The paper presents a new password authentication and key-exchange protocol suitable for remote user without verification table and exchanging keys over an untrusted network. The new protocol resists dictionary attacks mounted by either passive or active network intruders,even an insider attacker, allowing, in principle, even weak password phrases to be used safely. It also offers perfect forward secrecy, which protects past sessions and passwords against future compromises. Finally, user passwords are stored in a form that is not plaintext-equivalent to the password itself, so an attacker who captures the smart card cannot use it directly to compromise security and gain immediate access to the host. The proposed protocol's security, simplicity, and speed make it ideal for a wide range of real-world applications in which secure password authentication is required. Compared with the related works, the proposed scheme is more efficient and practical for distributed or portable devices.