broadly divided into:

(2b1): the XOR between pixel；

(2b1): increase modular arithmetic between the pixels.

Technical field:

The present invention relates to Encryption Algorithm field, specially a kind of double-encryption algorithm for iris feature protection.

Background technique:

With becoming increasingly popular for internet concept, personal information security is become more and more important.Biological identification technology is logical The analysis mankind intrinsic physiology or behavioural characteristic are crossed to protect the important way of personal information.The biological property of human body mainly wraps Fingerprint is included, face, iris, sound, gait, signature etc..In recent years, it is obtained using fingerprint and face as the biological identification technology of representative It is widely applied.In public safety field, but there are still some limitations in application process, the uniqueness of iris recognition and Stability compensates for these deficiencies.

In many cases, iris may be the bio-identification function that can uniquely identify identity.A series of international research Show that iris recognition is current most safe, most accurate recognition methods.With fingerprint error rate 0.8%, face error rate about 2% It compares, iris error rate can be down to 1%.Omnipotent iris function is the highest level of current biological identification technology.Academia and quotient Increasingly pay attention to the identity recognizing technology extracted based on iris feature in boundary.Iris recognition is gradually applied to high safety performance Certain departments, such as banking system and release mechanism and the more demanding environment of some pairs of authentications.Iris recognition safety Property raising to maintenance society and financial security play an important role.

In network transmission process, due to the insecurity of iris image information, malicious attacker has an opportunity to reveal or break Bad original image information.Since iris image is unique and immutable, once iris image is stolen, our privacy letter There may be the risks disclosed for a long time for breath.It is arranged in face of the malicious sabotage of iris image information and the clumsiness of victim's personal information Diction, the means for improving iris image safety are still problem in the urgent need to address.

Summary of the invention:

The purpose of the present invention is in view of the drawbacks of the prior art, provide a kind of double-encryption calculation for iris feature protection Method, to solve the problems, such as that above-mentioned background technique proposes.

To achieve the above object, the invention provides the following technical scheme: a kind of double-encryption for iris feature protection Algorithm, comprising the following steps:

Step (1): the chaotic key sequence of iris region Feature Mapping is used for using chaotic function building；

Step (2): the first re-diffusion Encryption Algorithm；

Step (3): the second re-diffusion Encryption Algorithm；

Step (4): parameter value imports reverse decryption iris region.

As a preferred technical solution of the present invention, utilize chaotic function building for iris in the step (1) The chaotic function feature of the chaotic key sequence of provincial characteristics mapping are as follows:

Feature (1a): sensitive to primary condition；

Feature (1b): must be Topologically mixing structure；

Feature (1c): at least one intensive periodic orbit.

As a preferred technical solution of the present invention, the master of the spread spectrum encryption in the step (2) and the step (3) Algorithm steps are wanted to be divided into:

Step (2a): scramble information is carried out to plaintext by common scrambling algorithm；

Step (2b): calculating is diffused to image pixel by common broadcast algorithm.

Spread spectrum encrypted feature as a preferred technical solution of the present invention, in the step (2) and the step (3) Are as follows:

Assuming that the pixel sequence for the original plaintext image to be encrypted by P (k) | k=1,2 ..., m } indicate；Chaotic key Sequence is indicated by W；Step (2) diffusion encryption after obtain ciphertext image pixel sequence by Q (k) | k=1, 2 ..., m } it indicates；Step (3) diffusion encryption after obtain final ciphertext image pixel sequence by R (k) | k=1, 2 ..., m } it indicates:

Feature (3a): in the diffusion ciphering process of step (3), without straight between final ciphertext R (k) and original plaintext P (k) Connect connection；

Feature (3b): W (k) can not be inverted using the encryption formula of step (3)；

Feature (3c): in each ciphering process, there are XOR operations and non-linear " mould " to transport between ciphertext and plaintext It calculates.

Reverse decryption iris region algorithm characteristics as a preferred technical solution of the present invention, in the step (4) Are as follows:

Feature (4a): input decipherment algorithm main contents are chaotic key sequence, encryption parameter value and final key；

Feature (4b): initial key is identical with all parameter values during encryption and decryption processes；

Feature (4c): final decrypted image is identical with encrypted image.

As a preferred technical solution of the present invention, the scrambling algorithms in the step (2a) are divided into:

(2a1): Arnold conversion scrambling: the image for being N × N for size, the home position [x of pixel₀,y₀] logical Cross the new location of pixels [x of reversible 2-dimensional matrix acquisition₁,y₁]；

(2a2): Baker transformation scrambling: mapping image by horizontal stretch image and then vertical folding image, and repeating should Process all changes until the position of all pixels.

As a preferred technical solution of the present invention, the broadcast algorithm in the step (2b) is broadly divided into:

(2b1): the XOR between pixel；

(2b1): increase modular arithmetic between the pixels.

Beneficial effects of the present invention: the characteristic information in order to protect iris image, we use chaos encryption pattern die first Iris region is pasted, to protect the iris information during network, is then encrypted using dual diffusion.The chaotic maps of neotectonics produce Raw sequence Distribution value is stronger, and chaos characteristic is complex, combining encryption algorithm, and the pixel distribution of iris image can be more Discrete and uniform, the superior performance of each index can be effective against common attack.By histogram analysis picture adjacent with image Correlation between element combines, and fully meets the security requirements of encryption method, is increasingly rooted in the hearts of the people to current information security Development under overall situation has very high researching value and meaning.

Detailed description of the invention:

Fig. 1 is file data Fusion Model flow chart of the present invention；

Fig. 2 is this algorithm simulating result schematic diagram；

Fig. 3 and 4 is the direction phase diagram of the adjacent pixel from iris plaintext image and iris ciphertext image.

Specific embodiment:

The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawing, so that advantages and features of the invention energy It is easier to be understood by those skilled in the art, so as to make a clearer definition of the protection scope of the present invention.

The present invention provides a kind of technical solution: a kind of double-encryption algorithm for iris feature protection:

The following steps are included:

Step (1): the chaotic key sequence of iris region Feature Mapping is used for using chaotic function building, wherein chaos letter It is several to be characterized in that:

(1a): sensitive to primary condition；

(1b): must be Topologically mixing structure；

(1c): at least one intensive periodic orbit；

Step (2): the first re-diffusion Encryption Algorithm spreads the step of encrypting are as follows:

(2a): scramble information is carried out to plaintext by common scrambling algorithm, scrambling algorithm mainly has:

(2a1) Arnold conversion scrambling: the image for being N × N for size, the home position [x of pixel₀,y₀] pass through New location of pixels [the x that reversible 2-dimensional matrix obtains₁,y₁]；

(2a2) Baker transformation scrambling: mapping image by horizontal stretch image and then vertical folding image, and repeating should Process all changes until the position of all pixels.

(2b): calculating is diffused to image pixel by common broadcast algorithm, broadcast algorithm mainly has:

XOR between (2b1) pixel；

(2b1) increases modular arithmetic between the pixels.

Step (3): the second re-diffusion Encryption Algorithm spreads encryption and is characterized in that:

Assuming that the pixel sequence for the original plaintext image to be encrypted by P (k) | k=1,2 ..., m } indicate；Chaotic key Sequence is indicated by W；Step (2) diffusion encryption after obtain ciphertext image pixel sequence by Q (k) | k=1, 2 ..., m } it indicates；Step (3) diffusion encryption after obtain final ciphertext image pixel sequence by R (k) | k=1, 2 ..., m } it indicates:

Feature (3a): in the diffusion ciphering process of step (3), final ciphertext R (k) and original plaintext [x₀,y₀] between do not have Directly contact；

Feature (3b): W (k) can not be inverted using the encryption formula of step (3)；

Feature (3c): in each ciphering process, there are XOR operations and non-linear " mould " to transport between ciphertext and plaintext It calculates.

Step (4): parameter value imports reverse decryption iris region, and decrypting feature is:

It is chaotic key sequence, encryption parameter value and final key that (4a), which inputs decipherment algorithm main contents,；

Initial key is identical with all parameter values during (4b) encryption and decryption processes；

(4c) final decrypted image is identical with encrypted image.

The size of key space is to measure the important indicator of the anti-attack ability of encipherment scheme.If key space is too small, Encipherment scheme is easy thoroughly to be attacked, and safety is caused to reduce.One good Encryption Algorithm, key space should be enough Greatly, to resist exhaustive attack.Data of the double precision datum in thirty-two bit computer are stored as 64, key space 2⁶⁴×2⁶⁴ =2¹²⁸Dimension.Even if attacker's 100,000,000 keys of attack per second, it is also desirable to 10¹⁴Nian Caineng exhausts entire key space.If it is considered that Reference value, then key space will be bigger and needs the more time.Therefore, the key for the double-encryption algorithm that this patent is proposed Space is safe for exhaustive attack.

The design of algorithm and safety are closely related.Algorithm of good performance can judge to mark according to various known attacks It is quasi-.Select iris figure to encrypt it.Simulation result is as shown in Figure 2.Fig. 2 (a) and Fig. 2 (d) respectively illustrate original image and its Histogram.Fig. 2 (b) and Fig. 2 (e) respectively illustrate encrypted image and its histogram.Fig. 2 (c) and Fig. 2 (f) respectively illustrate solution Close image and its histogram.As can be seen that the histogram distribution of all pixels is very uneven in original image.Encrypt iris figure As intermediate region pixel histogram distribution have good linear relationship, and do not have for encryption iris image statistical analysis Attack provides any clue.Therefore, the Statistical Analysis Attacks to encryption iris image can be effectively prevented.

From level, vertical and diagonal randomly chooses the N in image to adjacent pixel, to test plaintext image and close The correlation of adjacent pixel between texts and pictures picture.

Fig. 3 and 4 is the direction phase diagram of the adjacent pixel from iris plaintext image and iris ciphertext image.Experiment is in rainbow The level of film plaintext image and iris ciphertext image, vertically and diagonally adjacent random collecting 2000 is to adjacent pixel.Fig. 3 shows The pixel for having gone out consecutive points in iris plaintext image is almost equal.The pixel that Fig. 4 shows consecutive points in iris ciphertext image is bright Aobvious difference.

The adjacent pixel of iris plaintext image is highly relevant, and related coefficient is close to 1.Adjacent pixel in iris ciphertext image Low correlation coefficient charts obviously literary statistical nature has been diffused as random ciphertext.The iris ciphertext image that this paper algorithm obtains reaches The purpose of adjacent pixel correlation is destroyed, so that ciphertext has better random distribution characteristic.

The embodiments described above only express several embodiments of the present invention, and the description thereof is more specific and detailed, but simultaneously It cannot therefore be construed as limiting the scope of the patent.It should be pointed out that coming for those of ordinary skill in the art It says, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to protection of the invention Range.