Provided are a blockchain-based data processing method and apparatus, a device, and a storage medium, which relate to the field of blockchain technology and can be used for cloud computing and cloud services. The specific implementation is: in response to a data usage request initiated by a data user, acquiring a signature result from an entrusted signer associated with to-be-used data after the entrusted signer audits the data user; calling a lease smart contract according to the data usage request to determine a signature verification key of the entrusted signer associated with the to-be-used data; performing verification on the signature result according to the signature verification key; and in a case where the verification passes, feeding back the to-be-used data to the data user. Therefore, the usage security of data can be improved.