scholarly journals From semigroup action to homomorphic encryption and some related problems in cryptography

2015 ◽  
Vol 18 (3) ◽  
pp. 254-259
Author(s):  
Thuong Tuan Dang ◽  
Tuan Anh Nguyen ◽  
Tran Thi Bao Ngo

In some recent papers, the authors have showed some homomorphic cryptosystems which are particular cases of split exact sequences of groups. By connecting the relation between these ideas to the concept of group action, in this paper, we build a public key exchange protocol based on actions to a group, from its automorphism group and semigroup ℤ under usual multiplication.

Author(s):  
Jorge Chávez-Saab ◽  
Jesús-Javier Chi-Domínguez ◽  
Samuel Jaques ◽  
Francisco Rodríguez-Henríquez

AbstractRecent independent analyses by Bonnetain–Schrottenloher and Peikert in Eurocrypt 2020 significantly reduced the estimated quantum security of the isogeny-based commutative group action key-exchange protocol CSIDH. This paper refines the estimates of a resource-constrained quantum collimation sieve attack to give a precise quantum security to CSIDH. Furthermore, we optimize large CSIDH parameters for performance while still achieving the NIST security levels 1, 2, and 3. Finally, we provide a C-code constant-time implementation of those CSIDH large instantiations using the square-root-complexity Vélu’s formulas recently proposed by Bernstein, De Feo, Leroux and Smith.


Author(s):  
Luis Lizama-Pérez ◽  
J. Mauricio López

Post-quantum public cryptosystems introduced so far do not define an scalable public key infrastructure for the quantum era. We demonstrate here a public certification system based in Lizama’s non-invertible Key Exchange Protocol which can be used to implement a public key infrastructure (PKI), secure, scalable, interoperable and efficient. We show functionality of certificates across different certification domains. Finally, we discuss that non-invertible certificates can exhibit Perfect Forward Secrecy (PFS).


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xuefei Cao ◽  
Lanjun Dang ◽  
Yingzi Luan ◽  
Wei You

In this paper, we propose a certificateless noninteractive key exchange protocol. No message exchange is required in the protocol, and this feature will facilitate the applications where the communication overhead matters, for example, the communications between the satellites and the earth. The public key certificate is removed as well as the key escrow problem using the certificateless public key cryptosystem. The security of the protocol rests on the bilinear Diffie–Hellman problem, and it could be proved in the random oracle model. Compared with previous protocols, the new protocol reduces the running time by at least 33.0%.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tsu-Yang Wu ◽  
Tung-Tso Tsai ◽  
Yuh-Min Tseng

The existence of malicious participants is a major threat for authenticated group key exchange (AGKE) protocols. Typically, there are two detecting ways (passive and active) to resist malicious participants in AGKE protocols. In 2012, the revocable identity- (ID-) based public key system (R-IDPKS) was proposed to solve the revocation problem in the ID-based public key system (IDPKS). Afterwards, based on the R-IDPKS, Wu et al. proposed a revocable ID-based AGKE (RID-AGKE) protocol, which adopted a passive detecting way to resist malicious participants. However, it needs three rounds and cannot identify malicious participants. In this paper, we fuse a noninteractive confirmed computation technique to propose the first two-round RID-AGKE protocol with identifying malicious participants, which is an active detecting way. We demonstrate that our protocol is a provably secure AGKE protocol with forward secrecy and can identify malicious participants. When compared with the recently proposed ID/RID-AGKE protocols, our protocol possesses better performance and more robust security properties.


2011 ◽  
Vol 467-469 ◽  
pp. 640-644
Author(s):  
Yong Ding ◽  
Bin Li ◽  
Zheng Tao Jiang

Affiliation-hiding authenticated key exchange protocol, also called secret handshake, makes two parties from the same organization realize mutual authentication and key agreement via public key certificates without leaking the organization information to any others. Moreover, if the peer involved in the protocol is not from the same group, no any information of the affiliation can be known. In previous secret handshakes protocols, there is a problem which is linkability. That is to say, two activities of the same people can be associated by the attackers. It is not desirable for privacy because the association may deduce it’s affiliation with some other information. In this paper, an unlinkable affiliation-hiding authenticated key exchange protocol is brought out to conquer the linkability. Security analysis is given finally.


Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 226
Author(s):  
Luis Adrián Lizama-Perez ◽  
J. Mauricio López R.

Post-quantum public cryptosystems introduced so far do not define a scalable public key infrastructure for the quantum era. We demonstrate here a public certification system based on Lizama’s non-invertible key exchange protocol which can be used to implement a secure, scalable, interoperable and efficient public key infrastructure (PKI). We show functionality of certificates across different certification domains. Finally, we discuss a method that enables non-invertible certificates to exhibit perfect forward secrecy (PFS).


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