PS基于身份数字签名算法的改进

Improvement on PS Identity Based Signature Scheme

PS(Paterson and Schuldt)算法直接利用两组独立的Waters身份处理函数分别处理用户身份和签名消息,该算法的安全归约效率很低。为此,改进了Waters身份处理函数的参数选择方法,并将其应用于PS签名算法安全证明的改进,使新的基于身份数字签名算法安全归约效率大大提高,从PS方案的O((qkn)-2)提高到O((qkn(n^1/2))-1),从而使新算法更加安全、可信。

In the standard model an unforgeable chosen message attacks security IBS（Identity-Based Signature） scheme was proposed by PS（Paterson and Schuldt）,which was based on computational Diffie-Hellman problem in bilinear pairing group.Two independent Waters identity hash functions were directly employed to treat the users identity and the signature message respectively,so PSs IBS scheme had poor security reduction efficiency.An improved Waters identity hash function parameters selecting method was proposed.The new method was employed to improve PSs IBS signature scheme,which made the security reduction efficiency of the new IBS scheme having greatly improvementfrom O（（qkn）^-2） to O（（qkn（√n）^-1）,so the improved scheme was more security and trustable.