More and more users are eager to obtain more comprehensive network services without revealing their private information. Traditionally, in order to access a network, a user is authorized with an identity and corresponding keys, which are generated and managed by the network operator. All users' personally identifying information are centralized stored by the network operator. However, this approach makes users lose the control of their personally identifying information. Users are concerned about who can access these sensitive data and whether they have been compromised. In this paper, we propose a blockchain-based identity management and authentication scheme for mobile networks, where users' identifying information are controlled by the users themselves. Our scheme let users generate their self-sovereign identities (SSIs) and corresponding public keys and private keys. The private key used to authenticate the user's identifying information is only known to the user. We use blockchain to record SSIs and public keys of legitimate user, and adopt chameleon hash to delete illegal users' information on the blockchain, while keeping the block head unchanged. Furthermore, other service providers can obtain the user's SSI and public key and authenticate users by querying the blockchain. Experimental results confirm that our scheme can greatly reduce the revocation overhead and communication overhead.