Tuan Nguyen Kim^1,*, Duy Ho Ngoc², Nikolay A. Moldovyan³

CMC-Computers, Materials & Continua, Vol.74, No.1, pp. 1475-1491, 2023, DOI:10.32604/cmc.2023.029253

Abstract The representative collective digital signature, which was suggested by us, is built based on combining the advantages of group digital signature and collective digital signature. This collective digital signature schema helps to create a unique digital signature that deputizes a collective of people representing different groups of signers and may also include personal signers. The advantage of the proposed collective signature is that it can be built based on most of the well-known difficult problems such as the factor analysis, the discrete logarithm and finding modulo roots of large prime numbers and the current digital signature standards of the United… More >

Tuan Nguyen Kim^1,*, Duy Ho Ngoc², Nikolay A. Moldovyan³

CMC-Computers, Materials & Continua, Vol.73, No.1, pp. 783-799, 2022, DOI:10.32604/cmc.2022.024677

Abstract The representative collective digital signature scheme allows the creation of a unique collective signature on document M that represents an entire signing community consisting of many individual signers and many different signing groups, each signing group is represented by a group leader. On document M, a collective signature can be created using the representative digital signature scheme that represents an entire community consisting of individual signers and signing groups, each of which is represented by a group leader. The characteristic of this type of letter is that it consists of three elements (U, E, S), one of which (U) is… More >

Tuan Nguyen Kim^1,*, Duy Ho Ngoc², Nikolay A. Moldovyan³

CMC-Computers, Materials & Continua, Vol.73, No.1, pp. 595-610, 2022, DOI:10.32604/cmc.2022.023168

Abstract There have been many digital signature schemes were developed based on the discrete logarithm problem on a finite field. In this study, we use the elliptic curve discrete logarithm problem to build new collective signature schemes. The cryptosystem on elliptic curve allows to generate digital signatures with the same level of security as other cryptosystems but with smaller keys. To extend practical applicability and enhance the security level of the group signature protocols, we propose two new types of collective digital signature schemes based on the discrete logarithm problem on the elliptic curve: i) the collective digital signature scheme shared… More >

Tuan Nguyen Kim^1,*, Duy Ho Ngoc², Nikolay A. Moldovyan³

CMC-Computers, Materials & Continua, Vol.72, No.1, pp. 1105-1122, 2022, DOI:10.32604/cmc.2022.025653

Abstract Digital signature schemes are often built based on the difficulty of the discrete logarithm problems, of the problem of factor analysis, of the problem of finding the roots modulo of large primes or a combination of the difficult problems mentioned above. In this paper, we use the new difficult problem, which is to find the root in the finite ground field to build representative collective signature schemes, but the chosen modulo p has a special structure distinct , where is an even number and are prime numbers of equal magnitude, about . The characteristics of the proposed scheme are: i)… More >