You can protect files and folders with Gpg4win. The software is the Windows implementation of the popular pen source encryption tool GNU Privacy Guard. It uses the asymmetrical encryption standard RSA, which uses one public and one private key. Files encrypted with your public key can be opened again with your private key only. This is why Gpg4win is ideal for encrypting files for recipients whom you don’t know personally. Gpg4win also provide email secuirty solution.
1 Setting up Gpg4win
Install Gpg4win after downloading it from our site or directly from gpg4win.org. For private use, install and use the software with your usual user account. For enhanced security requirements, you should minimise the possibility of attack by using separate Windows accounts for instance – an unprivileged one for surfing, from which the profile data of the account cannot be accessed and in which encrypted communication is possible.
2 Generating the key
After installing Gpg4win, start the key management tool Kleopatra and then start the relevant wizard by going to “File | New certificate…”. Select “Create a personal OpenPGP key pair” and enter your name and email address. Click “Next” and then enter a minimum ten digit passphrase, which contains upper case and lower case letters as well as numbers and symbols. “For example something like this = Ah2F7GkZ6l!” You can ignore the last dialog window – your will have your key pair once you click “Finish”.
3 Managing keys
You can now see your key pair in Kleopatra – this is enough for encrypting files for yourself. If you want your acquaintances or colleagues to be able to open a file, you need to add its public OpenPGP key to Kleopatra via “Import certificates”. This is also applicable to all email contacts, who need to decode the mails encrypted by you. You will have to send your public key by rightclicking your key and selecting “Export certificate”. If someone wants to encrypt the file for you, they must first import the resulting .ascfile in their Kleopatra.
4 Encrypting files
To encrypt a file or folder, right-click it in the Explorer and in the context menu, click “Sign and encrypt”. In the next dialog, select the “Sign and encrypt…” option. Then look for the public keys for encryption by clicking these in the top field and then clicking “Add”. Add your own key and then the key of the recipient. Select your own certificate as the OpenPGP signature certificate. Then enter the passphrase you have created as mentioned in point 2 and the encrypted .gpg gets generated. (Source : Chip MY)