Abstract:  In order to solve the security problem of forward-secure digital signature scheme based on Elliptic
Curve Cryptography, we analyzed a forward-secure digital signature scheme based on elliptic curve cryptosystem,
and discovered some serious security vulnerability. We proposed a method that can forge signature to attack the
forward-secure digital signature based on elliptic curve cryptosystem, and prove the rationality and correctness.
We improved the scheme, and prove that the scheme of improvement can not forge signature by using the
proposed method.

Key words:  elliptic curve cryptosystem, forward-secure, digital signature