Although several external hard drives integrate hardware password-protected encryption, these are rare compared to insecure drives. If yours is an open drive, you can use a software encryption program to prevent unauthorized users from accessing your data. If you have Windows 7 Ultimate or Enterprise edition, you already have one such program, called BitLocker Drive Encryption. Other Windows 7 editions must rely on third-party software, such as the free and open-source TrueCrypt program. Such open-source programs may seem less secure, because the source code and encryption algorithm are available for deconstruction, but in fact their security is strengthened by having thousands of programmers thoroughly test the code and identify potential weaknesses.
Attach your external hard drive to your Windows 7 Ultimate or Enterprise computer and power on the drive.
Click "Start | Control Panel | Security | BitLocker Drive Encryption" to open the BitLocker program.
Click "Turn On BitLocker" next to your listed external hard drive.
Check "Use a Password to Unlock the Drive" and enter a password in the "Type Your Password" and "Retype Your Password" fields, making sure the password is the same in both fields. Click "Next."
Click "Save the Recovery Key to a File," choose a save location on your main hard drive and click "Save." Alternatively, insert a USB flash drive in your USB port, click "Save the Recovery Key to a USB Flash Drive" and click "Save." Either option creates a recovery key, so you can decrypt the drive if you forget your password. Click "Next."
Click "Start Encrypting" to encrypt the drive and require a password for subsequent access. The encryption process can take several minutes --or even hours-- to complete, depending on the size of your drive and your processing power.
Attach your external hard drive and install the TrueCrypt program.
Click the "Create Volume" button in TrueCrypt.
Click "Encrypt a Non-System Partition/Drive" and then "Next." Click "Yes" if you receive a security warning; you may also need to enter the administrator password.
Click "Standard TrueCrypt Volume" and then "Next."
Click "Select Device," choose the external hard drive's partition from the list and click "OK." If the external hard drive contains multiple partitions, you have to encrypt them separately. Click "Next."
Click "Encrypt Partition in Place" if the external hard drive already contains data. If it is empty, choose "Create Encrypted Volume and Format It," which offers faster encryption. Click "Next."
Click "Next" two more times to accept the default AES encryption method
Enter a long and complex password in the "Password" and "Confirm" fields, making sure the passwords match in box fields. Click "Next."
Click "Yes" if you plan to store files larger than 4GB on the drive, or "No" if you do not foresee this need. Click "Next."
Move your mouse randomly for several seconds to strengthen the encryption key and click "Format."
Mount the drive within TrueCrypt to access it. Click "Select Drive," an available drive letter and then "Mount," and enter your password. The drive is then accessible via Windows Explorer like any other drive.
- If you forget your password and do not have a recovery key, you will be unable to access your external hard drive or its data. Be sure to write down the password and store it in a secure location, away from your external hard drive.
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