Anonymous signature scheme
In order to hide the identity of a signer, an anonymous signaure scheme is presented in this paper. In this scheme, a signer located in a specified group produces a signautre on behalf of the group. The recipient can verify whether the signature is valid and comes from the specified group, while tracing the signature to its source is impossible. The proposed anonymous signature is similarly to ring signature in some respects, for example, there is no manager, and no revocation mechanism against signer's anonymity. The most different between these two kinds of signatures is that the group in ring signature is adaptively constructed by the signer, while the group in our scheme is fixed.
Proxy Key Re-encapsulation Mechanism for Group Communications
Many practical applications use hybrid encryption mechanism to deal with large plaintext messages or real-time communication since the performance of the public key encryption scheme is poor. The key encapsulation is a crucial part in hybrid encryption mechanism, which allows a sender to generate a random session key and distribute it to recipient. In this paper we present a proxy key re-encapsulation scheme for group communication. The proxy in our scheme is allowed to transform the encapsulated message corresponding to group A's public key into one that can be decapsulated by the member in group B. It can be used in cases when a group users need to perform sensitive operation without holding the necessary secret key.
Revisit of Group-based Unidirectional Proxy Re-encryption Scheme
Currently, researchers have focused their attention on proxy re-encryption scheme deployed between two entities. Lots of bidirectional schemes have been proposed and this kind of scheme is suitable for the scenario in which the two entities have already established a relationship of trust. How to construct a unidirectional scheme is an open problem and receiving increasing attention. In this paper, we present a unidirectional proxy re-encryption scheme for group communication. In this scheme, a proxy is only allowed to convert ciphertext for Alice into ciphertext for Bob without revealing any information on plaintext or private key. It is suitable for the environment in which no mutual relationship exists and transitivity is not permitted. We prove the scheme secure against chosen ciphertext attack in standard model.
Provable password-based tripartite key agreement protocol
A password-based tripartite key agreement protocol is presented in this paper. The three entities involved in this protocol can negotiate a common session key via a shared password over insecure networks. Proofs are given to show that the proposed protocol is secure against forging and chosen message attacks in the case of without actually running a dictionary attack.
Scalable Storage Scheme from Forward Key Rotation
Kallahalla et al. presented a RSA-based Forward Key Rotation mechanism in secure storage scheme PLUTUS to ensure that the key used for encrypting updated files is related to the keys for all files in the file group. The encryption scheme based on Forward Key Rotation is such a scheme that only the authorized person is allowed access to the designated files and the previous versions. In this paper, we present a Forward Key Rotation storage scheme based on discrete logarithm and prove its security under random oracle model. Moreover, we propose another improved Forward Key storage scheme from pairing on elliptic curves. Compared to the scheme presented by Kallahalla et al., our scheme uses relatively short keys to provide equivalent security. In addition, the re-generated keys can be verified to ensure that the keys are valid in the improved scheme.
Group-based Proxy Re-encryption scheme
Recently, proxy re-encryption scheme received much attention. In this paper, we propose a proxy re-encryption used for divert ciphertext from one group to another. The scheme is bidirectional and any member can independently decrypt the ciphertexts encrypted to its group. We discuss the security of the proposed scheme and show that our scheme withstands chosen ciphertext attack in standard model.
Group-oriented encryption secure against collude attack
A group oriented encryption scheme is presented in this paper. In this scheme, a sender is allowed to encrypt a message using the group public key and send the ciphertext to the group. Any user in the group can independently decrypt the ciphertext via his private key. The scheme is secure against adaptively chosen ciphertext attack and collude attack.
Chameleon-Based Deniable Authenticated Key Agreement Protocol
As a useful means of safeguarding privacy of communications, deniable authentication has received much attention. A Chameleon-based deniable authenticated key agreement protocol is presented in this paper. The protocol has following properties. Any one of the two participants canât present a digital proof to convince a third party that a claimed agreement has really taken place. Once a forgery occurs, the original entity can present a digital proof to disclose the forgery.
Adaptable Group-Oriented Signature
A new type of signature is presented in this paper, named adaptable group-oriented signature. In contrast with traditional group-oriented signature, the new one laid a strong emphasis on how to improve the signer??s efficiency. In fact, this new type of group-oriented signature can be seen as a type of designated verifier signature. In contrast with the ordinary designated verifier signature, it does not designate one member but several members to independently verify the signature. The designated members, who can independently verify the signature, come into a group. This scheme can ensure the anonymity of the verifiers. This type of signature can be used in such system that the compute resource is limited, such as the broadcast protocols of the mobile telephone in the mobile networks.