Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement (CB-AK) protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart’s protocol.
Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement (CB-AK) protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart’s protocol.
Key escrow is a default property that is inherent in identity-based cryptography, where a curious private key generator (PKG) can derive a secret value shared by communicating entities in its domain. Therefore, a dishonest PKG can encrypt and decrypt ciphers or can carry out any attack on the communicating parties. Of course, the escrow property is not completely unwanted but is acceptable in other particular applications. On the other hand, in more civil applications, this key escrow property is undesirable and needs to be removed to provide maximum communication privacy. Therefore, this paper presents an escrow-free identity-based key agreement protocol that is also applicable even in a distinct PKG condition that does not use pairings. The proposed protocol has comparable computational and communicational performance to many other protocols with similar security attributes, of which their security is based on costly bilinear pairings. The protocol’s notion was inspired by McCullagh et al. and Chen-Kudla, in regard to escrow-free and multi-PKG key agreement ideas. In particular, the scheme captures perfect forward secrecy and key compromise impersonation resilience, which were lacking in McCullagh et al.’s study, as well as all other desirable security attributes, such as known key secrecy, unknown key-share resilience and no-key control. The merit in the proposed protocol is the achievement of all required security requirements with a relatively lower computational overhead than many other protocols because it precludes pairings.
Abstract. There are several essential features in key agreement protocols such as key escrow (essential when confidentiality, audit trail and legal interception are required) and perfect forward secrecy (i.e., the security of a session key established between two or more entities is guaranteed even when the private keys of the entities are compromised). Majority of the existing escrowable identity-based key agreement protocols, however, only provide partial forward secrecy. Therefore, such protocols are unsuitable for real-word applications that require a stronger sense of forward secrecy — perfect forward secrecy. In this paper, we propose an efficient perfect forward secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Bilinear Diffie-Hellman (GBDH) problem. Security proofs are invaluable tools in assuring protocol implementers about the security properties of protocols. We note, however, that many existing security proofs of previously published identity-based protocols entail lengthy and complicated mathematical proofs. In this paper, our proof adopts a modular approach and, hence, simpler to follow.
To provide secure communications in open and distributed environments, authenticated key agreement protocol is an important primitive for establishing session key. So far, great deals of identity-based protocols have been proposed to provide robust mutual authentication and key establishment in two-party setting. Majority of the existing escrowable identitybased key agreement protocols, however, only provide partial forward secrecy. Therefore, such protocols are unsuitable for real-world applications that require a stronger sense of forward secrecy -- perfect forward secrecy. In this paper, we present a secure two-party identity-based authenticated key agreement protocol, which was inspired on an identity-based encryption scheme first proposed by Gentry (Eurocrypt'06). The proposed protocol achieves most of the required security attributes and can be used properly in the escrow mode. We show that the scheme achieves the attributes of known-key secrecy, key-compromise impersonation resilience, unknown key-share resilience and no key control. In addition, it captures the perfect forward secrecy attribute.
Authenticated key agreement protocol is an important primitive for establishing session key to provide secure communications in open and distributed environment. Key escrow is essential in situations where confidentiality and audit trail are legal requirements, whilst perfect forward secrecy is desirable to provide stronger security. i.e. the adversary couldn't acquire the past session keys even the long term key of user was compromised. In this paper, we present a secure two-party identity-based authenticated key agreement protocol, which was inspired on a new identity-based encryption scheme first proposed by Gentry (Eurocrypt'06). The new protocol achieves most of the required security attributes and can be used properly in the escrow mode. We show that the scheme achieves the attributes of known-key secrecy, key-compromise impersonation resilience, unknown key-share resilience and no key control. In addition, it captures the perfect forward secrecy attribute.
Authenticated key agreement (AK) protocol is crucial in providing data confidentiality and integrity for subsequent communications among two or more parties over a public network. Certificateless public key cryptography (CL-PKC) combines the advantage of the identity-based public key cryptography (ID-PKC) and the traditional public key cryptography (PKC). Unfortunately, construction of CL-PKC and AK protocols has so far depended on the use of identity-based encryption, which results in the bilinear pairing-based schemes that need costly operations. We present a secure certificateless authenticated key agreement protocol without paring, based on the certificateless encryption scheme proposed by J. Baek et al. It shows that the newly proposed scheme is of nice efficiency and practical. Moreover, it provides perfect forward secrecy, PKG forward secrecy and almost all the other known security attributes, such as known-key secrecy, key-compromise impersonation resilience, unknown key-share resilience, known session-specific temporary information security, message independence and no key control.
Key agreement protocols are essential for secure communications in open and distributed environments. Identity-based cryptography has become extremely fashionable in the last few years for its special advantages. In this paper, we point out some flaw in the scheme proposed by Wang et al., then we present a two-party identity-based explicit authenticated key agreement protocol with key confirmation, which was inspired on a new identity-based encryption scheme first proposed by Gentry and can be used properly in the escrowless mode. The scheme captures the attributes of known-key secrecy, key-compromise impersonation resilience, unknown key-share resilience, perfect forward secrecy, and no-key control. Especially, the scheme captures the PKG forward secrecy property. The PKG still could not recover all the userspsila past session keys even he knows the long-term private keys of all users.