SFTP (Secure File Transfer Protocol) is a network protocol that uses the Secure Shell (SSH) protocol to securely transfer files between computers.

How it works
SSH creates a secure connection when logging into a remote computer.
SFTP uses SSH to securely transfer files between a client and a remote host server.
SFTP authenticates the client and the host.
SFTP uses encryption and cryptographic hash functions to protect data integrity.

To install the SFTP follow the below steps:

Download and install OpenSSH from the GitHub (https://github.com/PowerShell/Win32-OpenSSH/releases)

1. Extract the archive to the target directory: C:\OpenSSH-Win;
2. Start the elevated PowerShell cli and switch to the OpenSSH folder: Cd C:\OpenSSH-Win
3. Add the path to the OpenSSH directory to the Path environment variable (System Properties -> Advanced tab -> Environment Variables -> Select and edit the Path system variable -> Add the path to the OpenSSH folder);
4. Install the OpenSSH server: .\install-sshd.ps1 (a green message should appear “sshd and ssh-agent services successfully installed”);

Open Command Prompt

1. Click Run as Administrator.

Use OpenSSH to Generate an SSH Key Pair

1. In the command prompt, type the following:

ssh-keygen

Now start the SSHD services by below command (from powershell)

Set-Service -Name sshd -StartupType ‘Automatic’

Start-Service sshd

Restart-Computer

Allow Port 22 from Firewall

Use the PowerShell to open TCP port 22 in the Windows Firewall for incoming SSH traffic:

New-NetFirewallRule -Protocol TCP -LocalPort 22 -Direction Inbound -Action Allow -DisplayName SSH 

Testing SFTP Connection Using WinSCP