Abstract: Aimed at the problems of low attribute revocation efficiency and difficult coordination of user keys in existing attribute-based encryption, a multi authority-attribute encryption scheme based on blockchain is constructed by combining blockchain and attribute based encryption. This scheme used multiple attribute authorities to generate attribute private keys for users in parallel, and used smart contracts and distributed ledgers to record the mapping relationship between users and their attributes to achieve distributed distribution and revocation of attribute private keys, so that attribute revocation did not require attribute private key update, and reduced user computing overhead. The security proof and efficiency analysis show that this scheme not only improves the efficiency of attribute private key revocation, but also guarantees the forward and backward security of data.