This paper investigates a novel computational problem, namely the Composite Residuosity Class Problem, and its applications to public-key cryptography. We propose a new trapdoor mechanism and derive from this technique three encryption schemes: a trapdoor permutation and two homomorphic probabilistic encryption schemes computationally comparable to RSA. Our cryptosystems, based on usual modular...

In this work, we aim to reduce the computational costs of using public-key digital signatures in securing routing protocols. Two protocols (COSP and IOSP) using one-time digital signatures are introduced to provide the functionality of public-key digital signatures. Our protocols are intended to be used in place of public-key digital signatures for signing all kinds of message exchanges among r...

Certificateless cryptosystems were proposed by Al-Riyami and Paterson in 2003 [1] to solve problems of public key cryptosystems based on PKI and based on identity. Up to now, various types of certificateless cryptographic primitives as encryption functions, signature schemes, key agreement protocols and etc, have been designed. But to the best of our knowledge, multiple-key agreement protocols ...

This paper proposes two new public-key cryptosystems semantically secure against adaptive chosen-ciphertext attacks. Inspired from a recently discovered trap-door technique based on composite-degree residues, our converted encryption schemes are proven, in the random oracle model, secure against active adversaries (NM-CCA2) under the assumptions that the Decision Composite Residuosity and Decis...

In this paper, we consider what condition is sufficient for random inputs to secure probabilistic public-key encryption schemes. Although a framework given in [16] enables us to discuss uniformly and comprehensively security notions of public-key encryption schemes even for the case where cryptographically weak pseudorandom generator is used as random nonce generator to encrypt single plaintext...

Algorithms best suired forflexible smart card applications are based on public key cryptosystems RSA, zero-knowiedge protocols . . . Their practical implementation (execution in =:I second) entails a computing power beyond the reach of classical smart cards, since large integers (512 bits) have to be manipulated in complex ways (exponentiation). CORSAIR achieves up to 40 (8 bit) MIPS with a clo...

This paper proposes two new public-key cryptosystems semantically secure against adaptive chosen-ciphertext attacks. Inspired from a recently discovered trapdoor technique based on composite-degree residues, our converted encryption schemes are proven, in the random oracle model, secure against active adversaries (IND-CCA2) under the assumptions that the Decision Composite Residuosity and Decis...

Since the Diffie-Hellman paper, asymmetric encryption has been a very important topic, and furthermore ever well studied. However, between the efficiency of RSA and the security of some less efficient schemes, no trade-off has ever been provided. In this paper, we propose better than a trade-off: indeed, we first present a new problem, derived from the RSA assumption, the “Dependent–RSA Problem...

For public key cryptosystems multiplication on elliptic curves can be used instead of exponentiation in finite fields. One attack to such a system is: embedding the elliptic curve group into the multiplicative group of a finite field via weilpairing; calculating the discrete logarithm on the curve by solving the discrete logarithm in the finite field. This attack can be avoided by constructing ...