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, from a computing device, a request for creating an authentication challenge for a decentralized identifier (DID); obtaining, from a blockchain network, a DID document corresponding to the DID; retrieving a public key associated with the DID from the received DID document; creating the authentication challenge by encrypting a piece of original text using the public key to create a piece of ciphertext; obtaining information associated with an authentication service endpoint for the DID from the received DID document; sending, to the authentication service endpoint according to the obtained information, the created authentication challenge.