A New Signcryption Scheme Based on Elliptic Curves

Abstract

Based on the intractable problem of discrete logarithm in ECC and the intractability of reversing a one-way hash function, this paper presents a signcryption scheme with public verifiability and forward security. In the process of security proof, the unforgeability ensures that the attacker can’t create a valid ciphertext. We verify the cipher text $c$ instead of the plain text $m$ in verification phase. We protect the plain text $m$, which makes the proposed scheme confidential. Thus, the proposed scheme has the property of public verification. And the scheme ensures that if the sender’s private key is compromised, but the attacker can’t recover original message $m$ from cipher text $(c,R,s)$. By the performance analysis, our proposed scheme mainly uses the model multiplication. Compared with Zhou scheme, the number of model multiplication has lost one time in signcryption phase, which leads to the significant increase in calculation rate. Moreover, the signature length has lost $2|n|$ compared with Zhou scheme. In other words, the minimum value of complexity is reached in theory. This makes the scheme have higher security and wider applications.