Designing a secure and efficient authentication protocol is crucial and challenging in the mobility network. Due to the seamless roaming of mobile users over multiple foreign agents and the broadcast nature of the communication channel, the mobile networks are often exposed to several network attacks. To achieve perfect authentication and secure communication among mobility entities like MU (Mobile User), FA (Foreign Agent) and HA (Home Agent), the researchers have proposed numerous authentication protocols in the past. However, the existing protocols for the mobility environments are insufficient to address the fundamental security concerns and an adversary can impersonate the mobile user at anytime. Thus, we propose Mobile-Chain, a secure blockchain-based authentication system for mobility environments. The proposed Mobile-Chain is designed to protect user privacy and guarantees provable security like authentication, anonymity, untraceability, confidentiality, data integrity, and decentralization. The implementation of the security framework has been done on the ethereum blockchain platform using smart contracts written in a solidity programming language. The security analysis reveals that Mobile-Chain is robust against various security threats to which mobility networks are vulnerable. Besides, the authentication framework has been measured through a formal security verification tool known as Automated Validation of Internet Security Protocol and Application (AVISPA). Notably, the performance evaluation of the proposed protocol proves that it maintains performance gain, computationally efficient, and implementable in resource-limited wireless and mobility environments.