Enterprise customers use open source SDK to integrate into existing OA or business systems, and personal customers use non-neutral computer and mobile web pages. The offeror and the contractee in the contract chain create accounts in the system, obtain addresses and private keys (private key is the only electronic signature with legal benefits), authenticate their names, and complete the signing of the contract with their private keys. The contract content is distributed stored in all data nodes around the world. Combined with the national secret algorithm series, the data can not be deleted, can not be tampered with, and ensure privacy and security. The same data are recorded and verified by the verification nodes of authoritative judicial bodies such as courts, notaries offices and arbitration commissions. The whole process offeror and the contractee can authorize third party browsing, forensics or revocation based on their digital identity. The whole process is efficient, convenient, legal, effective, safe and reliable.