How do I Encrypt Files?

R. Kayne

Encryption changes readable files into unreadable cipher until the decryption key is supplied. Keeping sensitive files encrypted keeps your data secure even if a computer should fall into the hands of a stranger. Encrypting sensitive files also protects them from spybots should the system become infested with malware. Luckily it’s easier than ever to encrypt files with readily available software, many of which are also free.

Some encryption uses the same key for decryption.
Some encryption uses the same key for decryption.

Complex algorithms that have been developed by various authors are used to encrypt files. These encryption programs use a single password to encrypt and decrypt data, folders, and even entire disks. Other types of encryption, referred to as “public encryption,” use one key for encryption and another for decryption, where only the latter key need be private. This method is used to privatize email and instant messaging.

Users may use encryption keys to send encrypted files as email attachments.
Users may use encryption keys to send encrypted files as email attachments.

There are many open-source, free encryption programs available. Most of these programs add a shortcut to context menus, the menus that pop up when you right-click on a file. By placing a shortcut here, you can encrypt any file by simply right-clicking on the name and selecting the encryption program. You'll be prompted for a password and the file will be encrypted to this key. If this password is forgotten, the file will not be able to be decrypted later.

An entire drive containing sensitive financial documents may be encrypted.
An entire drive containing sensitive financial documents may be encrypted.

When you encrypt files, the last three letters of the file or the extension will change according to the software. For example, when using Pretty Good Privacy® (PGP) to encrypt a Microsoft Word® document, the file becomes filename.doc.pgp. If you try to open the encrypted file by double-clicking, you will be prompted for the password that was used to encrypt it. If you encrypt more than the occasional file, you might consider keeping all sensitive files in a single folder and encrypting the folder instead.

Encrypting sensitive files may help keep computer data safe from strangers.
Encrypting sensitive files may help keep computer data safe from strangers.

Encryption options typically include the choice to automatically wipe the original file after the encryption process has completed. A “wipe” is a secure way to delete a file by rewriting over it many times so that the data cannot be retrieved, even using recovery tools. Some programs will allow you to dictate how many passes the software should make to wipe the data. A minimum of eight passes is considered secure for most purposes, while government or military might use up to 20 passes or more.

Some software offers the option of adding an attribute to keep encrypted files from displaying in Windows Explorer®. It’s important to note, however, that it’s a trivial matter to turn this feature off, causing all files to display, so this option should not be relied upon. As an alternative, steganography encryption programs will encrypt and then hide files inside graphic files that will still display properly.

It is also possible to encrypt an entire drive or volume. For example, you might keep all financial programs, banking, spreadsheets and personal documents, such as wills or other critical data, on a dedicated drive. By keeping that drive encrypted when it’s not in use, you are protecting it against malicious software as well as prying eyes should someone gain access to your system. It is also possible to encrypt a drive that contains an operating system, though for most purposes this is not necessary.

If you'd like to send an encrypted file to a friend as an email attachment, you can use an encryption program to create a self-decrypting file that will not require the receiver have encryption software installed. A password will have to be supplied, however, either by phone or some other means. Self-decrypting files are not considered truly secure because the password must be conveyed to the recipient and most passwords can be easily broken using software designed for this purpose. Nevertheless, it's a good way to keep information private as it traverses the Internet, as long as the information isn't too sensitive.

Open-source, free programs used to encrypt files, folders and drives are readily available. If you would like to encrypt email, look for a public encryption program. Remember that your correspondents will also need a compatible encryption program installed.

Software is readily available to help computer users encrypt files.
Software is readily available to help computer users encrypt files.

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Discussion Comments


Hands off. These guys use the simple "security by obscurity" principle which is generally not accepted in the security branch. The security and strength of your method should only be depended on your passwords, not on keeping the method secret. When I read "self developed" encryption methods, then this stinks. These methods are usually flawed and insecure by design. Even if you use a acknowledged method, the implementation can cause insecurities.


WinGuard Pro, a free program, has a feature to encrypt files and even disable folder access with a password.


you can use winsesame. it's a good software to encrypt and password protect files and folders.


@ Submariner- I like to get software downloads from cnet. Cnet has a large assortment of windows file encryption software, including all of the freeware mentioned in this article. You can find encryption software, file erasing software, and software that securely wipes entire hard drives.

I found software on cnet that complies with military and department of defense requirements for disk clearing and sanitization. You can wipe your computer of all info when you are getting ready to sell, recycle, or dispose of your computer, preventing anyone from ever recovering the erased data.

I also like cnet because they ensure that you are not downloading any infected software. All of their software downloads are screened for spyware, viruses, and other malware. Cnet also offers consumer and editor reviews of their software downloads.


Where can I download encryption and file erasing software? I use my computer for business and I have a lot of sensitive information on my computer. I have password protection on my computer, but it only requires a password when I am signing into my desktop. I would hate to be liable for compromising sensitive data if someone ever stole my computer.


I have created new systems of encryption that may be impenetrable by anyone.

Many forms of encryptions may use a crossword puzzle type passcode encryption, a perpetual encoding passcode or other code.

These passcodes simply scramble a system into many types of digits, images and other combinations. the passcode simply restructuralizes the data from digital digit replacements into usable data digits.

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