Methods, systems, and apparatus, including computer programs encoded on computer storage media, for blockchain-based decentralized-identifier authentication, are provided. One of the methods includes: obtaining a request for authenticating a decentralized identifier (DID), wherein the request comprises the DID, a plaintext associated with a challenge for authenticating the DID, and a digital signature on the plaintext; obtaining a public key associated with the DID; determining, based on the obtained public key and the plaintext, that the digital signature on the plaintext is created based on a private key corresponding to the DID; and generating, based on the determination, a message confirming authentication of the DID.