A computer-implemented method for data management, implemented by a first service system (113, 114), comprising: obtaining authentication information of a login user for accessing the first service system; generating a digital abstract of the authentication information of the login user; transmitting the digital abstract of the authentication information of the login user to one or more nodes of a blockchain, wherein the blockchain is accessible to the first service system, a second service system and a storage system independent from the first and the second service systems; obtaining from the one or more nodes of the blockchain a result of a comparison between the digital abstract of the authentication information of the login user and one or more digital abstracts stored on the blockchain, wherein: the comparison is performed by the one or more nodes of the blockchain, the one or more digital abstracts comprise a digital abstract of registered authentication information of the login user for accessing the second service system, said registered authentication information comprising at least one of: i) an account identification associated with the login user; and ii) a password associated with said account identification, the one or more digital abstracts are stored on the blockchain after consensus verification by a plurality of nodes of the blockchain, and the login user is not registered with the first service system; and authenticating the login user for accessing the first service system in response to the digital abstract of the authentication information of the login user being the same as one of the one or more digital abstracts stored on the blockchain according to the obtained result, whereby the first and second service systems are configured to cross-use the registered authentication information. obtaining authentication information of a login user for accessing the first service system; generating a digital abstract of the authentication information of the login user; transmitting the digital abstract of the authentication information of the login user to one or more nodes of a blockchain, wherein the blockchain is accessible to the first service system, a second service system and a storage system independent from the first and the second service systems; obtaining from the one or more nodes of the blockchain a result of a comparison between the digital abstract of the authentication information of the login user and one or more digital abstracts stored on the blockchain, wherein: the comparison is performed by the one or more nodes of the blockchain, the one or more digital abstracts comprise a digital abstract of registered authentication information of the login user for accessing the second service system, said registered authentication information comprising at least one of: i) an account identification associated with the login user; and ii) a password associated with said account identification, the one or more digital abstracts are stored on the blockchain after consensus verification by a plurality of nodes of the blockchain, and the login user is not registered with the first service system; and the comparison is performed by the one or more nodes of the blockchain, the one or more digital abstracts comprise a digital abstract of registered authentication information of the login user for accessing the second service system, said registered authentication information comprising at least one of: i) an account identification associated with the login user; and ii) a password associated with said account identification, the one or more digital abstracts are stored on the blockchain after consensus verification by a plurality of nodes of the blockchain, and the login user is not registered with the first service system; and authenticating the login user for accessing the first service system in response to the digital abstract of the authentication information of the login user being the same as one of the one or more digital abstracts stored on the blockchain according to the obtained result, whereby the first and second service systems are configured to cross-use the registered authentication information.