At this point, you may be wondering how to encrypt individual files. That’s the function of the /a switch. Using the syntax cipher /e /a <directory path\filename>, you can encrypt a single file. For example, the following command will encrypt a file named testdoc1.txt in a subdirectory named subsub within a subdirectory named subencrypted that resides in a directory named encrypted:

Cipher /e /a encrypted\subencrypted\subsub\ testdoc1.txt

You can encrypt all the files in a directory by switching to that directory and typing cipher /e /a. The command will output the results, showing you the names of the files that were encrypted. You’ll also see the warning reminder that encrypting individual files (rather than creating the files in encrypted folders) can leave remnants in plain text on the disk.

You can also use wildcards to encrypt (or decrypt) groups of files. For example, to decrypt all files in the working directory with names that begin with the letters "test," use the following command:

Cipher /d /a test*

By default, if an error occurs while Cipher is performing an encryption or decryption operation, it will stop. However, you can force the operation to continue even if errors occur by using the /i switch. The syntax is cipher /e [or /d] /i.

Normally, if there are files or folders within the path being encrypted that are already encrypted, the Cipher tool will skip the operation on those objects. However, if you want to force encryption (or decryption) of all the folders or files specified, you can use the /f switch (cipher /e [or /d] /f <directory or path>).