PuTTY (/ˈpʌti/)[4] is a free and open-source terminal emulator, serial console and network file transfer application.

It supports several network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection.

PuTTY was written and is maintained primarily by Simon Tatham, a British programmer.

PuTTY supports many variations on the secure remote terminal, and provides user control over the SSH encryption key and protocol version, alternate ciphers such as AES, 3DES, RC4, Blowfish, DES, and public-key authentication.

PuTTY uses its own format of key files – PPK (protected by Message Authentication Code).