Windows includes an advanced security feature called Encrypting File System (EFS). It allows users to store encrypted files and folders to protect them from unnecessary access. Other user accounts cannot access your encrypted files. This is the strongest protection in Windows that can be used to protect individual files and folders without encrypting the entire drive.
1. Right-click on the file or folder, and select Properties from the context menu.
2. In the Properties dialog, click the Advanced button on the General tab.
Step 3: Click to check the option Encrypt contents to secure data.
Decrypt files and folders: Clear the Encrypt contents to secure data check box, and then click OK.
Step 4: If prompted, select either Apply changes to this folder only or Apply changes to this folder, subfolders and files according to what you want.
When the first you encrypt a file or folder, you may be prompted to back up the file encryption key to helping avoid permanently losing access to encrypted data. Encryption will be disabled for a folder, if you compress the folder, move it to a ZIP archive, or copy to a location that does not support NTFS encryption with EFS.
Step 1: Press Win+X, hit A to open Command Prompt (Admin).
Step 2: Execute one of the following commands as needed.
To encrypt a file or foler, type in the following command, then hit Enter.
cipher /e "PATH" (Replace PATH with the full address of the file / foler including the extension.)
To encrypt the folder and other files and folders inside it, you will have to use this command,
To decrypt a single file, run the command cipher /d "full path to the file".
To decrypt a folder, type the following command: cipher / d "full path to the folder".
To decrypt a folder that contains subfolders and files, type: cipher /d / s: "full path to the folder."