Secure and Anonymous Communication Technique: Formal Model and Its Prototype Implementation

Abstract

Both anonymity and end-to-end encryption are recognized as important properties in privacy-preserving communication. However, secure and anonymous communication protocol that requires both anonymity and end-to-end encryption cannot be realized through a simple combination of current anonymous communication protocols and public key infrastructure (PKI). Indeed, the current PKI contradicts anonymity because the certificate for a user's public key identifies the user. Moreover, we believe that anonymous communication channels should have certain authentication mechanisms because such a channel could incubate criminal communication. To cope with this issue, we propose a secure and anonymous communication protocol by employing identity-based encryption for encrypting packets without sacrificing anonymity, and group signature for anonymous user authentication. Communication occurs in the protocol through proxy entities that conceal user IP addresses from service providers (SPs). We also introduce a proof-ofconcept implementation to demonstrate the protocol's feasibility and analyze its performance. Finally, we conclude that the protocol realizes secure and anonymous communications between users and SPs with practical performance.

Ensuring Secure and Anonymous Data Transmission using Proxy Server

“…A formal method for secure and anonymous communication and its prototype implementation is introduced by Keita et al [1]. In this some proxy entities are used which can mask the IP address from the service providers.…”

A KEM/DEM-Based Construction for Secure and Anonymous Communication

“…In this paper, we point out that no IBE is required for constructing a secure and anonymous communication protocol, and we construct a more efficient protocol that archives the same security level as the IBE-based protocol [1], [2] does. By modifying the protocol syntax properly, we can apply the KEM/DEM framework [5] 1 for establishing a secure channel instead of IBE; a session key is encapsulated by the KEM part, and the actual data is encrypted by the DEM part.…”

“…That is, although the user additionally needs to compute a ciphertext by using the SP public key (which can be certified by PKI) for establishing a secure channel, no pairing computation is required for decryption or encryption by the user or the SP, respectively. As a remark, we can interpret that the IBE-based construction [1], [2] delegates such an encryption cost from the user to the SP.…”

“…Figure 1 depicts the overview of the proposed protocol. There are four roles: User, Proxy, Service Provider (SP), and GM, as in [1], [2]. One difference is that we do not assume any trusted KGC, whereas we assume a PKI system.…”

“…To cope with these problems, a secure and anonymous communication protocol was proposed in [1], [2], where a service provider (SP) can send encrypted content to a user while simultaneously and anonymously authenticating the user. The protocol employs identity-based encryption (IBE) [3] to encrypt contents without identifying key holders and employs a group signature [4] for anonymous user authentication.…”