How to Encrypt a Large File
Computers are frequently used to store sensitive information such as credit card numbers, bank account information and tax forms. Security is something most users realize is a serious concern. Operating systems such as Windows, Mac OS X and Linux include tools used to provide extra security for sensitive information. The steps needed to encrypt a file or folder vary by each system, but are generally easy enough that anyone can encrypt data.
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Instructions
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Encrypting Files in Windows XP/Vista/7
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Navigate to the folder containing the file you want to encrypt. Right-click the file and select "Properties."
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Click the "Advanced" button in the dialog box that opens. Click the "Encrypt contents to secure data" check box at the bottom of the window. In the warning box that appears, click "Encrypt the file only," if you don't want to encrypt the entire folder.
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Click "OK" to exit the folder properties and return to Windows Explorer.
Encrypting Files in Mac OS X
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Open a Finder window and go to the Applications folder, then the Utilities folder and launch the Disk Utility program.
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5
Click the "File" menu, the "New" option, then the "Blank Disk Image" command.
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Enter a name and select a location for the new disk image. Click the menu next to "Encryption" and select either "AES 128" or "256 bit."
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Click the "Volume Size" amount to change it as needed. Click the field next to "Image Format" and change the format to "sparse bundle disk image." Mac OS 10.4 users should change it to "sparse disk image."
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Click "Create" and enter a password when prompted. Mount the image like a normal installation DMG and it will appear in Finder. Drag any files you want to encrypt into the newly created disk.
Encrypting Files in Linux
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Open a terminal window.
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Use the "cd" command to move to the folder containing the file you want to encrypt. If the file is located in a folder called Documents in your home folder, you would type "cd /home/Documents." Type commands without quotes or periods.
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Type the following command to encrypt the file: "gpg -c myencryptedfile.txt." This creates a new file with a ".gpg" extension. To decrypt the file, repeat the previous steps and type the "gpg" command without the "-c" parameter.
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Tips & Warnings
If you forget your encryption password in Linux or Mac there is no way to retrieve the encrypted data.
If your certificate key file is lost or corrupted in Windows you won't be able to open the encrypted file or folder; make a backup copy that is not on your hard drive.
References
- Photo Credit computer security concept - usb cable and padlock isolated image by dinostock from Fotolia.com
