Data modification method based on alliance chain

The invention provides a data modification method based on an alliance chain. The method comprises the following steps: randomly generating a chameleon hash public and private key pair and a variable parameter for each transaction, and generating a hash value of the transaction by using a chameleon hash algorithm; for each transaction, encrypting the chameleon hash private key corresponding to the transaction according to the user public key of each transaction user by using a multi-party key negotiation algorithm to generate a chameleon hash private key ciphertext; performing uplink storage on each transaction and the corresponding chameleon hash private key ciphertext at the same time; when the historical transaction stored on the chain needs to be modified, all transaction users participating in the historical transaction restore the chameleon Hash private key ciphertext stored on the chain by using a multi-party key negotiation algorithm to obtain a chameleon Hash private key, and complete Hash collision