CN101320409A - Database encryption method based on Chinese remainder theorem - Google Patents

Abstract

A database encryption method based on Chinese residue theorem is provided, which comprises the following procedures: (1) Designating and storing a global key in the system table of the database; (2) Formulating and storing a table key and a key for each field in the system table of the database; (3) Generating a random record key for each piece of record in storing the data and completing the encrypted storage of data by combining the global key, the table key and the field key as well as transferring the encryption algorithm. Therefore, the invention provides a database encryption method that is based on Chinese residue theorem and can effectively enhance the deciphering efficiency.

Description

Database encryption method based on Chinese remainder theorem

Technical field

The present invention relates to a kind of database encryption method.

Background technology

Current information society, each enterprise, government organs and military service all extensively adopt database application system to store various data and data.Quite a few is arranged in these data is confidential information, these confidential datas are if store easily by opponent's unauthorized theft with form expressly, thereby enterprise is caused enormous economic loss, and the loss that confidential information is leaked for government, military service will be catastrophic.Therefore be necessary these confidential datas are taked necessary safeguard measure, even if the opponent steals the definite implication that these data also can't be known these data.

Usually can adopt technology such as fire wall, intrusion detection and authentication on different levels, to come the safety of protected data storage in the database application system.Yet for experienced hacker, these safeguard measures of Gonna breakthrough are not to be difficult to; Can not avoid directly stealing the data leak that data storage medium brings in addition.Data are encrypted the best method that storage is the protection confidential data.

Existing database encryption technology mainly contains based on the encryption of file and based on the encryption two big classes of data item.But this two class is encrypted and is all come with some shortcomings.Based on the data base encryption of file be database file as a complete unit, utilize encryption key and corresponding cryptographic algorithm to encrypt, thus the integrality of protected data and confidentiality.But adopt this method no matter database manipulations such as modification or increase, deletion all must be encrypted entire database deciphering earlier again, greatly increased on time and the space expense.Therefore, abandoned substantially based on file ground database encryption technology in actual use.And meet the characteristic of database based on the encryption of data item, relatively be fit to the data base encryption operation.But owing under the sizable situation of data volume in the database, each data item content is all moved a cryptographic algorithm (for example traditional DES algorithm), performance loss is in time well imagined; This in addition method is generally each data item and will specifies different keys in order to make the assurance secret key safety, and data volume is big more just to mean that the quantity of key is big more, and this has also brought great difficulty to key management.

The data base encryption scheme can be divided into two kinds again from technology realizes: the one, realize encryption function in the database core, and this method fulfillment database is more up hill and dale encrypted and checking, and efficient is also higher, but a certain Database Systems of must combining closely.Another kind method is to have expanded the encryption and decryption functional layer outside the database core, and the user can use the database that has encryption function by this functional layer, and this implementation can make the different Database Systems of product support.

Summary of the invention

The invention provides a kind of database encryption method based on Chinese remainder theorem that can effectively improve encryption and decryption efficient.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of database encryption method based on Chinese remainder theorem, described database encryption method may further comprise the steps:

(1), the specified database global secret, and be saved in system's table of database;

(2), named list key and each field key, and be saved in system's table of database;

(3), for each bar record produces a record key at random, and binding data storehouse global secret, table key and field key call cryptographic algorithm and finish the encryption of data and store during data in storage, the processing procedure of cryptographic algorithm comprises:

(3.1), dynamically produce data item key: K by key generator _Ij=g (DBK, TK, R _i, F _j), wherein DBK is the database global secret, TK is table key, R _iBe i record key, F _jBe j field key; G is an one-way function on the cryptography, and it is defined as: $g(\mathrm{DBK},\mathrm{TK},R_i,F_j)=\mathrm{MD}5(\mathrm{DBK}\⊕\mathrm{TK}\⊕R_i\⊕F_j),$ MD5 is meant the MD5 algorithm in the cryptography,

Expression step-by-step XOR;

(3.2), generate one group of positive integer (d of prime number each other in twos at random ₁, d ₂, d ₃... d _i... d _n), 1≤i≤n calculates $D=\underset{i=1}{\overset{n}{\mathrm{\Π}}}{d}_i,D_i=d/d_i,$ ∏ represents product calculation, and chooses Y _iSatisfy D _iY _i=1 (mod d _i), mod represents modulo operation; Make e _i=D _iY _i(1≤i≤n), with (e ₁, e ₂, e ₃... e _i... e _n) as the real encryption key of record, and (d ₁, d ₂, d ₃... d _i... d _n) be real decruption key;

(3.3), carry out the encryption formula: $C=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{e}_j(F_{\mathrm{ij}}\⊕K_{\mathrm{ij}})\left(\mathrm{mod}D\right),$ F wherein _IjBe plaintext value, C is the ciphertext value, and ∑ is represented summation operation;

(4), during reading of data, read key, call decipherment algorithm and finish the reading of data process, the processing procedure of decipherment algorithm is from system's table of database:

(4.1), the cipher key calculation K that reads according to system's table _Ij, computation process is with (3.1)

(4.2), carry out the deciphering formula: $F_{\mathrm{ij}}=C\left(\mathrm{mod}{d}_i\right)\⊕K_{\mathrm{ij}}(1\≤i\≤n).$

Adopt (separating) close pattern of transparent adding, outside the database core, increase an encryption and decryption layer in order to finish all encryption and decryption operations.

Technical conceive of the present invention is: at first, according to Chinese remainder theorem, be no longer necessary for cryptographic algorithm of each data item operation, and only need be to cryptographic algorithm of whole record operation, compare the number of times that has directly reduced the operation cryptographic algorithm with the data item cipher mode, thereby improve the time performance of encrypting; Secondly, data item is encrypted the back ciphertext and ciphertext is one to one, and this programme is encrypted the corresponding ciphertext of the whole record in back, thereby has destroyed the expressly corresponding relation between the ciphertext, has also improved safety of data to a certain extent.At last, adopt multilayer key management mode dynamically to generate the problem that key has effectively solved cipher key management difficult.

Beneficial effect of the present invention mainly shows: 1, can effectively improve encryption and decryption efficient; 2, dynamically generate the complicacy that key reduces key management.

Description of drawings

Fig. 1 is the principle schematic based on the database encryption method of Chinese remainder theorem.

Fig. 2 creates the database synoptic diagram for the user.

Fig. 3 is the enciphering and deciphering algorithm process flow diagram based on the data base encryption of Chinese remainder theorem.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

With reference to Fig. 1～Fig. 3, a kind of database encryption method based on Chinese remainder theorem, described database encryption method may further comprise the steps:

(1), the specified database global secret, and be saved in system's table of database;

(2), named list key and each field key, and be saved in system's table of database;

(3), for each bar record produces a record key at random, and binding data storehouse global secret, table key and field key call cryptographic algorithm and finish the encryption of data and store during data in storage, the processing procedure of cryptographic algorithm comprises:

(3.1), dynamically produce data item key: K by key generator _Ij=g (DBK, TK, R _i, F _j), wherein DBK is the database global secret, TK is table key, R _iBe i record key, F _jBe j field key; G is an one-way function on the cryptography, and it is defined as: $g(\mathrm{DBK},\mathrm{TK},R_i,F_j)=\mathrm{MD}5(\mathrm{DBK}\⊕\mathrm{TK}\⊕R_i\⊕F_j),$ MD5 is meant the MD5 algorithm in the cryptography,

Expression step-by-step XOR;

(3.2), generate one group of positive integer (d of prime number each other in twos at random ₁, d ₂, d ₃... d _i... d _n), 1≤i≤n calculates $D=\underset{i=1}{\overset{n}{\mathrm{\Π}}}{d}_i{D}_i=d/d_i,$ ∏ represents product calculation, and chooses Y _iSatisfy D _iY _i=1 (mod d _i), mod represents modulo operation; Make e _i=D _iY _i(1≤i≤n), with (e ₁, e ₂, e ₃... e _i... e _n) as the real encryption key of record, and (d ₁, d ₂, d ₃... d _i... d _n) be real decruption key;

(3.3), carry out the encryption formula: $C=\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{e}_j(F_{\mathrm{ij}}\⊕K_{\mathrm{ij}})\left(\mathrm{mod}D\right),$ F wherein _IjBe plaintext value, C is the ciphertext value, and ∑ is represented summation operation;

(4), during reading of data, read key, call decipherment algorithm and finish the reading of data process, the processing procedure of decipherment algorithm is from system's table of database:

(4.1), the cipher key calculation K that reads according to system's table _Ij, computation process is with (3.1)

(4.2), carry out the deciphering formula: $F_{\mathrm{ij}}=C\left(\mathrm{mod}{d}_i\right)\⊕K_{\mathrm{ij}}(1\≤i\≤n).$

Adopt (separating) close pattern of transparent adding, outside the database core, increase an encryption and decryption layer in order to finish all encryption and decryption operations.

The concrete course of work of present embodiment is:

At first, the user creates database, and acquiescence is created system's table when creating database, is used to deposit whether follow-up data encrypt and information such as encryption key; While specified database level key.

The user designs the tables of data that needs, and defines sensitivity (secret) information field in this table, and these fields will be encrypted storage in database, and other information will be stored with the plaintext form.For example: define certain enterprise staff information table, may include fields such as employee's name, sex, age, position, technical title, affiliated function, monthly pay.Monthly pay in these fields, age may be sensitive information for the employee, so just can define this two field encryption storages.Also be these two field specific field keys simultaneously.

When database adds data, determine according to encryption indicator in system's table whether this field encrypts storage, encrypt storage if desired and then call cryptographic algorithm generation ciphertext and storage according to the key in system's table.This process is transparent to the user.

Equally, also determine according to the encryption indicator in system's table whether needs are decrypted processing during data query.If query portion field information then do not need whole record is decrypted only.In above-mentioned example, if inquiry employee's name, sex, monthly pay information, according to the encryption indicator in system's table as can be known name and sex all be stored in clear, do not need decryption processing; Monthly pay is to encrypt storage, need call decipherment algorithm and be decrypted.Another encrypted fields age is not queried to does not just need to be decrypted processing.This process also is transparent concerning the user.

The disabled user walks around the encrypt data that can only obtain not having practical significance when the encryption and decryption parts are stolen data.

The computation process of enciphering and deciphering algorithm more specifically, can be described with following example.All directly use the value type data in the computation process example for describing more compactly, other categorical data can be got two bytes successively according to binary data and carry out similar calculating.

Algorithm computation process example: suppose that cryptographically a plaintext records three fields formations, their value is respectively: F ₁=5, F ₂=6, F ₃=2; Producing an ergin number at random is: d ₁=31, d ₂=37, d ₃=41; The K that key generator generates ₁=11, K ₂=22, K ₃=33, be calculated as follows so:

Preparation is calculated:

D＝d ₁*d ₂*d ₃＝47027；

D ₁＝D/d ₁＝47027/31＝1517；

D ₂＝D/d ₂＝47027/37＝1271；

D ₃＝D/d ₃＝47027/41＝1147；

Y ₁＝15；

Y ₂＝20；

Y ₃＝40；

e ₁＝D ₁*Y ₁＝22755；

e ₂＝D ₂*Y ₂＝25420；

e ₃＝D ₃*Y ₃＝45880；

Carry out and encrypt formula: $C=[{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="A20081006309800121.png"\; state="\{\{state\}\}">e</figure-callout>}}_1*({\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="A20081006309800121.png"\; state="\{\{state\}\}">F</figure-callout>}}_1\&CirclePlus;.K_1)+e_2*(F_2\&CirclePlus;K_2)+e_3*(F_3\&CirclePlus;K_3)]\mathrm{ModD}$ $(5\&CirclePlus;11)+25420*(6\&CirclePlus;22)+45880*(2\&CirclePlus;33)$

Carry out the deciphering formula:

${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="A20081006309800121.png"\; state="\{\{state\}\}">F</figure-callout>}}_1=\left(\mathrm{C\; Mod}{d}_1\right)\&CirclePlus;{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="A20081006309800121.png"\; state="\{\{state\}\}">K</figure-callout>}}_1=\left(26767\mathrm{Mod}31\right)\&CirclePlus;11=5;$

$F_2=\left(\mathrm{C\; Mod}{d}_2\right)\&CirclePlus;K_2=\left(26767\mathrm{Mod}37\right)\&CirclePlus;22=6;$

$F_3=\left(\mathrm{C\; Mod}{d}_3\right)\&CirclePlus;K_3=\left(26767\mathrm{Mod}41\right)\&CirclePlus;33=2.$

Claims (2)

1, a kind of database encryption method based on Chinese remainder theorem, it is characterized in that: this method specifically may further comprise the steps:

(1), the specified database global secret, and be saved in system's table of database;

(2), named list key and each field key, and be saved in system's table of database;

(3), for each bar record produces a record key at random, and binding data storehouse global secret, table key and field key call cryptographic algorithm and finish the encryption of data and store during data in storage, the processing procedure of cryptographic algorithm comprises:

(3.1), dynamically produce data item key: K by key generator _Ij=g (DBK, TK, R _i, F _j), wherein DBK is the database global secret, TK is table key, R _iBe i record key, F _jBe j field key; G is an one-way function on the cryptography, and it is defined as:

$g(\mathrm{DBK},\mathrm{TK},R_i,F_i)=\mathrm{MD}5(\mathrm{DBK}\&CirclePlus;\mathrm{TK}\&CirclePlus;R_i\&CirclePlus;F_i),$ MD5 is meant the MD5 algorithm in the cryptography,

Expression step-by-step XOR;

(3.2), generate one group of positive integer (d of prime number each other in twos at random ₁, d ₂, d ₃... d _i... d _n), 1≤i≤n calculates $D=\underset{i=1}{\overset{n}{\mathrm{\&Pi;}}}{d}_i,D_i=d/d_i,$ ∏ represents product calculation, and chooses Y _iSatisfy D _iY _i=1 (mod d _i), mod represents modulo operation; Make e _i=D _iY _i(1≤i≤n), with (e ₁, e ₂, e ₃... e _i... e _n) as the real encryption key of record, and (d ₁, d ₂, d ₃... d _i... d _n) be real decruption key;

(3.3), carry out the encryption formula: $C=\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{e}_j(F_{\mathrm{ij}}\&CirclePlus;K_{\mathrm{ij}})\left(\mathrm{mod}D\right),$ F wherein _IjBe plaintext value, C is the ciphertext value, and ∑ is represented summation operation;

(4), during reading of data, read key, call decipherment algorithm and finish the reading of data process, the processing procedure of decipherment algorithm is from system's table of database:

(4.1), the cipher key calculation K that reads according to system's table _Ij, computation process is with (3.1)

(4.2), carry out the deciphering formula: $F_{\mathrm{ij}}=C\left(\mathrm{mod}\underset{i}{d}\right)\&CirclePlus;K_{\mathrm{ij}}(1\&le;i\&le;n).$

2, the database encryption method based on Chinese remainder theorem as claimed in claim 1 is characterized in that: increase by one in order to finish the encryption and decryption layer of all encryption and decryption operations outside the database core.

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