Author

# Liu Botao

Bio: Liu Botao is an academic researcher. The author has contributed to research in topics: Block cipher & Key (cryptography). The author has an hindex of 1, co-authored 6 publications receiving 6 citations.

Topics: Block cipher, Key (cryptography), Encryption, Cryptography, Cipher

##### Papers

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21 Sep 2016

TL;DR: In this article, a lightweight SFN block cipher implementation method was proposed, where the last 32 digits of an original secret key serve as control signals, so as to control the selection of one of the two algorithm structures for enciphering/deciphering, and the other structure for secret key extension.

Abstract: The invention discloses a novel and highly secure lightweight SFN block cipher implementation method. The method has the benefits that a novel cipher mode is designed and comprises two typical block cipher structures, i.e., the SP network structure and the Feistel network structure; the last 32 digits of an original secret key serve as control signals, so as to control the selection of one of the two algorithm structures for enciphering/deciphering, and the selection of the other structure for secret key extension; in the algorithm, one cipher structure can be used for both enciphering/deciphering operation and secret key extension operation, and 2 different operation modes are achieved; compared with the method in which a fixed cipher structure is used for enciphering/deciphering and secret key extension iterative operations, the novel and highly safe lightweight SFN block cipher implementation method can improve the defense difficulty coefficient by 2 times for some attack methods, so as to meet multi-level security demands of various users; the SFN algorithm has the advantages of high flexibility, high extensibility, high security and low resources, so as to achieve better application prospects.

5 citations

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13 Dec 2019

TL;DR: In this article, a lightweight block cipher algorithm Shadow implementation method and device based on an SPN structure and a computer readable medium is presented, which comprises the following steps: obtaining a 64-bit plaintext to be encrypted, and determining an iteration round number R according to the number of key bits.

Abstract: The invention discloses a lightweight block cipher algorithm Shadow implementation method and device based on an SPN structure and a computer readable medium. The method comprises the following steps:obtaining a 64-bit plaintext to be encrypted, and determining an iteration round number R according to the number of key bits; in the first round of operation to the Rth round of operation, enablingeach round of operation to be sequentially subjected to round key addition operation, nonlinear S-box replacement operation, row displacement operation and linear column hybrid operation, and updatinga key; taking the data obtained after the linear column hybrid operation as the to-be-encrypted data of the next round of operation, and taking the updated key as the key of the next round of operation; and performing round key addition operation on the data after the Rth round of operation and the key, and outputting a ciphertext. On the basis that part of cryptographic indexes of the S box arenot affected by affine transformation, a composite affine mathematical method is adopted, the pseudo-random key related S box is constructed on a finite field GF (24), meanwhile, a column hybrid matrix is constructed according to the Schmidt matrix orthogonalization principle, and attacks can be effectively resisted.

1 citations

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09 Jun 2020

TL;DR: In this paper, a method and a device for realizing a Shield block cipher generated by a novel secret key, and a readable storage medium was presented, where the Shield grouping length is designed to be 128 bits, a secret key is any length, an encryption round function is based on an SPN structure, and the encryption sequence is round secret key addition, S box replacement, row shifting and column hybrid transformation in sequence.

Abstract: The invention discloses a method and a device for realizing a Shield block cipher generated by a novel secret key, and a readable storage medium. According to the method, the Shield grouping length isdesigned to be 128 bits, a secret key is any length, an encryption round function is based on an SPN structure, and the encryption sequence is round secret key addition, S box replacement, row shifting and column hybrid transformation in sequence. The secret key expansion function divides an original secret key into three parts, generates three round secret keys by using a hash function MD5, anduses the round secret keys in different rounds of addition operation. According to the S box replacement transformation, 128-bit data replacement transformation is carried out by adopting two 4 * 4 Sboxes; the data are divided into 32 4-bit units; and along with the change of encryption/decryption rounds, the data units respectively carry out corresponding S box increasing/decreasing replacementoperation. According to the invention, the occupied area resource of the Shield cipher is small; the storage space for storing the original secret key is reduced; and the known attack can be well resisted by increasing the length of the secret key and expanding the secret key space.

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19 Jun 2020

TL;DR: In this paper, a novel high-security lightweight ECEG block cipher implementation method and system and a storage medium was proposed, key expansion is carried out based on an NP difficult problem of elliptic curve discrete logarithm, and the expansion enables a password attacker to be difficult to infer what an original key is even if the password attacker obtains a key of an intermediate round, so the security of the password is further improved.

Abstract: The invention provides a novel high-security lightweight ECEG block cipher implementation method and system and a storage medium. Key expansion is carried out based on an NP difficult problem of elliptic curve discrete logarithm, and the expansion enables a password attacker to be difficult to infer what an original key is even if the password attacker obtains a key of an intermediate round, so the security of the password is further improved, and the ECDLP is applied to the field of encryption and decryption of the block password for the first time; besides, the technical scheme of the invention further provides an extended generalized Feistel structure, which is different from a conventional Feistel structure, an MDS matrix is generated after four times of iteration, the MDS matrix mainly plays a diffusion role in the whole cryptographic algorithm, and the matrix is utilized to perform column obfuscation operation. The diffusion layer formed by the MDS matrix can optimally resist differential attacks and linear attacks, and the security of the algorithm in the technical scheme can be further improved when the diffusion layer is applied to the technical scheme of the invention.

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31 Jul 2020

TL;DR: In this paper, a block cipher MEG implementation method and device and a storage medium are described, and a novel secret key expansion mode is provided, i.e., matrix multiplication on a finite field is carried out by using a generation matrix of a maximum distance separable code which can be used for constructing an optimal diffusion layer and an original secret key, so that the operation of expanding the original key is completed.

Abstract: The invention discloses a block cipher MEG implementation method and device and a storage medium. According to the technical scheme of the invention, a novel secret key expansion mode is provided, i.e., matrix multiplication on a finite field is carried out by using a generation matrix of a maximum distance separable code which can be used for constructing an optimal diffusion layer and an original secret key, so that the operation of expanding the original secret key is completed. An extended generalized Feistel structure is adopted, and an optimal diffusion layer is generated after four times of iteration and used for column obfuscation operation. The optimal diffusion layer not only has ideal confusion characteristics, but also has the best effect of resisting differential attacks and linear attacks, so that the security of the algorithm can be further improved. According to the technical scheme provided by the invention, when hardware is realized, the matrix used for key expansionis a cyclic matrix, and the original key can be expanded only by storing 16-bit elements, so that the storage space is saved and the resource occupation area of the algorithm is reduced while the security of the cryptographic algorithm is improved.

##### Cited by

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16 Feb 2018

TL;DR: In this article, an SP network structure lightweight LBT block cipher realizing method with consistent encryption and decryption is presented. But the cipher structure is same with a Feistel network cipher structure.

Abstract: The invention discloses an SP network structure lightweight LBT block cipher realizing method with consistent encryption and decryption. The invention provides an SP network cipher structure with consistent encryption and decryption. The cipher structure is same with a Feistel network cipher structure. One algorithm is utilized in encryption and decryption, and designing of a special decryption algorithm is not required. According to the cipher structure, a plaintext data input direction for encryption is same with a cipher text data input direction for decryption. The designed cipher structure is realized as a lightweight LBT block cipher algorithm. A user selects different secret key length cipher algorithms according to an application occasion requirement. The SP network structure lightweight LBT block cipher realizing method has advantages of settling a bottleneck of high difficulty of realizing consistent encryption and decryption based on the SP network structure password, realizing high encryption speed and high decryption speed of the LBT cipher, facilitating software and hardware realization, reducing software resource and hardware resource, and realizing high suitabilityfor use as the lightweight block cipher.

7 citations

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18 Dec 2018

TL;DR: In this article, a recoverable lightweight desensitization method of reserved digital type was proposed, which uses 10 integers from 0 to 9, encrypts by lightweight block cipher algorithm to obtain ciphertext size distribution sequence, and takes the distribution sequence as digital type forward permutation table.

Abstract: The invention discloses a recoverable lightweight desensitization method of reserved digital type. The method uses 10 integers from 0 to 9, encrypts by lightweight block cipher algorithm to obtain ciphertext size distribution sequence, and takes the distribution sequence as digital type forward permutation table. The real digital data to be desensitized is added one by one with the encryption key,the 10 modulo operation is operated, and then the digital forward replacement table is replaced to desensitize, and the digital false data is obtained after desensitization, and the desensitizationof the data is completed. On the basis of the digital forward permutation table, a digital inverse permutation table is constructed. The desensitized pseudo-digital data is permuted and recovered, andthen subtracted one by one with the encryption key, and the 10 modulo operation is operated, so that the desensitized pseudo-data is recovered to obtain the real digital data. The method can keep the data format before desensitization and the data format after desensitization unchanged, realize data concealment, and carry out efficient and safe desensitization treatment and desensitization recovery for digital data of any length, thus saving the overhead of software realization and the cost of hardware realization.

1 citations

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05 Jun 2018

TL;DR: In this article, a lightweight block cipher SCS is proposed, where a turn key and a control key are divided in keys, the round key participates in a round key adding operation, the control key controls the generation of each turn of S box to obtain a random S box, the update of the control and the turn key is related to the operation result of the last turn, the Sbox used in each turn is random, the operation results of each round is also random, so that the degree of confusion can be increased, and after the end of the round function iteration

Abstract: The invention discloses a method and apparatus for implementing a lightweight block cipher SCS. A turn key and a control key are divided in keys, the round key participates in a round key adding operation, the control key controls the generation of each turn of S box to obtain a random S box, the update of the control key and the turn key is related to the operation result of the last turn, the Sbox used in each turn is random, the operation result of each turn is also random, so that the degree of confusion can be increased; in a round function, a high pseudo-random P permutation is generated by the Mason rotation algorithm in each round to achieve the diffusion, and after the end of the round function iteration, row shift and the column confusion transform are executed, so that the diffusion effect is enhanced by using the dual diffusion mode, and the security is improved. Compared with the situation that the difference between the resource consumption of fixed cipher structures isnot large, the internal structure of the device has the advantages of greatly improving the security of the scheme, and increasing the defense coefficients of linear attack, differential attack and the like to a certain extent.

1 citations

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09 Jan 2020

TL;DR: In this paper, a method for the conversion of plain text into cipher text is described, where the plain text is split into first and second half, and the first half is EX-OR with corresponding round keys.

Abstract: Disclosed is a system and method for the conversion of plain text into cipher text. The system comprises a processor (201) and memory (203). The processor receives a block of plain text. The steps for said conversion comprises applying an initial permutation function to the plain text. The text is split into first and second half. The first half is EX-OR (205) with a round function (305). A plurality of S-boxes are mapped with processed first half. An inverter function (306) is applied to mapped bits. A processed second half is generated by EX-ORing bits from the inverter with second half and corresponding round key. The processed first and second half are swapped. Further, first and second half are EX-OR with corresponding round keys. An inverse initial permutation function (309) is applied after combined first and second half, thereby generating cipher text (310) of equal bits of plain text (301).

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09 Jun 2020

TL;DR: In this paper, a method and a device for realizing a Shield block cipher generated by a novel secret key, and a readable storage medium was presented, where the Shield grouping length is designed to be 128 bits, a secret key is any length, an encryption round function is based on an SPN structure, and the encryption sequence is round secret key addition, S box replacement, row shifting and column hybrid transformation in sequence.

Abstract: The invention discloses a method and a device for realizing a Shield block cipher generated by a novel secret key, and a readable storage medium. According to the method, the Shield grouping length isdesigned to be 128 bits, a secret key is any length, an encryption round function is based on an SPN structure, and the encryption sequence is round secret key addition, S box replacement, row shifting and column hybrid transformation in sequence. The secret key expansion function divides an original secret key into three parts, generates three round secret keys by using a hash function MD5, anduses the round secret keys in different rounds of addition operation. According to the S box replacement transformation, 128-bit data replacement transformation is carried out by adopting two 4 * 4 Sboxes; the data are divided into 32 4-bit units; and along with the change of encryption/decryption rounds, the data units respectively carry out corresponding S box increasing/decreasing replacementoperation. According to the invention, the occupied area resource of the Shield cipher is small; the storage space for storing the original secret key is reduced; and the known attack can be well resisted by increasing the length of the secret key and expanding the secret key space.