A new forward secure content extraction signature scheme

We design a content extraction signature with a forward secure based on short signature. The scheme can cut the risk of the key leakage to the lowest degree, and get verifiable content extraction with minimal multi-party interaction. The secret key in this new scheme is updated automatically with different period time while the public key is fixed in the all lifetime, even if the secret key of current time period is compromised, the attacker cannot forge the secret key and the signature of the past period time. We also prove that our scheme is existential forgery on adaptively chosen message attack in the random oracle model.