CN100591007C - Encryption and decryption method - Google Patents

Abstract

An encryption method. First, a plurality of soldier blocks are selected from a plurality of data blocks constituting data. A plurality of data blocks are selected from the remaining data blocks. And then, encrypting a first data block in the selected data blocks according to at least one of the soldier blocks to obtain a first ciphertext, and encrypting a second data block in the selected data blocks according to at least one of the soldier blocks to obtain a second ciphertext. The generated ciphertext may be used as a pioneer block in an encryption process for a subsequent data block.

Description

Encryption and Decryption Methods

technical field

The present invention relates to an encryption and decryption method, and in particular to a method for encrypting and decrypting by utilizing the content of data itself.

Background technique

In cryptography, most of them adopt symmetric (Symmetric) or asymmetric (Asymmetric) encryption/decryption mechanism. For example, symmetric encryption/decryption algorithms include RC4, DES and AES algorithms. In the symmetric encryption/decryption algorithm, the same key (Key) is used when encrypting data and decrypting data. Asymmetric encryption/decryption algorithms include the RSA algorithm. In the asymmetric encryption/decryption algorithm, different keys (public key and private key) are used to encrypt data and decrypt data. For symmetric and asymmetric encryption/decryption algorithms, how to transfer the key will form an important security consideration. Although the asymmetric encryption/decryption algorithm has better security than the symmetric encryption/decryption algorithm, its relative complexity is also increased.

In some encryption/decryption algorithms, such as the substitution (Substitution) encryption/decryption algorithm, a key may not be used when encrypting data and decrypting data. Figure 1 shows a schematic diagram of an alternative encryption/decryption algorithm. As shown in Figure 1, in the ciphertext generated according to the encryption/decryption algorithm, one letter will be replaced by another letter. For example, A is replaced by V, B by G, C by S, D by Q, etc. For alternative encryption/decryption algorithms, the ciphertext is very easy to break through frequent analysis, which has low security.

Contents of the invention

In view of this, the present invention provides encryption and decryption methods.

The encryption method of the embodiment of the present invention. First, divide the data to generate multiple data blocks. A plurality of first data blocks are selected among the plurality of data blocks constituting the data. A second data block is selected from the remaining data blocks. Afterwards, at least one of the first data blocks is selected. Encrypt the second data block according to the selected first data block, so as to obtain the first ciphertext.

The decryption method of the embodiment of the present invention. Firstly, the first data block is selected from the plurality of data blocks constituting the data. A second data block is selected from the remaining data blocks. Afterwards, the second data block is decrypted according to the first data block, so as to obtain the first plaintext.

In some embodiments, the generated ciphertext can be used as a spearhead block in the encryption procedure of subsequent data blocks.

The above-mentioned method of the present invention can be recorded in a physical medium by way of program code. When the program code is loaded and executed by the machine, the machine becomes a device for implementing the present invention.

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, the following specific examples will be described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram showing an alternative encryption/decryption algorithm.

FIG. 2 is a flowchart showing an encryption method according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a decryption method according to an embodiment of the present invention.

FIG. 4A shows an example of encryption where the number of spike blocks is 1 and the encryption of the data block is an XOR operation performed on the data block.

FIG. 4B shows an example of decryption of the ciphertext in which the number of the pioneer block in FIG. 4A is 1 and the encryption of the data block is an XOR operation performed on the data block.

FIG. 5A shows an example of encryption where the number of vanguard blocks is 2 and the encryption of the data block is an XOR operation performed on the data block.

FIG. 5B shows an example of decryption of the ciphertext in which the number of pioneer blocks in FIG. 5A is 2 and the encryption of the data block is an XOR operation performed on the data block.

[Description of main component labels]

S210, S220, ..., S280～operation steps;

S310, S320, ..., S380～operation steps.

Detailed ways

Fig. 2 shows an encryption method according to an embodiment of the present invention. In this embodiment, the data can be encrypted according to its content.

In step S210, the data is divided into multiple data blocks. It should be noted that each data block can have the same length, such as 1 bit (Bit), 1 byte (Byte), or other sizes. In some embodiments, each data block may also have a different length. In step S220, one or more data blocks are selected from the data blocks as Sentry blocks. Note that the vanguard block is used as a key for encryption of other data blocks. In some embodiments, the vanguard block may be the same as the original data block, or the original data block may be processed in advance. For example, perform logical operations on data blocks, such as XOR, AND, OR, and NOT, or based on encryption/decryption algorithms, such as replacement encryption/decryption algorithms, symmetric encryption/decryption algorithms, or asymmetric encryption/decryption algorithms Algorithms encrypt data blocks.

In step S230, at least one data block is selected from the remaining data blocks. In step S240, at least one of the pioneer blocks is selected, and in step S250, the selected data block is encrypted according to the selected pioneer block, so as to obtain ciphertext. It is worth noting that the encryption of the data block can be based on the logical operation of the data block based on the pioneer block, or based on the encryption/decryption algorithm, such as the replacement encryption/decryption algorithm, the symmetric encryption/decryption algorithm, or the asymmetric encryption/decryption algorithm. The decryption algorithm encrypts the data block.

In step S260, it is determined whether the encryption operation of the corresponding data is finished. It should be noted that, in some embodiments, when all the data blocks of the data are selected, the encryption operation of the corresponding data ends. In some embodiments, when a predetermined number of data blocks in the data are selected, the encryption operation of the corresponding data ends. If the encryption operation of the corresponding data is completed (Yes in step S260), the process ends. If the encryption operation of the corresponding data has not been completed (No in step S260), as in step S270, it is judged whether the ciphertext generated in step S250 must be set as a pioneer block. It must be noted that the ciphertext can choose whether to be used as a pioneer block in the encryption program of the subsequent data block, so as to increase the type and complexity of the encryption program. If the generated ciphertext does not need to be set as a pioneer block (No in step S270), the process returns to step S230, and at least one data block is selected again from the remaining data blocks that have not been selected to perform the encryption process. If the generated ciphertext needs to be set as a pioneer block (yes in step S270), as in step S280, the ciphertext is set as a pioneer block, and the process returns to step S230, and is selected from the remaining data blocks that have not yet been selected. At least one data block is used for encryption procedure.

It must be reminded that in the encryption program, the selection and sequence of the leading block, the sequence of data block selection and related information will be recorded to provide data decryption reference.

Fig. 3 shows a decryption method according to an embodiment of the present invention. In this embodiment, the data can be decrypted according to its own content.

In step S310, the data is divided into multiple data blocks. It should be noted that each data block can have the same length, such as 1 bit, 1 byte, or other sizes. In some embodiments, each data block may also have a different length. In step S320, one or more data blocks are selected from the data blocks as the vanguard blocks. Note that the vanguard block is used as the key for decrypting other data blocks. In some embodiments, the vanguard block may be the same as the original data block, or the original data block may be processed in advance. For example, perform logical operations on data blocks, such as XOR, AND, OR, and NOT, or based on encryption/decryption algorithms, such as replacement encryption/decryption algorithms, symmetric encryption/decryption algorithms, or asymmetric encryption/decryption algorithms Algorithms encrypt data blocks.

In step S330, at least one data block is selected from the remaining data blocks. In step S340, at least one of the vanguard blocks is selected, and in step S350, the selected data block is decrypted according to the selected vanguard block, so as to obtain a plaintext. It is worth noting that the decryption of the data block can be based on the logical operation of the data block based on the pioneer block, or based on the encryption/decryption algorithm, such as the replacement encryption/decryption algorithm, the symmetric encryption/decryption algorithm, or the asymmetric encryption/decryption algorithm. The decryption algorithm decrypts the data block.

In step S360, it is determined whether the decryption operation of the corresponding data is finished. It should be noted that, in some embodiments, when all the data blocks of the data are selected, the decryption operation of the corresponding data ends. In some embodiments, when a predetermined number of data blocks in the data are selected, the decryption operation of the corresponding data ends. If the decryption operation of the corresponding data is completed (Yes in step S360), the process ends. If the decryption operation of the corresponding data has not been completed (No in step S360), as in step S370, it is judged whether the plaintext generated in step S350 should be set as a pioneer block. If the generated plaintext does not need to be set as a pioneer block (No in step S370), the process returns to step S330, and at least one data block is selected again from the remaining data blocks that have not been selected to perform the decryption process. If the generated plaintext needs to be set as a pioneer block (yes in step S370), as in step S380, the plaintext is set as a pioneer block, and the process returns to step S330, and at least one is selected from the remaining data blocks that have not yet been selected. Data block for decryption procedure.

Next, an example is presented for illustration.

密文Y2被设为尖兵区块。之后，数据区块X3被选择，且依据尖兵区块Y2加密为密文

密文Y3被设为尖兵区块。上述程序重复，直至数据区块Xn被选择，且依据尖兵区块Yn-1加密为密文

图4B显示图4A中尖兵区块的数目为1且数据区块的加密是对于数据区块进行XOR运算的密文的解密例子。如图4B所示，其中密文的数据区块为Y1、Y2、Y3、...、Yn，平文的数据区块为X1、X2、X3、...、Xn。在此例子中，Y1被选定为尖兵区块，且尖兵区块与原始数据区块的内容相同，因此X1＝Y1。接着，数据区块Y2被选择，且依据尖兵区块X1解密为平文

平文X2被设为尖兵区块。之后，数据区块Y3被选择，且依据尖兵区块X2解密为平文平文X3被设为尖兵区块。上述程序重复，直至数据区块Yn被选择，且依据尖兵区块Xn-1解密为平文

FIG. 4A shows an example of encryption where the number of spike blocks is 1 and the encryption of the data block is an XOR operation performed on the data block. As shown in FIG. 4A , the plaintext data blocks are X1, X2, X3, . . . , Xn, and the ciphertext data blocks are Y1, Y2, Y3, . . . , Yn. In this example, X1 is selected as the vanguard block, and the content of the vanguard block is the same as that of the original data block, so Y1=X1. Next, the data block X2 is selected and encrypted into ciphertext according to the pioneer block Y1

The ciphertext Y2 is set as the vanguard block. After that, the data block X3 is selected and encrypted into ciphertext according to the pioneer block Y2

Ciphertext Y3 is set as the vanguard block. The above procedure is repeated until the data block Xn is selected and encrypted into ciphertext according to the pioneer block Yn-1

FIG. 4B shows an example of decryption of the ciphertext in which the number of the pioneer block in FIG. 4A is 1 and the encryption of the data block is an XOR operation performed on the data block. As shown in FIG. 4B , the data blocks of the ciphertext are Y1, Y2, Y3, . . . , Yn, and the data blocks of the plaintext are X1, X2, X3, . . . , Xn. In this example, Y1 is selected as the vanguard block, and the content of the vanguard block is the same as that of the original data block, so X1=Y1. Next, the data block Y2 is selected and decrypted into plain text according to the pioneer block X1

Pingwen X2 is set as the vanguard block. After that, the data block Y3 is selected and decrypted into plaintext according to the pioneer block X2 Pingwen X3 is set as the vanguard block. The above procedure is repeated until the data block Yn is selected and decrypted into plain text according to the pioneer block Xn-1

密文Y2被设为尖兵区块。另一方面，数据区块Xn-1被选择，且依据尖兵区块Yn加密为密文

密文Yn-1被设为尖兵区块。上述程序重复，直至所有平文数据区块被选择且加密。图5B显示图5A中尖兵区块的数目为2且数据区块的加密是对于数据区块进行XOR运算的密文的解密例子。如图5B所示，其中密文的数据区块为Y1、Y2、Y3、...、Yn，平文的数据区块为X1、X2、X3、...、Xn。在此例子中，Y1与Yn同时被选为定为尖兵区块，且尖兵区块与原始数据区块的内容相同，因此X1＝Y1且Xn＝Yn。类似地，相应数据的解密作业可以分别由两端展开。数据区块Y2被选择，且依据尖兵区块X1解密为平文平文X2被设为尖兵区块。另一方面，数据区块Yn-1被选择，且依据尖兵区块Xn解密为平文

平文Xn-1被设为尖兵区块。上述程序重复，直至所有密文数据区块被选择且解密。FIG. 5A shows an example of encryption where the number of vanguard blocks is 2 and the encryption of the data block is an XOR operation performed on the data block. As shown in FIG. 5A , the plaintext data blocks are X1, X2, X3, . . . , Xn, and the ciphertext data blocks are Y1, Y2, Y3, . . . , Yn. In this example, X1 and Xn are selected as the pioneer block at the same time, and the contents of the pioneer block and the original data block are the same, so Y1=X1 and Yn=Xn. It is worth noting that the encryption operation of the corresponding data can be carried out by both ends. The data block X2 is selected and encrypted into ciphertext according to the pioneer block Y1

The ciphertext Y2 is set as the vanguard block. On the other hand, the data block Xn-1 is selected and encrypted into ciphertext according to the pioneer block Yn

The ciphertext Yn-1 is set as the vanguard block. The above procedure is repeated until all plaintext data blocks are selected and encrypted. FIG. 5B shows an example of decryption of the ciphertext in which the number of pioneer blocks in FIG. 5A is 2 and the encryption of the data block is an XOR operation performed on the data block. As shown in FIG. 5B , the data blocks of the ciphertext are Y1, Y2, Y3, . . . , Yn, and the data blocks of the plaintext are X1, X2, X3, . . . , Xn. In this example, Y1 and Yn are selected as the pioneer block at the same time, and the contents of the pioneer block and the original data block are the same, so X1=Y1 and Xn=Yn. Similarly, the decryption operation of the corresponding data can be carried out by both ends respectively. The data block Y2 is selected and decrypted into plain text according to the pioneer block X1 Pingwen X2 is set as the vanguard block. On the other hand, the data block Yn-1 is selected and decrypted into plaintext according to the pioneer block Xn

Plain text Xn-1 is set as the vanguard block. The above procedure is repeated until all ciphertext data blocks are selected and decrypted.

The method of the present invention, or a specific form or part thereof, may be contained in a physical medium in the form of program code, such as a floppy disk, an optical disk, a hard disk, or any other machine-readable (such as computer-readable) storage medium , wherein, when the program code is loaded and executed by a machine, such as a computer, the machine becomes a device for implementing the present invention. The method and device of the present invention can also be transmitted in the form of program code through some transmission media, such as wires or cables, optical fibers, or any transmission mode, wherein when the program code is received, loaded and executed by a machine, such as a computer , this machine becomes the apparatus for realizing the present invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique device that operates similarly to application-specific logic circuits.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall prevail as defined by the appended claims.

Claims (10)

1. An encryption method comprising the following steps: Split data to generate multiple data blocks; selecting a plurality of first data blocks from the plurality of data blocks; selecting a second data block from the remaining plurality of data blocks; selecting at least one of the plurality of first data blocks; and Encrypting the second data block according to the selected first data block to obtain a first ciphertext, In the encryption process, the selection and sequence of the first data block, the sequence of data block selection and related information will be recorded to provide data decryption reference. 2. The encryption method according to claim 1, further comprising the following steps: selecting a third data block from the remaining plurality of data blocks; and Encrypt the third data block according to the first ciphertext to obtain a second ciphertext. 3. The encryption method according to claim 1, further comprising performing a logical operation on the first data block before encrypting the second data block. 4. The encryption method according to claim 1, further comprising encrypting the first data block according to an encryption/decryption algorithm before encrypting the second data block. 5. The encryption method according to claim 1, wherein encrypting the second data block according to the first data block is performing a logic operation on the second data block. 6. The encryption method according to claim 1, wherein encrypting the second data block according to the first data block is encrypting the second data block according to an encryption/decryption algorithm. 7. A decryption method corresponding to the encryption method of claim 1, comprising the following steps: selecting a first data block among a plurality of data blocks constituting the data; selecting a second data block from the remaining plurality of data blocks; and Decrypt the second data block according to the first data block, so as to obtain the first plaintext. 8. The decryption method according to claim 7, further comprising the steps of: selecting a third data block from the remaining plurality of data blocks; and Decrypt the third data block according to the first plaintext to obtain a second plaintext. 9. The decryption method according to claim 7, further comprising performing a logical operation on the first data block before decrypting the second data block. 10. The decryption method according to claim 7, further comprising decrypting the first data block according to an encryption/decryption algorithm before decrypting the second data block.

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