Tip #11: Simple File Encryption for Windows
Today's tip is on symmetric file encryption for Windows... Symmetric encryption requires only a single "key", or password, to encrypt as well as to decrypt... While this method of encryption is not as secure as asymmetric encryption (separate keys for encrypt & decrypt), if a strong passphrase is selected it is very robust... Tying into yesterday's tip, once your files are sufficiently encrypted you can safely store them on a remote server...
Windows XP provides a method of encrypting folders or drives called EFS, or Encrypted File System... This approach to encryption is tied to the currently logged on user, and as such if someone has physical access to your machine and is able to logon as your user, any encrypted files will be accessible... We'll be taking a look at something a little more secure, simple to implement, and allows transmission of the files with the encryption intact...
The utility we'll be using today is called AxCrypt... AxCrypt is a free application, is compatible with all recent versions of Windows, and uses 128-bit AES for strong and reliable encryption... The application integrates with Windows Explorer to provide a somewhat seamless approach to encrypting your data...
AxCrypt can be downloaded from here...
After you have downloaded and installed AxCrypt, you should notice that it has added a context menu in Windows Explorer... If you right-click on any file or folder, an AxCrypt menu is now available... We'll go through the process of encrypting and decrypting a file, but to further understand and explore its advanced features you should read the documentation that is installed with the application...
To encrypt an existing file, right-click on the file and select "Encrypt" from the AxCrypt context menu... This will encrypt the original file and replace it with an encrypted version... If you'd rather keep the original as is, and create a copy for archival or distribution, select "Encrypt to copy"... To create a self executing copy which can be distributed to someone who does not have or use AxCrypt, you can also select "Encrypt copy to .EXE"...
After you have selected "Encrypt" from the menu, you will be prompted to enter a passphrase to use as a key for the encryption process... The strength of the encryption is relative to the length of your passphrase, so be creative and try to use a passphrase of at least 20 characters... You will then need to verify your passphrase to ensure that you have entered it correctly... For our purposes, you can ignore the other options in this window and click "OK"...
You should now have an encrypted version of your file, which now has a filename of the original with .axx appended to it... While this is convenient to remember the name of the encrypted file, you can safely change the file name to obscure the contents of the document... When AxCrypt decrypts the file, it will revert to its original name... For example if you have a file called FinancialData.xls.axx, you can rename it to 2006BeachPhotos.axx... When decrypted the file will revert back to FinancialData.xls...
Now that we have our encrypted file, let's double-click on it to open the document... You will be prompted for the password with which it was encrypted... After entering the password, you have the option to "Remember this for decryption"... If you mark this checkbox, you will no longer need to enter a passphrase for this file, or others with the same passphrase, until you reboot or logoff... You'll appreciate this option if you created a long password... If you'd like to clear the passphrase from memory, you can right-click on a file and from the AxCrypt menu, select "Clear Passphrase memory"...
To decrypt a file back to its original self, right-click on the file and select "Decrypt" and enter your passphrase... The file will return to its original state, complete with original name...
If you have any questions, please leave a comment...
Windows XP provides a method of encrypting folders or drives called EFS, or Encrypted File System... This approach to encryption is tied to the currently logged on user, and as such if someone has physical access to your machine and is able to logon as your user, any encrypted files will be accessible... We'll be taking a look at something a little more secure, simple to implement, and allows transmission of the files with the encryption intact...
The utility we'll be using today is called AxCrypt... AxCrypt is a free application, is compatible with all recent versions of Windows, and uses 128-bit AES for strong and reliable encryption... The application integrates with Windows Explorer to provide a somewhat seamless approach to encrypting your data...
AxCrypt can be downloaded from here...
After you have downloaded and installed AxCrypt, you should notice that it has added a context menu in Windows Explorer... If you right-click on any file or folder, an AxCrypt menu is now available... We'll go through the process of encrypting and decrypting a file, but to further understand and explore its advanced features you should read the documentation that is installed with the application...
To encrypt an existing file, right-click on the file and select "Encrypt" from the AxCrypt context menu... This will encrypt the original file and replace it with an encrypted version... If you'd rather keep the original as is, and create a copy for archival or distribution, select "Encrypt to copy"... To create a self executing copy which can be distributed to someone who does not have or use AxCrypt, you can also select "Encrypt copy to .EXE"...
After you have selected "Encrypt" from the menu, you will be prompted to enter a passphrase to use as a key for the encryption process... The strength of the encryption is relative to the length of your passphrase, so be creative and try to use a passphrase of at least 20 characters... You will then need to verify your passphrase to ensure that you have entered it correctly... For our purposes, you can ignore the other options in this window and click "OK"...
You should now have an encrypted version of your file, which now has a filename of the original with .axx appended to it... While this is convenient to remember the name of the encrypted file, you can safely change the file name to obscure the contents of the document... When AxCrypt decrypts the file, it will revert to its original name... For example if you have a file called FinancialData.xls.axx, you can rename it to 2006BeachPhotos.axx... When decrypted the file will revert back to FinancialData.xls...
Now that we have our encrypted file, let's double-click on it to open the document... You will be prompted for the password with which it was encrypted... After entering the password, you have the option to "Remember this for decryption"... If you mark this checkbox, you will no longer need to enter a passphrase for this file, or others with the same passphrase, until you reboot or logoff... You'll appreciate this option if you created a long password... If you'd like to clear the passphrase from memory, you can right-click on a file and from the AxCrypt menu, select "Clear Passphrase memory"...
To decrypt a file back to its original self, right-click on the file and select "Decrypt" and enter your passphrase... The file will return to its original state, complete with original name...
If you have any questions, please leave a comment...
posted by Jameser @ 6:22 PM
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