certificateless public key cryptography (cl-pkc) is a useful method in order to solve the problems of traditional public key infrastructure (i. e. large amount of computation, storage and communication cost for managing certificates) and id-based public key cryptography (i. e. key escrow problem), simultaneously. a signcryption scheme is an important primitive in cryptographic protocols which p...

In this letter, we will show that the certificateless signature scheme recently proposed by Yap, Heng and Goi at EUC Workshops 2006 is insecure against a key replacement attack. Our attack shows that anyone who replaces a signer’s public key can forge valid signatures for that signer without knowledge of the signer’s private key.

“Certificateless Public Key Cryptography” has very appealing features, namely it does not require any public key certification (cf. traditional Public Key Cryptography) nor having key escrow problem (cf. Identity-Based Cryptography). Unfortunately, construction of Certificateless Public Key Encryption (CLPKE) schemes has so far depended on the use of Identity-Based Encryption, which results in ...

Certificateless public key cryptography is a new paradigm with two interesting features. On one hand, it keeps the certificate free property of identity-based public key cryptography (ID-PKC), while on the other hand, it gets rid of the inherent key escrow problem of ID-PKC. These two distinctive features make certificateless threshold signature schemes more applicable in practice as it removes...

Certificateless public key cryptography (CL-PKC) is a useful method in order to solve the problems of traditional public key infrastructure (i.e., large amount of computation, storage and communication costs for managing certificates) and ID-based public key cryptography (i.e., key escrow problem), simultaneously. A signcryption scheme is an important primitive in cryptographic protocols which ...

A well-known attack on RSA with low secret-exponent d was given by Wiener in 1990. Wiener showed that using the equation ed − (p − 1)(q − 1)k = 1 and continued fractions, one can efficiently recover the secret-exponent d and factor N = pq from the public key (N, e) as long as d < 1 3 N 1 4 . In this paper, we present a generalization of Wiener’s attack. We show that every public exponent e that...

Certificateless cryptography involves a Key Generation Center (KGC) which issues a partial key to a user and the user also independently generates an additional public/secret key pair in such a way that the KGC who knows only the partial key but not the additional secret key is not able to do any cryptographic operation on behalf of the user; and a third party who replaces the public/secret key...

In this paper, we show that Chikazawa-Inoue ID-based key system is insecure by collusion, where Chikazawa-Inoue ID-based key system means the key parameters established during the initiation phase. We describe an algorithm factorizing a public key of Trust Center. Since our attack is based on only the key system and has no relation with specific key sharing protocols, it can be applied to all v...

P2P network is open, anonymous and dynamical in contrast with conventional network. It’s full of dishonesty, deceit, selfishness. It’s necessary to build a robust security infrastructure system. The one important module of security infrastructure is to identify the users in transactions. This paper will propose an identification solution based on PKI. In our algorithm, the peer generates their ...

—In this paper, we propose two certificate mechanisms for preventing the Sybil attack in a vehicular ad hoc network (VANET): the timestamp series approach and the temporary certificate approach. We focus on an early-stage VANET when the number of smart vehicles is only a small fraction of the vehicles on the road and the only infrastructure components available are the roadside units (RSUs). Un...