PuTTY is a free, open-source client program for the SSH, Telnet, Rlogin, and SUPDUP network protocols, enabling users to run remote sessions on computers over a network. It is primarily developed and maintained by Simon Tatham. PuTTY is available for Windows and Unix platforms and includes an `xterm` terminal emulator. The latest version, 0.83, was released on February 8, 2025. Key Features and Functionality: - Protocol Support: PuTTY supports multiple network protocols, including SSH, Telnet, Rlogin, and SUPDUP, allowing secure and flexible remote connections. - Cross-Platform Availability: Compatible with both Windows and Unix systems, PuTTY provides a consistent user experience across different operating environments. - Terminal Emulation: It includes an `xterm` terminal emulator, facilitating the execution of terminal-based applications on remote systems. - Security Enhancements: The latest release, version 0.83, introduces support for ML-KEM, a NIST-standardized post-quantum key exchange mechanism, enhancing security against potential future quantum computing threats. - Unicode Support: Improved Unicode support allows for the use of characters outside the Windows system code page, accommodating a broader range of languages and symbols. Primary Value and User Solutions: PuTTY addresses the need for secure, reliable, and versatile remote access to computers over a network. By supporting multiple protocols and platforms, it enables users to manage and interact with remote systems efficiently. The inclusion of advanced security features, such as post-quantum key exchange mechanisms, ensures that users' connections remain protected against evolving cybersecurity threats. Additionally, its improved Unicode support enhances usability for a global user base, accommodating diverse linguistic requirements.