Proofs of Knowledge on Monotone Predicates and its Application to Attribute-Based Identifications and Signatures

We propose a concrete procedure of the $\Sigma$-protocol introduced by Cramer, Damgård and Schoenmakers at CRYPTO \u2794, which is for proving knowledge that a set of witnesses satisfies a monotone predicate in witness-indistinguishable way; that is, hiding the assignment of truth in the predicate. We provide a detailed procedure by extending the so-called OR-proof

Hybrid Encryption Scheme Using Terminal Fingerprint and Its Application to Attribute-Based Encryption Without Key Misuse

Part 9: CryptographyInternational audienceInternet services make sharing digital contents faster and easier but raise an issue of illegal copying and distribution of those digital contents at the same time. A lot of public key encryption schemes solve this issue. However, the secret key is not completely protected i.e. these kinds of encryption methods do not prevent illegal copying and distribution of secret keys. In this paper, we propose a hybrid encryption scheme that employ terminal fingerprints. This scheme is a template to avoid such misuse of secret keys, and can be applied to, for example, attribute-based encryption schemes. There terminal fingerprint information is used to create a second encryption key and secret key. Since the terminal fingerprint is assumed to be unchangeable and unknowable, we ensure that our secret keys are valid in the terminal where such secret keys were created

Survey and new idea for attribute-based identification scheme secure against reset attacks

Identification schemes are a common one-way authentication technique for a user to prove himself securely to a verifier. However, it is known that identification schemes based on the sigma-protocol are basically insecure against reset attacks. On the other-hand, attribute-based cryptography is a technique which allows for the secure implementation of access policies within a cryptosystem. In this paper, we report on the developments in the area of reset attacks for identification schemes as well as for attribute-based identification schemes. Then we put together a new idea to construct attribute-based identification schemes secure against reset attacks

Cryptanalysis and Improvement of "A Secure Password Authentication Mechanism for Seamless Handover in Proxy Mobile IPv6 Networks".

Proxy Mobile IPv6 is a network-based localized mobility management protocol that supports mobility without mobile nodes' participation in mobility signaling. The details of user authentication procedure are not specified in this standard, hence, many authentication schemes have been proposed for this standard. In 2013, Chuang et al., proposed an authentication method for PMIPv6, called SPAM. However, Chuang et al.'s Scheme protects the network against some security attacks, but it is still vulnerable to impersonation and password guessing attacks. In addition, we discuss other security drawbacks such as lack of revocation procedure in case of loss or stolen device, and anonymity issues of the Chuang et al.'s scheme. We further propose an enhanced authentication method to mitigate the security issues of SPAM method and evaluate our scheme using BAN logic

Comments and improvements of “HOTA: Handover optimized ticket­based authentication in network­based mobility management”

Nowadays, various mobile devices are being an inseparable part of our normal life. Mobile users tend to be connected to the Internet seamlessly, which is provided by mobility management protocols. One of the latest mobility management protocol is Proxy Mobile IPv6 (PMIPv6), which is a networkbased protocol. Authentication mechanism as a critical security procedure is not specified in PMIPv6, hence various authentication methods have been proposed. Lee and Bonin proposed a ticket­based authentication scheme for PMIPv6, which is called HOTA in 2013. Even though, HOTA offers some security protection mechanisms, but is vulnerable to DoS attack. Furthermore, we show other existing drawbacks to the scheme such as vulnerability against de­synchronization attack and Session Hijacking attack. In this paper, we propose an enhancement method to mitigate these security drawbacks. Finally, security and performance of the proposed method are analyzed and compared to HOTA metho

Hybrid Encryption Scheme using Terminal Fingerprint and its Application to Attribute-based Encryption without Key Misuse

AsiaARES 2015 : The 2015 Asian Conference on Availability, Reliability and Security : October 4th-7th, 2015 : Daejeon Convention Center Daejeon, Kore

Identity-Embedding Method for Decentralized Public-Key Infrastructure

The 6th International Conference on Trustworthy Systems (InTrust 2014) : Dec. 16 - Dec. 17 2014, Beijing, ChinaA public key infrastructure (PKI) is for facilitating the authentication and distribution of public keys. Currently, the most com- monly employed approach to PKI is to rely on certificate authorities (CAs), but recently there has been arising more need for decentralized peer-to-peer certification like Webs of Trust. In this paper, we propose an identity-embedding method suitable for decentralized PKI. By embed- ding not only ID of the candidate public-key owner itself but also IDs of his guarantors into PK, we can construct Web of guarantors on public keys. Here guarantors can be chosen arbitrarily by the candidate public- key owner. Our embedding method uses a combination of two public-key cryptosystems; the first cryptosystem is for PKI directly. Here we employ a technique to embed a string into a public key of the first cryptosystem. As such a string, we choose a concatenation of ID of a candidate public-key owner, IDs of his guarantors, and a public key of the second cryptosystem. This embedded public key of the second cryptosystem is used by the candidate public-key owner that he certainly knows the secret key that corresponds to the public key of the first cryptosystem. Then, with an aid of a broadcast mechanism of an updated public-key list on a peer-to-peer network, we can attain the decentralized PKI. Such an embedding method is concretely realized by the RSA encryption with the Lenstra\u27s algorithm, which can be used as the first cryptosystem. As the second cryptosystem, we employ an elliptic curve encryption whose security is equivalent to the security of the RSA encryption, where the former achieves shorter key size than the latter. We write down concrete values of parameters for a realization of the embedding