WO2014089843A1

WO2014089843A1 - Method and device for data encryption and decryption

Info

Publication number: WO2014089843A1
Application number: PCT/CN2012/086705
Authority: WO
Inventors: 桂小林; 黄汝维; 刘阳; 魏广福; 晏鹏
Original assignee: 华为技术有限公司
Priority date: 2012-12-14
Filing date: 2012-12-14
Publication date: 2014-06-19
Also published as: CN104040935B; CN104040935A

Abstract

Disclosed are a method and device for data encryption and decryption. The method generates a path from a root node of a random tree to a leaf node corresponding to data to be encrypted according to a user key and the data to be encrypted, encrypts the data to be encrypted, restores the path from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key, and decrypts the data to be encrypted. The advantages of isotonicity, security, less calculation and storage load burden, small influence of a data domain variation on a calculation load and the like can be realized.

Description

Method and device for data encryption and decryption

Technical field

The invention belongs to the field of software algorithms, and in particular relates to a method and a device for data encryption and decryption. BACKGROUND OF THE INVENTION Cloud computing, as a new type of network computing model, provides users with on-demand IT services (computing, storage, applications, etc.) in a more economical manner than traditional IT. Since the development concept of cloud computing is in line with the current trend of low-carbon economy and green computing, it has been strongly promoted and promoted by governments and enterprises around the world, and is bringing about tremendous changes in the computing and business fields. However, in the already implemented cloud computing services, privacy security issues have been a concern and have become one of the main factors hindering the development and promotion of cloud computing. The user's privacy data includes sensitive information (such as personal health status, financial information, company important documents, etc.) that can be used to identify or locate personal information (such as phone numbers, addresses, and credit card numbers). The privacy security issue of cloud computing stems from the characteristics of cloud computing data outsourcing and service leasing. When user data is stored in the cloud environment, people lose direct control over the data, which may lead to the leakage and abuse of personal privacy data.

Encryption is a commonly used method to protect user confidential data. Encryption technology that supports relational operations is an encryption method. It guarantees data security through encryption. At the same time, encrypted data can support relational operations, so that the ciphertext can be directly scoped. Retrieve, sort, etc.

Agrawal et al. proposed a preserved symmetric encryption algorithm OPES based on the idea of bucket partitioning and distributed probability mapping, which supports various relational operations on encrypted numerical data. Boldyreva et al. proposed a preservation symmetry based on the binary search and hypergeometric probability distribution. The encryption algorithm OPSE supports various relational operations on encrypted data. The advantage of the above two types of preserving encryption methods is order preservation, that is, the ciphertext reflects the size relationship of the plaintext, thereby facilitating the service provider to index the ciphertext data. , speed up the search, and easy to implement a variety of relational operations.

The disadvantage of Agrawal et al. is that the computational load of bucket partitioning is large when the domain is large, and when the attack of the known plaintext is faced, when the number of buckets in the bucket of the input distribution and the corresponding output distribution is sufficient. , can be solved by solving the equation. The method of Boldyreva et al. requires a large number of combination operations when calculating the hypergeometric probability, and its computational load is large. In summary, the shortcomings of the order-preserving encryption algorithm It is not that they can meet the requirements of efficiency and security at the same time. Technical Problem An object of the embodiments of the present invention is to provide a method for data encryption and decryption, which can achieve the advantages of order-preserving, security, less load on calculation and storage, and less influence of data domain changes on computation load. A first aspect of the technical solution, a data encryption method, the method comprising:

Converting the data to be encrypted from the plaintext string to the American Standard Code for Information Interchange (ASCII) code, and converting the number of bits of the converted ASCII code to a multiple of a preset domain value, the preset domain value being each time The number of bits of the encrypted ASCII code;

Determining a height of the random tree according to the preset domain value, and generating a path from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted, and at the leaf node A random number is selected within the range of the associated interval to form the ciphertext of the data to be encrypted.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the generating, by the user key and the data to be encrypted, the path from the root node of the random number to the leaf node corresponding to the data to be encrypted is specifically :

Determining the number of layers of the random tree, the number of divided copies, the user key, the data to be encrypted, and the minimum and maximum values of the interval to be divided; the number of divided segments is divided into equal intervals to be divided Number of copies; wherein, the length of each layer of the random tree is the length of the range plus the length of the interval field;

Generating a seed of the random tree according to the user key and the US standard information exchange standard code of the current node;

And each of the range of values is equally divided into the number of divided parts, and a random number is generated by a seed of the random tree, where the random number is used to generate a spacing field, and the number of divided parts and the selected sub-range of each interval field Node, at the same time, the length of the total interval domain after the division is equal to the length of the interval domain before the division;

Determining a node position of the encrypted data, where a minimum value of the node position is a sum of three values, wherein the three values are respectively a minimum value of a random tree above the node position, and a value to the node position The sum of the domain interval values, the sum of the interval domain values to the node locations;

Determining whether the node location is the selected child node, and if so, the node location is the most The large value is the sum of three values, the three values being the minimum value of the node position, the value interval value of the node position, and the value of the interval field at the node position;

If not, the maximum value of the node position is the sum of two values, the two values being the minimum of the node position and the value interval value of the node position.

With reference to the first aspect, in a second possible implementation manner of the first aspect, the selecting, in the range of the interval to which the leaf node belongs, selecting a random number, the ciphertext forming the data to be encrypted includes: When the encrypted data is located at the last layer of the random number, a random number is selected within the interval of the child node where the data to be encrypted is located to form the ciphertext of the data to be encrypted.

In a second aspect, a method for data decryption, the method comprising:

Obtaining a user key and data to be decrypted;

And recovering, according to the user key and the data to be decrypted, the path from the root node of the random tree to the leaf node corresponding to the data to be encrypted, and decrypting the data to be decrypted;

The decrypted data is converted to a plain text string after the padding value is removed.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the recovering, according to the user key and the data to be decrypted, the corresponding root node of the random tree to the data to be decrypted The path of the leaf node is specifically:

Determining a height of the random tree, a number of divisions, the user key, the data to be decrypted, and a minimum value and a maximum value of the interval to be divided; the number of divisions is an interval that divides the sections to be divided equally The number of copies, where the length of each layer of the random tree is the length of the range plus the length of the interval field;

Dividing the interval to be divided into the number of divided segments, and generating a random number by using a seed of the random tree, where the random number is used to generate a segment interval field to be divided, and the number of segments in the interval domain And the selected child node, at the same time, the length of the total interval domain after the division is equal to the length of the interval domain before the segmentation;

Determining, according to the minimum value of the range of each child node, a location where the ciphertext is located; calculating, according to the location of the ciphertext, an American Standard Code for Information Interchange of the current node, according to the user key and the current node The US Information Exchange Standard Code generates a seed of a random tree;

Generating a random number according to the seed of the random number, and dividing, by the random number, a section to be divided into the number of nodes to be divided into two area values, where the two area values are total value ranges of the next layer of random trees And under The total interval field value of a random tree;

Determining a node position of the data to be decrypted, wherein a minimum value of the node position is a sum of three values, wherein the three values are respectively a minimum value of a random tree of the node position, and the node position is The sum of the range interval values, the sum of the interval interval values to the node locations;

Determining whether the node location is the selected child node, and if so, the maximum value of the node location is a sum of three values, wherein the three values are respectively a minimum value of the node location, and the node location a value range value, the value of the interval field at the node location;

A third aspect, a data encryption device, where the device includes:

a first converting unit, configured to convert the data to be encrypted from the plaintext string into the American Standard Code for Information Interchange (ASCII) code, and convert the number of bits of the converted ASCII code into a multiple of a preset domain value, the preset The domain value is the number of bits of the ASCII code that is encrypted each time;

An encryption unit, configured to determine a height of the random tree according to the preset domain value, and generate a path from a root node of the random tree to a leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted, and Selecting a random number within a range of values to which the leaf node belongs, forming a ciphertext of the data to be encrypted.

With reference to the third aspect, in a first possible implementation manner of the third aspect, the step of performing, in the cryptographic unit, generating, according to the user key and the data to be encrypted, generating a root node from the random number to the data to be encrypted The path of the leaf node is specifically:

a first determining unit, configured to determine a number of layers of the random tree, a number of divided shares, the user key, the to-be-encrypted data, and a minimum value and a maximum value of the to-be-divided interval; Describe the number of copies divided into equal intervals; wherein, the length of each layer of the random tree is the length of the range plus the length of the interval field;

a first generating unit, configured to generate a seed of the random tree according to the user key and the US information exchange standard code of the current node;

a first dividing unit, configured to divide the each of the range of values into the number of divided segments, and generate a random number by using a seed of the random tree, where the random number is used to generate a spacing domain, where each interval domain is Dividing the number of copies and the selected child nodes, and making the total length of the divided interval fields equal to the length of the interval before the segmentation; a second determining unit, configured to determine a node location of the encrypted data, where a minimum value of the node location is a sum of three values, where the three values are respectively a minimum value of a random tree above the node location, a sum of value range values to the node position, a sum of interval field interval values to the node position; a first determining unit, configured to determine whether the node position is the selected child node, and if yes, The maximum value of the node position is the sum of three values, the three values are respectively the minimum value of the node position, the value range interval value of the node position, and the value of the interval field at the node position ;

With reference to the third aspect, in a second possible implementation manner of the third aspect, the performing step is performed by the cryptographic unit, and a random number is selected in a range of values to which the leaf node belongs to form the data to be encrypted. The ciphertext in the ciphertext includes:

When the data to be encrypted is located in the last layer of the random number, a random number is selected in the range of the sub-node where the data to be encrypted is located to form the ciphertext of the data to be encrypted.

A device for decrypting data, the device comprising:

An obtaining unit, configured to acquire a user key and data to be decrypted;

a decrypting unit, configured to recover the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key and the data to be decrypted, and decrypt the data to be decrypted; a conversion unit, configured to convert the decrypted data into a plaintext string after removing the padding value. With reference to the fourth aspect, in a first possible implementation manner of the fourth aspect, the performing step in the decrypting unit recovers the leaf corresponding to the to-be-decrypted data from the root node of the random tree according to the user key The path of the node is specifically:

a third determining unit, configured to determine a height of the random tree, a number of divided shares, the user key, the to-be-decrypted data, a minimum value and a maximum value of the to-be-divided interval; The number of copies of the interval to be divided into equal intervals, wherein the length of each random tree is the length of the range plus the length of the interval;

a second generating unit, configured to generate a seed of the random tree according to the user key and the US information exchange standard code of the current node;

a second dividing unit, configured to divide the to-divided interval into equal intervals, and generate a random number by using a seed of the random tree, where the random number is used to generate each interval interval to be divided, The number of divided partitions of the interval domain and the selected child nodes, and the total length of the partitioned partitions, etc. The length of the interval before the segmentation;

a second determining unit, configured to determine, according to a minimum value of a range of each child node, a location where the ciphertext is located;

a calculating unit, configured to calculate, according to the location where the ciphertext is located, a US information exchange standard code of the current node, and generate a seed of the random tree according to the user key and the US standard information exchange standard code of the current node;

The third dividing unit is configured to generate a random number according to the seed of the random number, and divide, by the random number, the to-divided interval in which the number of nodes is located into two regional values, where the two regional values are the next random tree The total value of the field and the total interval field value of the next random tree;

a fourth determining unit, configured to determine a node location of the decrypted data, where a minimum value of the node location is a sum of three values, where the three values are respectively a minimum value of a random tree of the layer at the node location, a sum of the value range values of the node locations, a sum of the interval field values to the node locations; a third determining unit, configured to determine whether the node locations are the selected child nodes, and if so, The maximum value of the node position is the sum of three values, the three values are respectively the minimum value of the node position, the value range interval value of the node position, and the value of the interval field at the node position ;

If not, the maximum value of the node position is the sum of two values, the two values being the minimum value of the node position and the value interval value of the node position. Advantageous Effects Compared with the prior art, the embodiment of the present invention encrypts the data to be encrypted by generating a path from a root node of the random tree to a leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted. And recovering, according to the user key, the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted, and decrypting the data to be decrypted. The advantages of order-preserving, security, computational and storage load burden, and data domain changes have little impact on the computational load. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below. Obviously, the drawings in the following description are only some of the present invention. For the embodiments, those skilled in the art can obtain other drawings according to the drawings without any creative labor. 1 is a flowchart of a method for encrypting according to Embodiment 1 of the present invention;

2 is a flowchart of a method for encrypting according to Embodiment 2 of the present invention;

3 is a flowchart of a method for encrypting and decrypting according to Embodiment 3 of the present invention;

4 is a schematic diagram of a method for encrypting and decrypting according to Embodiment 3 of the present invention;

FIG. 5 is a structural diagram of a device for a data encryption device according to Embodiment 4 of the present invention; FIG.

6 is a structural diagram of a device of a data encryption device according to Embodiment 4 of the present invention;

7 is a structural diagram of a device of a data decryption apparatus according to Embodiment 5 of the present invention;

FIG. 8 is a structural diagram of a device for decrypting a data provided by Embodiment 5 of the present invention; FIG.

9 is a structural diagram of an apparatus for a data encryption device according to Embodiment 6 of the present invention;

FIG. 10 is a structural diagram of an apparatus for a data decryption apparatus according to Embodiment 7 of the present invention. Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Embodiment 1

Referring to FIG. 1, FIG. 1 is a flowchart of a method for data encryption according to Embodiment 1 of the present invention. As shown in Figure 1, the method includes the following steps:

Step 101: Convert the data to be encrypted from a plaintext string to an American Standard Code for Information Interchange (ASCII) code, and convert the number of bits of the converted ASCII code into a multiple of a preset domain value, the preset domain value. Is the number of bits of the ASCII code that is encrypted each time;

In this step, a string of plain text strings input by the user is received, and the plaintext string is converted into a US standard code exchange standard code in advance. Defining a definition field, the value of the definition field is the number of bits of the US Standard Code for Information Interchange per encryption, for example, pre-defining a 12-bit US exchange standard code each time, the converted US information exchange standard The number of bits in the code is rounded to a multiple of 12. Specifically, suppose the user enters a string of characters as ABCDEF ....., converts each character into ASCII code, and makes a 3-digit ASCII code. For example, the ASCII code of A is 65, which is 065, and the support is random. The number of the domain is 12, and the height of the random number is 6 layers, that is, each layer encrypts 2 digits of ASCII code, and each time a total of 12 bits are encrypted. The data to be encrypted converted into ASCII code is taken 22 bits at a time, and a 22 identifier is added after the 22-bit ASCII code to make 24 bits, that is, the random tree encryption algorithm is executed twice each time, and the 24-bit ASCII code is encrypted. When there are only ten ASCII codes left, add 00 after the 10-digit ASCII code, add 10 random numbers, and add 10 to identify the number of bits of the ASCII code of the data to be encrypted, and make it into 24 bits for encryption. When there is only one ASCII code left, add 00 after an ASCII code, add a 19-bit random number, and add 01 to identify the number of bits of the ASCII code of the data to be encrypted, and make it into 24 bits for encryption. And so on.

Step 102: Determine a height of the random tree according to the preset domain value, and generate a path from a root node of the random tree to a leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted, and A random number is selected in the range of the interval to which the leaf node belongs, and the ciphertext of the data to be encrypted is formed.

In this step, if the pre-set domain is a 12-bit US standard code exchange standard code, and the 2-digit US standard code exchange standard code is stored in advance, the height of the random number is 6, that is, according to the preset domain. The value determines the height of the random number.

In this step, the path from the root node of the random number to the leaf node corresponding to the data to be encrypted is generated according to the user key and the data to be encrypted:

Determining the number of layers of the random tree, the number of divisions, the user key, the data to be encrypted, and the minimum and maximum values of the interval to be divided; the number of divisions is divided into equal intervals to be divided Number of copies; wherein, the length of each layer of the random tree is the length of the range plus the length of the interval field;

Specifically, determining a height level of the random tree, dividing the number of copies num, the user key key, the data to be encrypted X, a minimum value min and a maximum value max of the interval to be divided, the num is The number of copies of the interval to be divided into equal intervals, vf is the value range of the interval to be divided, and gf is the interval domain of the interval to be divided.

Specifically, when the random tree is located at the zeroth layer level=n, n=0, the random tree seed ran_root=key; when level=n, n=l, 2....1evel-2, Ran—root=key+ ^x « , Where n=0, ^=0, n=l, the zeroth layer random number encrypted data to be encrypted; n=2, the zeroth layer random number and the first layer random number encrypted data to be encrypted; n =level-2, the zeroth layer random number, the first layer random number.... The level-2 layer encrypted data to be encrypted.

Specifically, according to the ran-root generation interval domain gf, the interval domain gf splitting number m, and randomly selecting m child nodes from num child nodes, f _an dom(k _ey + _Xi )≤i is satisfied

m + 1

^ random (key + . ) > 1

i =l

Specifically, it is determined that the position of X is i, satisfies x>xi-l and x≤xi, min _n = min _n _ _x + (i _ 1) * + dd _n * random(key + Xj )

d _n = vf _n- i/num, dd _n = gf _n-1 , vf _n-1 = ( max _n-1 - min _n-1 ) *r _n small gf _n-1 = ( max _n-1 - min _N-1 ) * ( lr _n-1 ), r _n-1 is a random number generated based on the value of ran-root at the n-1th layer.

Specifically, determining whether i is any one of the m child nodes, and if yes,

Max _n =min _n + d _n + dd _n *random(key+Xi) , no shell 'J , max _n =min _n + d _n .

Specifically, the encryption algorithm refers to algorithm 1.

The ciphertext of the to-be-encrypted data is included in the range of the range to which the leaf node belongs, and the ciphertext of the data to be encrypted includes:

When the data to be encrypted is located at the last layer of the random number, the child where the data to be encrypted is located Within the interval of the node, a random number is selected to form the ciphertext of the data to be encrypted. Specifically, when level=n, n=level-1, the ciphertext ciphertext of the to-be-tightened data x is ciphertext=min,

+ (max _n - min _n )* randorr^key+^

Algorithm 1 Encryption Algorithm Enc()

Input: minimum interval to be divided min, maximum max, number of random tree levels, number of divisions num, key key, force secret data x

For L=0 to level;

If L==0 then

Ran—root=key ; //generate the seed of the random number

Generating a value range vf and a spacer field gf according to ran_root;

Min=min; max=min+|vf|; dd=|gf|;〃interval

6:

7: ran_root=key+ the value of the current node;

8: generating a value field vf and a space field gf according to the ran-root split data field (min, max);

11 Determine the position of X as i, satisfy χ>χ _{μ ι} and χ<χι

12 min=min+(x-1)*d+dd* '∑ random(key + χΛ;

=l

13 Generate a random number r according to ran—root;

14 If x==Xi then

15 max=min+d +dd*random(key+Xi);

16 Else

17 max=min+d;

18 End If

16 dd= d*(l-r);

17 End If

18 End for

19 ciphertext=min+(max-min) * random(key+x); The core part of the invention constructs a random data structure - a random tree. The random tree is a multi-forked tree whose height is determined by the domain. Each node in the tree corresponds to a point in the domain and occupies a sub-interval in the value field. The sub-node interval is a kind of parent node interval. Randomly divided. The encryption tree algorithm OPEART based on random tree has the following characteristics: (1) In the process of encryption or decryption, it is not necessary to generate an entire tree, but only a path from the root node to the leaf node in the spanning tree, and the calculation load is small; (2) The computational load does not change as the domain changes, and is suitable for applications that define large or dynamic domains;

(3) No need to build an index, saving the data owner's computing and storage load. The present invention is a cryptographic algorithm, ciphertext has order preservation, supports relational operations, and has IND-DNCPA security.

The embodiment of the present invention generates the path to be encrypted from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted, and recovers the data to be encrypted according to the user key. The path from the root node of the random tree to the leaf node corresponding to the data to be encrypted is used to decrypt the data to be encrypted. The advantages of order-preserving, security, computational and storage load burden, and data domain changes have little impact on the computational load.

Embodiment 2

Referring to FIG. 2, FIG. 2 is a flowchart of a method for data decryption according to Embodiment 2 of the present invention. As shown in Figure 2, the method includes the following steps:

Step 201: Obtain a user key and data to be decrypted;

Step 202: Recover the path from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key and the data to be decrypted, and decrypt the data to be decrypted;

Recovering the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key is specifically:

Specifically, determining a height level of the random tree, a number of divisions num, the user key key, a ciphertext of the data to be encrypted, a minimum value min and a maximum value max of the interval to be divided, the num is The number of copies of the interval to be divided is equally divided, vf is a value range of the interval to be divided, and gf is a interval domain of the interval to be divided.

Specifically, when the random tree is located at the zeroth layer level=n, n=0, the random tree seed ran_root=key. Dividing the interval to be divided into the number of divided segments, and generating a random number by using a seed of the random tree, where the random number is used to generate a segment interval field to be divided, and the number of segments in the interval domain And the selected child node, at the same time, the length of the total interval domain after the division is equal to the length of the interval domain before the segmentation; Specifically, according to the ran-root generation interval domain gf, the interval domain gf splitting number m and randomly selecting m child nodes from num child nodes, f _an dom(k _ey + _Xi )≤i satisfies random (key 1 according to a minimum value of a range of each child node, determining a location at which the ciphertext is located; a position equal to the ciphertext value minus a minimum value of the child node and then subtracting a space interval before the child node The value obtained after the value is divided by the interval of the value field division of the child node;

Specifically, the lower limit of the range in which each node is located is min ( x _k ), where ( 0, num-1 ), the position of the ciphertext is determined to be i, the ciphertex ≤ min ( x _k ) is satisfied, and ciphertex > min

( k-i ),

!·- 1

x _n = (ciphertex - min(3⁄4_ ₁ ) - dd _n * ^ random (key + Xj )) I d _n

J=l calculates a US standard information exchange standard code of the current node according to the location of the ciphertext, and generates a seed of the random tree according to the user key and the current information exchange standard code of the current node;

When level=n, n=l, 2....1evel-2, the ran_root=key+ ^x " ,

Where n=0, ^=0, n=l, the zeroth layer random number encrypted data to be encrypted; n=2, the zeroth layer random number and the first layer random number encrypted data to be encrypted; n =level-2, the zeroth layer random number, the first layer random number.... The level-2 layer encrypted data to be encrypted.

Generating a random number according to the seed of the random number, and dividing, by the random number, a section to be divided into the number of nodes to be divided into two area values, where the two area values are total value ranges of the next layer of random trees And the total interval field value of the next random tree;

Determining a node position of the decrypted data, wherein a minimum value of the node position is a sum of three values, wherein the three values are respectively a minimum value of a random tree above the node position, and a value to the node position The sum of the domain interval values, the sum of the interval domain values to the node locations;

specific,

I-l

Min _n = min _η _ _λ + (i _ 1) * + dd _n * ^ random(key + Xj )

( max _n _r min _n _i ) *r _n small gf _n _ ₁₌ ( max _n _r min _n _i ) * ( lr _n-1 ), r _n-1 is a random number generated from the value of ran-root at the n-1th layer.

Max _n =min _n + d _n ten dd _n *random(key+Xi) , no l l , max _n =min _n + d _n .

Encryption algorithm reference algorithm 2.

Algorithm 2 decryption algorithm Dec()

Input: minimum interval to be divided min, maximum max, number of random tree levels level, number of divisions num, key key, data to be decrypted val

1: For L=0 to level

2: If L==0 then

3: ran_root=key; //generate the seed of the random number

4: Generate a value range vf and a spacer field gf according to ran_root;

5: min=min; max=min+|vf|; dd=|gf|;

6: Else

7: ran_root=key+ the value of the current node;

8: generating a value field vf and a space field gf according to the ran_root split data field (min, max);

9: d=|vfl/num;

10: According to ran-root, generate the partition number gf split number m and select m sub-nodes

{x ₀ ,...,x _m }(i ^ [l,n]), W>3⁄4-∑random(key + x _i ) < \ and ∑ random(key + x _i ) >\;

i=\ i=\

11 : Assume that the lower limit of the range of each node is min(x _k ) (k≡ [0,m]), and judge the bit of x

Set i, satisfying: val≤min (x _k) and _{val> min (x k-1} ),

12: x=(val-min-dd* '∑ random(key + x _f ) )/d;

13: Generate a random number r according to key and x;

14: If x==Xi then

15: max=min+d*r+dd*random(key+Xi);

16: Else

17: max=min+d*r;

18: End If

19: dd= d*(l-r);

20: End If

21: plaintext=plaintext+x; //string connection 22: End For

Step 203: Convert the decrypted data into a plaintext string after removing the padding value.

In this step, after the padding value such as 00 or 22 is eliminated, the ASCII code converted by the plaintext string is obtained, and then converted into a plaintext string by the ASCII code.

The core part of the invention constructs a random data structure - a random tree. The random tree is a multi-forked tree whose height is determined by the domain. Each node in the tree corresponds to a point in the domain and occupies a sub-interval in the value field. The sub-node interval is a kind of parent node interval. Randomly divided. The encryption tree algorithm OPEART based on random tree has the following characteristics: (1) In the process of encryption or decryption, it is not necessary to generate an entire tree, but only a path from the root node to the leaf node in the spanning tree, and the calculation load is small; (2) The computational load does not change with the change of the domain. It is suitable for applications with large or dynamic domains. (3) No need to establish an index, which saves the data owner's computing and storage load. The present invention is a cryptographic algorithm, ciphertext has order preservation, supports relational operations, and has IND-DNCPA security.

Embodiment 3

Referring to FIG. 3, FIG. 3 is a schematic diagram of a method for data encryption and data decryption according to Embodiment 3 of the present invention. As shown in Figure 3,

Step 301: Convert the plaintext string into the American Standard Code for Information Interchange (ASCII) code, and round the number of bits of the converted ASCII code to a multiple of 12, where 12 is the number of bits of the ASCII code that is encrypted each time; When encrypted to 12-bit ASCII, the total length of the zeroth-order random tree can be 10 ¹⁵ . Step 302: Determine, according to 12, that the height of the random tree is 6, and generate a path from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted, and belong to the leaf node to which the leaf node belongs. Select a random number in the interval range to form the ciphertext of the data to be encrypted; set the converted ASCII code to 012345678901, and encrypt the 2-bit ASCII code in each layer of the random tree. Specifically, when the random tree is at the zeroth layer level= When n, n=0, the random tree seed ran_root=key, according to the seed of the random tree, divides the total length of the zeroth random tree into the value domain vf. And the interval field gf. , vf ₀₊ gf ₀ =10 ¹⁵ , will be the value range vf. Divided into 100 copies, and the interval domain gf is generated based on the seeds of the random tree. Segmentation The number m and the selected child node m are such that the total length of the partitioned partition is equal to the length of the interval before the partition.

The zeroth layer of data to be encrypted is 01 and will be placed in the first range of the range 01, as shown in Figure 4.

Determine whether the interval of 01 belongs to the selected child node. If yes, the maximum value of the 01 interval is the interval field of the range +01 of max=min+01; if not, the maximum value of the interval of the Bay' J 01 is max=min+ The range of 01. The value range of 01 is vf. /100.

In the interval of the zeroth layer 01, a first layer random number is generated according to the seed ran_root=key+01 of the random tree, and the interval value of the zeroth layer 01 interval is divided according to the random number of the first layer. The value range of the first layer vf^ the interval field gfi, where the 01 interval value is equal to the maximum value of the 01 interval minus the minimum value of the 01 interval, vfi + gfi = 01 interval value.

Divide νί equal intervals into 100 parts, and divide the number of partitions of the first layer and the selected child nodes according to the first layer random number. The first layer of data to be encrypted is 23 and will be placed in the 23rd range of the partition.

Determine whether the interval of 23 belongs to the selected child node. If yes, the maximum value of the 23 interval is the interval domain of the range +23 of max=min+23; if not, the maximum value of the interval of the Bay' J 23 is max=min+ The range of 23 values. The range of 23 is vfi/100o

In the interval of the first layer 23, a second layer random number is generated according to the seed ran_root=key+0123 of the random tree, and the interval value of the first layer 23 interval is divided according to the random number of the second layer. The value range vf ₂ and the interval field gf _{2 of the} second layer, wherein the interval value of 23 is equal to the maximum value of the 23 interval minus the minimum value of the 23 interval, vf ₂ + gf ₂ = 23 interval value.

The vf _{2 is} equally divided into 100 parts, and the number of partitions of the second layer and the selected child nodes are divided according to the second layer random number. The second layer of data to be encrypted is 45 and will be placed in the 45th range of the division.

Determine whether the interval of 45 belongs to the selected child node. If yes, the maximum value of the 45 interval is the value i of max=min+45 or the interval i of +45 or; if not, the maximum value of the interval of the Bay ¹ J 45 is max= The value range of min+45. Range of 45 vf _2/100.

In the interval of the second layer 45, a third layer random number is generated according to the seed ran_root=key+012345 of the random tree, and the interval value of the second layer 45 interval is divided according to the random number of the third layer. The value range vf ₃ and the interval field gf _{3 of the} third layer, where the 45 interval value is equal to the maximum value of the 45 interval minus the most of the 45 interval Small value, vf ₃ + gf ₃ = 45 interval value.

The vf _{3 is} equally divided into 100 parts, and the number of partitions of the third layer and the selected child nodes are divided according to the third layer random number. The third layer of data to be encrypted is 67, which will be placed in the 67th range of the division.

Determine whether the interval of 67 belongs to the selected child node. If yes, the maximum value of the 67 interval is the value i of max=min+67 or the interval i of +67 or; if not, the maximum value of the interval of the Bay ¹ J 67 is max= The value range of min+67. Range 67 to vf _3/100.

In the interval of the third layer 67, a fourth layer random number is generated according to the seed ran_root=key+01234567 of the random tree, and the interval value of the third layer 67 interval is divided according to the random number of the fourth layer. The value range vf ₄ and the interval field gf _{4 of the} fourth layer, wherein the 67 interval value is equal to the maximum value of the 67 interval minus the minimum value of the 67 interval, vf ₄ + gf ₄ = 67 interval value.

The vf _{4 is} equally divided into 100 parts, and the number of partitions of the fourth layer and the selected child nodes are divided according to the fourth layer random number. The fourth layer of data to be encrypted is 89, which will be placed in the 89th range of the partition.

Determine whether the interval of 89 belongs to the selected child node. If yes, the maximum value of the 89 interval is the value i of max=min+89 or the interval i of +89 or; if not, the maximum value of the interval of Bay' J 89 is max= The range of values for min+89. Range of 89 vf _4/100.

In the interval of the fourth layer 89, a fifth layer random number is generated according to the seed ran_root=key+0123456789 of the random tree, and the interval value of the fourth layer 89 interval is divided according to the random number of the fifth layer. The value range vf ₅ and the interval field gf _{5 of the} fifth layer, wherein the 89 interval value is equal to the maximum value of the 89 interval minus the minimum value of the 89 interval, vf ₅ + gf ₅ = 89 interval value.

The vf _{5 is} equally divided into 100 parts, and the number of divisions of the fifth layer and the selected child nodes are divided according to the fifth layer random number. The data to be encrypted on the fifth layer is 01, which will be placed in the 01th range of the division.

Determine whether the interval of 01 belongs to the selected child node. If yes, the maximum value of the 01 interval is the interval field of the range +01 of max=min+01; if not, the maximum value of the interval of the Bay' J 01 is max=min+ The range of 01. Range of 01 vf _5/100.

Specifically, when level=n, n=5, the ciphertext of the to-be-tightened data x is ciphertext=min ₅ + (max ₅ - min ₅ )* random(key+3⁄4) ₀ 3⁄4 =01+23 +45+67+89 ( 0123456789 ).

Step 303: Restore the random tree according to the user key and the ciphertext of the data to be encrypted. Deleting the ciphertext of the data to be encrypted by the root node to the path of the leaf node corresponding to the data to be encrypted;

Specifically, according to the rules of the encryption algorithm, a random tree of the zeroth layer is generated (it is better to say that the key=key of the layer 0 is independent of the plaintext), and determine which interval of the zeroth layer the value of the ciphertext ciphertext is, according to the steps. The value of ciphertext of 202 is located in the 01 interval of the zeroth layer, that is, the OIASCII code is obtained; the first layer of the random tree is generated according to the ASCII code of 01 and the user key, and it is determined which of the random trees of the first layer is the value of the ciphertext. The interval, according to step 202, is located in the 23 interval of the first layer, that is, 23 ASCII code is obtained; according to the ASCII code of 23 and the user key, a random tree of the second layer is generated, and the value of the ciphertext is continuously determined to be located in the random tree of the second layer. Which interval, according to step 202, is located in the 45th interval of the second layer, that is, 45 ASCII code; ^ according to 45 ASCII code and user key to generate a third layer of random tree, continue to determine the value of ciphertext is located in the third layer of random Which interval of the tree, according to step 202, is located in the 67th interval of the third layer, that is, 67 ASCII code; according to the ASCII code of 67 and the user key generation The four-layer random tree continues to determine which interval of the fourth-level random tree the ciphertext value is. According to step 202, in the 89th interval of the fourth layer, 89 ASCII code is obtained; according to the ASCII code of 89 and the user key. The random tree of the fifth layer continues to determine which interval of the random tree of the fifth layer the value of the ciphertext is located. According to step 202, the 01 segment of the fourth layer obtains the OIASCII code.

Step 304: After the decrypted data to be encrypted is subjected to the erasure value.

Specifically, the last encrypted and decrypted data only needs to eliminate the padding value, because the previous encrypted decrypted data format is valid 22 bits +22 constitutes a 24-bit string.

Embodiment 4

Referring to FIG. 5, FIG. 5 is a structural diagram of a device for data encryption according to Embodiment 4 of the present invention. As shown in FIG. 5, the device includes the following units:

The first converting unit 501 is configured to convert the data to be encrypted from the plaintext string into the American Standard Code for Information Interchange (ASCII) code, and convert the number of bits of the converted ASCII code to a value of a preset domain value. The predetermined domain value is the number of bits of the ASCII code that is encrypted each time; the encryption unit 502 is configured to determine the height of the random tree according to the preset domain value, and according to the user key and The data to be encrypted is generated from a root node of the random tree to a leaf node corresponding to the data to be encrypted, and a random number is selected within the range of the leaf node to form a ciphertext of the data to be encrypted.

Specifically, the encryption unit 502 includes:

a first determining unit 601, configured to determine a number of layers of the random tree, a number of divided shares, the user key, the to-be-encrypted data, a minimum value and a maximum value of the interval to be divided; The number of copies to be divided into equal intervals; wherein, the length of each layer of the random tree is the length of the range plus the length of the interval field;

a first generating unit 602, configured to generate a seed of the random tree according to the user key and an American Information Exchange Standard Code of the current node;

a first dividing unit 603, configured to divide the each range of values into the divided number of segments, and generate a random number by using a seed of the random tree, where the random number is used to generate a spacing domain, each interval domain The number of divided parts and the selected child nodes, and the length of the total interval domain after the division is equal to the length of the interval domain before the division;

a second determining unit 604, configured to determine a node location of the encrypted data, where a minimum value of the node location is a sum of three values, where the three values are minimum values of a random tree above the node location The sum of the value interval values of the node locations, the sum of the interval field values to the node locations; the first determining unit 605, configured to determine whether the node locations are the selected child nodes, and if The maximum value of the node position is a sum of three values, the three values are respectively a minimum value of the node position, a value interval value of the node position, and the interval field is at the node position Value

Embodiment 5 Referring to FIG. 7, FIG. 7 is a structural diagram of a device for decrypting data according to Embodiment 5 of the present invention. As shown in FIG. 7, the device includes the following units:

An obtaining unit 701, configured to acquire a user key and data to be decrypted;

The decrypting unit 702 is configured to recover the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key and the data to be decrypted, and decrypt the data to be decrypted; Unit 702 includes:

a third determining unit 801, configured to determine a height of the random tree, a number of divided shares, the user key, the to-be-decrypted data, a minimum value and a maximum value of the to-be-divided interval; The number of copies of the interval interval is divided, wherein the length of each layer of the random tree is the length of the range plus the length of the interval field;

a second generating unit 802, configured to generate a seed of the random tree according to the user key and an American Information Exchange Standard Code of the current node;

a second dividing unit 803, configured to divide the interval to be divided into the number of divided segments, and generate a random number by using a seed of the random tree, where the random number is used to generate an interval interval field to be divided. The number of divisions of the interval domain and the selected child node, and the length of the total interval domain after the division is equal to the length of the interval domain before the division;

The third determining unit 804 determines, according to the minimum value of the range of each child node, the location where the ciphertext is located; the location is equal to the ciphertext value minus the minimum value of the child node, and then subtracts the location The value obtained after the interval field value before the child node is divided by the interval of the value field division of the child node;

The calculating unit 805 is configured to calculate, according to the location where the ciphertext is located, a US standard information exchange standard code of the current node, and generate a seed of the random tree according to the user key and the US exchange standard code of the current node;

a third dividing unit 806, configured to generate a random number according to the seed of the random number, and divide, by the random number, a to-divided interval in which the number of nodes is divided into two area values, where the two area values are next layer The total value range of the random tree and the total interval field value of the next random tree;

a fourth determining unit 807, configured to determine a node location of the decrypted data, where a minimum value of the node location is a sum of three values, where the three values are minimum values of a random tree above the node location The sum of the value range values of the node locations, the sum of the interval field values to the node locations; the third determining unit 808, configured to determine whether the node locations are the selected child nodes, and if The maximum value of the node position is the sum of three values, the three values being the most a small value, a value interval value of the node position, a value of the interval field at the node position; if not, a maximum value of the node position is a sum of two values, and the two values are respectively The minimum value of the node location, the value interval value of the node location.

The second converting unit 703 is configured to convert the decrypted data to be encrypted into a plaintext string after the padding value is removed.

Embodiment 6

Referring to FIG. 9, FIG. 9 is a structural diagram of a device for data encryption according to Embodiment 6 of the present invention. Referring to FIG. 9, FIG. 9 is a data encryption device 900 according to an embodiment of the present invention. The specific implementation of the device does not limit the specific implementation of the device. The device 900 includes:

A processor 901, a communications interface 902, a memory 903, and a bus 904.

The processor 901, the communication interface 902, and the memory 903 complete communication with each other via the bus 904. a communication interface 902, configured to communicate with a data decryption device;

The processor 901 is configured to execute a program.

Specifically, the program Α may include program code.

The processor 901 may be a central processing unit CPU, or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

The memory 903 is used to store the program. The memory 903 may include a high speed RAM memory and may also include a non-volatile memory such as at least one disk memory. Program A may specifically include the following code for implementing the following functions:

Converting the plaintext string into the American Standard Code for Information Interchange (ASCII) code, and multiplying the number of bits of the converted ASCII code into a multiple of a pre-set domain value, the pre-set domain value being each encrypted The number of bits in ASCII code;

Determining the height of the random tree according to the preset domain value, and according to the user key and waiting The encrypted data is generated from a root node of the random tree to a leaf node corresponding to the to-be-encrypted data, and a random number is selected within a range to which the leaf node belongs to form a ciphertext of the data to be encrypted.

Example 7

Referring to FIG. 10, FIG. 10 is a structural diagram of a device for decrypting data according to Embodiment 7 of the present invention. Referring to FIG. 10, FIG. 10 is a device 1000 for decrypting data according to an embodiment of the present invention. The specific embodiment of the present invention does not limit the specific implementation of the device. The device 1000 includes:

A processor 1001, a communication interface 1002, a memory 1003, and a bus 1004.

The processor 1001, the communication interface 1002, and the memory 1003 complete communication with each other via the bus 1004.

a communication interface 1002, configured to communicate with a data encryption device;

The processor 1001 is configured to execute program A.

In particular, program A can include program code.

The processor 1001 may be a central processing unit CPU, or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

The memory 1003 is configured to store the program eight. The memory 1003 may include a high speed RAM memory and may also include a non-volatile memory such as at least one disk memory. Program A may specifically include the following code for implementing the following functions:

Obtaining the user key and the ciphertext of the data to be encrypted;

Recovering the path from the root node of the random tree to the leaf node corresponding to the data to be encrypted according to the user key and the ciphertext of the data to be encrypted, and decrypting the ciphertext of the data to be encrypted; The decrypted data to be encrypted is converted into a plaintext string after the padding value is eliminated.

The above is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Claim

A data encryption method, the method comprising:

The method according to claim 1, wherein the path of generating the root node from the random number to the leaf node corresponding to the data to be encrypted according to the user key and the data to be encrypted is specifically:

The method according to claim 1, wherein the ciphertext for forming the data to be encrypted comprises: selecting a random number in the range of the interval to which the leaf node belongs: When the data to be encrypted is located in the last layer of the random number, within the range of the sub-node where the data to be encrypted is located, a random number is selected to form the ciphertext of the data to be encrypted.

A method for decrypting data, characterized in that the method comprises:

Obtaining a user key and data to be decrypted;

The method according to claim 4, wherein the recovering the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key and the data to be decrypted Specifically:

6. A data encryption device, the device comprising:

The data encryption device according to claim 6, wherein the step of performing, in the encrypting unit, generating, according to the user key and the data to be encrypted, a root node corresponding to the data to be encrypted The path of the leaf node is specifically:

a first dividing unit, configured to divide the each of the range of values into the number of divided segments, and generate a random number by using a seed of the random tree, where the random number is used to generate a spacing domain, where each interval domain is Dividing the number of copies and the selected child nodes, and making the total length of the divided interval fields equal to the length of the interval before the segmentation;

a second determining unit, configured to determine a node location of the encrypted data, where a minimum value of the node location is a sum of three values, where the three values are respectively a minimum value of a random tree above the node location, a sum of value range values to the node position, a sum of interval field interval values to the node position; a first determining unit, configured to determine whether the node position is the selected child node, and if yes, The maximum value of the node position is the sum of three values, the three values are respectively the minimum value of the node position, the value range interval value of the node position, and the value of the interval field at the node position ; If not, the maximum value of the node position is the sum of two values, the two values being the minimum value of the node position and the value interval value of the node position.

The device according to claim 6, wherein the encrypting unit performs a step and selects a random number in a range of values to which the leaf node belongs to form a secret in the ciphertext of the data to be encrypted. The text includes:

9. A device for decrypting data, characterized in that the device comprises:

An obtaining unit, configured to acquire a user key and data to be decrypted;

a decrypting unit, configured to recover the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key and the data to be decrypted, and decrypt the data to be decrypted; a conversion unit, configured to convert the decrypted data into a plaintext string after removing the padding value.

The device according to claim 9, wherein the performing step in the decrypting unit recovers the path from the root node of the random tree to the leaf node corresponding to the data to be decrypted according to the user key. For:

a second dividing unit, configured to divide the to-divided interval into equal intervals, and generate a random number by using a seed of the random tree, where the random number is used to generate each interval interval to be divided, Deriving the number of partitions of the interval domain and the selected child nodes, and making the total length of the partitioned partitions equal to the length of the interval domain before the segmentation;

a calculating unit, configured to calculate, according to the location where the ciphertext is located, a US standard information exchange standard code of the current node, and generate a seed of the random tree according to the user key and the US standard information exchange standard code of the current node; The third dividing unit is configured to generate a random number according to the seed of the random number, and divide, by the random number, the to-divided interval in which the number of nodes is located into two regional values, where the two regional values are the next random tree The total value of the field and the total interval field value of the next random tree;

a fourth determining unit, configured to determine a node location of the data to be decrypted, where a minimum value of the node location is a sum of three values, where the three values are minimum values of a random tree above the node location The sum of the value range values of the node locations, the sum of the interval field values to the node locations; the third determining unit, configured to determine whether the node locations are the selected child nodes, and if so, The maximum value of the node location is the sum of three values, the three values are respectively the minimum value of the node location, the value interval value of the node location, and the interval domain is at the node location. Value