Encrypting File System (EFS) is a feature of Windows that you can use to store information on your hard disk in an encrypted format. It uses sha1 algorithm for encryption/Decryption.

Encrypting a File

Suppose you want to encrypt a file Bank details. Right click on it and Select Properties then click on Advanced Settings.

Tick ‘Encrypt contents to secure data’ and Click ok. After That Click on Apply.

A dialog box will appear. Tick Encrypt the File only and Click OK to encrypt the File.

Now your file name font color will turn green which ensures File is encrypted successfully.

Now if you run this file on another system it will show an error Access is denied.

Decrypting a File

Now in order to decrypt that file on another system you need to create a certificate from the system by which you encrypted the file and then install that certificate on the system in which you want to run that file.

In order to create a certificate, go to file properties then advanced Attributes then details.

Click on Backup keys.

A dialog box will appear like this. Click on Next

Now Select “Include all certificates” and “Export all extended properties”. Click next.

Choose a password to protect your private key.

Select the path to which you want to store the key.

Click on Finish.

Now copy the certificate in the target system and execute it. A similar dialog Box will appear. Click on next until you see something like this. Enter the password you used before.

Click next and finish..Now the certificate is installed you can simply double click the file to open it