CN104618092A - Information encryption method and system - Google Patents

Abstract

The present invention provides an information encryption method and system. The above method includes the following steps: according to the subkey and the right part value generated by the key generator, the first output value is obtained after operation through a preset function; the first output value is obtained by the second An XOR operation is performed between an output value and the left part value to obtain a second output value; the right part value is replaced by the left part value, the second output value is replaced by the right part value, and the above steps are repeated until the preset number of cycles , to obtain the target value of the left part and the target value of the right part; combine the target value of the left part and the target value of the right part, and output the target ciphertext; wherein, the plaintext is divided into left and right parts with equal digits in advance; the present invention uses different plaintexts to generate different The key method is used to realize the unpredictability of the real key, which greatly improves the security of its encryption algorithm, and at the same time, there will not be too much reduction in performance.

Description

An information encryption method and system

technical field

The invention belongs to the field of communication security, in particular to an information encryption method and system.

Background technique

The DES encryption algorithm is a product generated in response to the rapid development of computer science and technology. Today, with excellent computing power, the encryption strength of the DES algorithm does not meet our requirements, and it is easily cracked by exhaustive attacks. In history, the DES algorithm The cases of being cracked are not uncommon. In modern society, there are many products that replace the DES algorithm. In addition to choosing a substitute for DES, you can also choose to improve the algorithm to strengthen its encryption strength and make it less easy to be cracked. .

Limitations of the original encryption algorithm:

In the DES encryption algorithm, as long as the original key remains unchanged, the round key generated in each round will also be the same, which brings a big security hole to the attacker, and the plaintext attack method can be used to easily to obtain the encryption key.

Improvements to the existing DES algorithm:

1. One-layer DES encryption can be easily cracked, so add several more layers of encryption, such as the commonly used triple-DES encryption algorithm, although it can better resist the attack of the plaintext method, but it pays for the calculation code, and its encryption difficulty Compared with the ordinary DES encryption algorithm, it will increase by n-1 times (n is the n-fold encryption algorithm, for example, the 3-fold encryption algorithm will increase the difficulty by 2 times compared with the ordinary DES encryption algorithm).

2. Change the subkey used in each round of transformation, so that the generation of the subkey is not only related to the initial key, but also related to the plaintext. Its implementation is based on the ordinary DES algorithm, at the step of generating the subkey, change the subkey generation function, and perform correlation operations between the original generated subkey and the plaintext generated in the previous round, so that the subkey becomes Unpredictable, this will effectively resist the plaintext attack method, and the method of guessing the key becomes impossible. Its disadvantages are also obvious. Since each round transformation will regenerate a subkey, its computational complexity will increase.

Contents of the invention

The present invention provides an information encryption method and system to solve the above problems.

The present invention provides a kind of information encryption method, and above-mentioned method comprises the following steps:

According to the sub-key and the right part value generated by the key generator, the first output value is obtained after the operation is performed through the preset function;

performing an XOR operation on the first output value and the left partial value to obtain a second output value;

replacing the left partial value with the right partial value, replacing the right partial value with the second output value, and repeating the above steps until the preset number of cycles to obtain the left partial target value and the right partial target value;

Combining the target value of the left part and the target value of the right part, the target ciphertext is output; wherein, the plaintext is divided into two parts with the same number of digits in advance.

The present invention also provides an information encryption system, including a division module, a first output value module, a second output value module, a target part acquisition module, and a target ciphertext output module;

Wherein, the division module is connected to the second output value module through the first output value module; the first output value module is connected to the target part acquisition module through the second output value module; The second output value module is connected to the target ciphertext output module through the target part acquisition module; the division module is also connected to the target part acquisition module;

The division module is used to divide the plaintext into left and right parts with equal number of digits in advance and notify the first output value module and the target part acquisition module of the division result

The first output value module is configured to obtain a first output value after performing operations through a preset function according to the subkey and the right part value generated by the key generator, and send the first output value to the the second output value module;

The second output value module is configured to perform an XOR operation on the first output value and the left partial value to obtain a second output value;

The target part acquisition module is used to replace the right part value with the left part value, replace the second output value with the right part value, repeat the above steps until the preset number of cycles, and obtain the left part target value and the right part target value and send the left part target value and the right part target value to the target ciphertext output module;

The target ciphertext output module is used to combine the left part of the target value and the right part of the target value to output the target ciphertext.

Compared with the previous technology, the information encryption method and system provided by the present invention adopts the method of generating different keys from different plaintexts to realize the unpredictability of the real key, which greatly improves the security of the encryption algorithm. At the same time, In terms of performance, there will not be much degradation.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 shows the flow chart of the information encryption method of Embodiment 1 of the present invention;

Fig. 2 shows the flow chart of the information encryption method of Embodiment 2 of the present invention;

FIG. 3 is a structural diagram of an information encryption system according to Embodiment 3 of the present invention.

Detailed ways

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

The DES encryption algorithm is a symmetric encryption algorithm developed by IBM. It is a 16-round Feis tel structure cipher. Its block length is 64bits, and the key length is also 64bits. parity.

Fig. 1 shows the flow chart of the information encryption method of embodiment 1 of the present invention, comprises the following steps:

Step 101: pre-dividing the plaintext into left and right parts with equal number of digits;

Step 102: According to the sub-key and the right partial value generated by the key generator, the first output value is obtained after operation through the preset function;

Step 103: performing XOR operation on the first output value and the left partial value to obtain a second output value;

Step 104: replace the left part value with the right part value, replace the right part value with the second output value, repeat the above steps: 202-204, until the preset number of cycles, and obtain the left part target value and the right part target value ;

Step 105: Combine the left part of the target value and the right part of the target value, and output the target ciphertext.

Fig. 2 shows the flow chart of the information encryption method of embodiment 2 of the present invention, comprises the following steps:

Step 201: Divide the plaintext into left and right parts, the value of the left part is L0, and the value of the right part is R0, wherein the number of digits in L0 is the same as that in R0.

For example: Divide the 64bits of the plaintext into left and right parts, L0 and R0 respectively, where the number of digits in L0 and R0 are both 32bits.

This is to disrupt the ordering of plaintext groups, which is equivalent to an initial simple encryption process.

Step 202: After performing the f function operation on the R0 and the subkey k1 generated by the key generator, f(R0, k1) is obtained;

Step 203: XOR operation is performed on the f(R0, k1) and the L0 to obtain

Step 204: Record the R0 as L1 to replace the left partial value, and at the same time write Record it as R1 to replace the right partial value, thus completing the first round of iterative operation;

Step 205: Repeat steps 102-105 until the cycle is repeated 16 times to obtain the target value of the left part R16 and the target value of the right part L16;

Step 206: Combining the obtained R16 and L16 packets, sorting and encrypting them, and outputting the target ciphertext.

Fig. 3 shows the structure diagram of the information encryption system according to Embodiment 3 of the present invention, including a division module, a first output value module, a second output value module, a target part acquisition module, and a target ciphertext output module;

Wherein, the division module is connected to the second output value module through the first output value module; the first output value module is connected to the target part acquisition module through the second output value module; The second output value module is connected to the target ciphertext output module through the target part acquisition module; the division module is also connected to the target part acquisition module;

The division module is used to divide the plaintext into left and right parts with equal number of digits in advance and notify the first output value module and the target part acquisition module of the division result

The first output value module is configured to obtain a first output value after performing operations through a preset function according to the subkey and the right part value generated by the key generator, and send the first output value to the the second output value module;

The second output value module is configured to perform an XOR operation on the first output value and the left partial value to obtain a second output value;

The target part acquisition module is used to replace the right part value with the left part value, replace the second output value with the right part value, repeat the above steps until the preset number of cycles, and obtain the left part target value and the right part target value and send the left part target value and the right part target value to the target ciphertext output module;

The target ciphertext output module is used to combine the left part of the target value and the right part of the target value to output the target ciphertext.

Compared with the previous technology, the information encryption method and system provided by the present invention adopts the method of generating different keys from different plaintexts to realize the unpredictability of the real key, which greatly improves the security of the encryption algorithm. At the same time, In terms of performance, there will not be much degradation.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. an information ciphering method, is characterized in that, comprises the following steps:

The sub-key generated according to key generator and right part score value, after carrying out computing, obtain the first output valve by preset function;

Described first output valve and left part score value are carried out XOR, obtains the second output valve;

Described right part score value is replaced left part score value, described second output valve is replaced right part score value, repeats above-mentioned steps, until preset loop number of times, obtain left half desired value and right half desired value;

Combination left half desired value and right half desired value, export target ciphertext; Wherein, expressly the equal left and right two parts of figure place will be divided in advance.

2. method according to claim 1, is characterized in that, if left part score value is L0, right part score value is R0, and the sub-key that key generator generates is k1, and preset function is f function, then the first output valve is f (R0, k1).

3. method according to claim 2, is characterized in that, described first output valve and left part score value are carried out XOR, and the second output valve process that obtains is:

Described f (R0, k1) is carried out XOR with described L0, and obtaining the second output valve is

4. method according to claim 3, is characterized in that, described right part score value is replaced left part score value, by the process that described second output valve replaces right part score value is:

Described R0 is designated as L1 and replaces left part score value, simultaneously handle be designated as R1 and replace right part score value.

5. method according to claim 1, is characterized in that, preset loop number of times is 16.

6. method according to claim 1, is characterized in that, combination left half desired value and right half desired value, and the process exporting target ciphertext is:

Line ordering of the left half desired value of acquisition and the combination of right half desired value being gone forward side by side is encrypted, and exports target ciphertext.

7. an information encryption system, is characterized in that, comprises and divides module, the first output valve module, the second output valve module, target part acquisition module, target ciphertext output module;

Wherein, described division module is connected with described second output valve module by described first output valve module; Described first output valve module is connected with described target part acquisition module by described second output valve module; Described second output valve module is connected with described target ciphertext output module by described target part acquisition module; Described division module is also connected with described target part acquisition module;

Described division module, for will being expressly divided into the equal left and right two parts of figure place and division result being notified described first output valve module, described target part acquisition module in advance

Described first output valve module, for the sub-key that generates according to key generator and right part score value, after carrying out computing, obtains the first output valve and described first output valve is sent to described second output valve module by preset function;

Described second output valve module, for described first output valve and left part score value are carried out XOR, obtains the second output valve;

Described target part acquisition module, for described right part score value is replaced left part score value, described second output valve is replaced right part score value, repeat above-mentioned steps, until preset loop number of times, obtain left half desired value and right half desired value and described left half desired value and right half desired value are sent to described target ciphertext output module;

Described target ciphertext output module, for combining left half desired value and right half desired value, exports target ciphertext.