scholarly journals Alternative Certificate Formats for the Public-Key Infrastructure Using X.509 (PKIX) Certificate Management Protocols

2005 ◽  
Author(s):  
M. Blinov ◽  
C. Adams
Keyword(s):  
Public Key Infrastructure ◽  
Public Key ◽  
The Public ◽  
Certificate Management

scholarly journals A Collusion-Resistant Identity-Based Proxy Reencryption Scheme with Ciphertext Evolution for Secure Cloud Sharing

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Shimao Yao ◽  
Ravi Sankar ◽  
In-Ho Ra
Keyword(s):  
Data Security ◽  
Computing Time ◽  
Public Key Infrastructure ◽  
Public Key ◽  
The Public ◽  
User Data ◽  
Identity Based ◽  
Certificate Management ◽  
Simulation Results ◽  
Authorization Delegation

In order to solve the challenges of user data security in the cloud computing (storage) environment, many encryption solutions with different features have been presented. Among them, proxy reencryption (PRE) based on public-key infrastructure (PKI) is a promising technology for secure cloud sharing. And identity-based proxy reencryption (IBPRE), which uses identity as the public key, eliminates burdensome certificate management and is, therefore, more preferable. However, most of the current IBPRE schemes only focus on the processing of data sharing while overlooking the functions of authorization revocation and ciphertext update, which are more closely related to the security of data itself. Moreover, the few existing schemes that involve ciphertext update turn out to be impractical because the length of ciphertext increases with the reencryption of ciphertext. In this paper, an improved IBPRE scheme, which provides improvements on the inadequacies of the scheme proposed by Ateniese et al. especially in terms of collusion safety and ciphertext evolution, is proposed. To the best of our knowledge, this is a practical IBPRE scheme integrating the functions of access authorization, delegation revocation, ciphertext update, reauthorization, and conditional reservation delegation. The proposed technique has high practicability in the scenario where a large number of ciphertexts need to be updated synchronously. Lastly, the comparative analysis and simulation results show that the two reencryption algorithms in the proposed scheme have the shortest computing time than other schemes.

scholarly journals Dynamic Public Key Certificates with Forward Secrecy

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 2009
Author(s):  
Hung-Yu Chien
Keyword(s):  
Public Key Infrastructure ◽  
Public Key ◽  
Practical Reasons ◽  
Forward Secrecy ◽  
The Public ◽  
Private Key ◽  
Security Properties ◽  
The Subject ◽  
Key Exposure ◽  
Chameleon Hash

Conventionally, public key certificates bind one subject with one static public key so that the subject can facilitate the services of the public key infrastructure (PKI). In PKI, certificates need to be renewed (or revoked) for several practical reasons, including certificate expiration, private key breaches, condition changes, and possible risk reduction. The certificate renewal process is very costly, especially for those environments where online authorities are not available or the connection is not reliable. A dynamic public key certificate (DPKC) facilitates the dynamic changeover of the current public–private key pairs without renewing the certificate authority (CA). This paper extends the previous study in several aspects: (1) we formally define the DPKC; (2) we formally define the security properties; (3) we propose another implementation of the Krawczyk–Rabin chameleon-hash-based DPKC; (4) we propose two variants of DPKC, using the Ateniese–Medeiros key-exposure-free chameleon hash; (5) we detail two application scenarios.

scholarly journals LogPicker: Strengthening Certificate Transparency Against Covert Adversaries

2021 ◽  
Vol 2021 (4) ◽  
pp. 184-202
Author(s):  
Alexandra Dirksen ◽  
David Klein ◽  
Robert Michael ◽  
Tilman Stehr ◽  
Konrad Rieck ◽  
...  
Keyword(s):  
Distributed System ◽  
Large Scale ◽  
Public Key Infrastructure ◽  
Third Party ◽  
Public Key ◽  
Smooth Transition ◽  
Certificate Authority ◽  
Trusted Third Party ◽  
The Public

Abstract HTTPS is a cornerstone of privacy in the modern Web. The public key infrastructure underlying HTTPS, however, is a frequent target of attacks. In several cases, forged certificates have been issued by compromised Certificate Authorities (CA) and used to spy on users at large scale. While the concept of Certificate Transparency (CT) provides a means for detecting such forgeries, it builds on a distributed system of CT logs whose correctness is still insufficiently protected. By compromising a certificate authority and the corresponding log, a covert adversary can still issue rogue certificates unnoticed. We introduce LogPicker, a novel protocol for strengthening the public key infrastructure of HTTPS. LogPicker enables a pool of CT logs to collaborate, where a randomly selected log includes the certificate while the rest witness and testify the certificate issuance process. As a result, CT logs become capable of auditing the log in charge independently without the need for a trusted third party. This auditing forces an attacker to control each participating witness, which significantly raises the bar for issuing rogue certificates. LogPicker is efficient and designed to be deployed incrementally, allowing a smooth transition towards a more secure Web.

Certificates and Public Key Infrastructure

2008 ◽  
pp. 217-245
Author(s):  
Manuel Mogollon
Keyword(s):  
Access Control ◽  
Digital Signature ◽  
Public Key Infrastructure ◽  
Public Key ◽  
Comprehensive System ◽  
Public Key Encryption ◽  
Control Data ◽  
The Public ◽  
Digital Certificates ◽  
Public Keys

In public-key encryption, the secrecy of the public key is not required, but the authenticity of the public key is necessary to guarantee its integrity and to avoid spoofing and playback attacks. A user’s public key can be authenticated (signed) by a certificate authority that verifies that a public key belongs to a specific user. In this chapter, digital certificates, which are used to validate public keys, and certificate authorities are discussed. When public-key is used, it is necessary to have a comprehensive system that provides public key encryption and digital signature services to ensure confidentiality, access control, data integrity, authentication, and non-repudiation. That system, public-key infrastructure or PKI, is also discussed in this chapter.

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