© ExplorNet’s Centers for Quality Teaching and Learning 1 Explain the importance of security and encryption. Objective Course Weight 2%

© ExplorNet’s Centers for Quality Teaching and Learning 2 Security Through Encryption Encryption is the process through which the contents of files and folders are secured from unauthorized access.  Contents are scrambled using keys, certificates, and algorithms.  Can only be read by an authorized user who has the proper key.

© ExplorNet’s Centers for Quality Teaching and Learning 3 Encryption in Windows Encrypting File System (EFS)  A Windows file system feature that allows users to encrypt information on all types of physical media.  Available on all versions of Windows 7.  Fully supported in the Professional, Enterprise, and Ultimate versions.  Partially supported on Starter, Home.

© ExplorNet’s Centers for Quality Teaching and Learning 4 Encryption in Windows  Files are not encrypted by default.  When users choose to encrypt the file/folder appears green in Windows Explorer.

© ExplorNet’s Centers for Quality Teaching and Learning 5 How to Use EFS  A user chooses to secure a file/folder with EFS through the Properties dialog box.

© ExplorNet’s Centers for Quality Teaching and Learning 6 How to Use EFS  From the Advanced attributes a user can choose to encrypt.  If “file only” encryption is done a second prompt asking to encrypt the folder may appear.

© ExplorNet’s Centers for Quality Teaching and Learning 7 How EFS Works: Encryption 1.When you mark a file for encryption EFS creates an encryption key.  A key is a large, random number specific to that file/folder.  The encryption key is stored with the file. 2.EFS then uses the key and an algorithm to scramble the contents of the file.  To authorized users the file appears normal.  Unauthorized attempts to open the file result in an “Access Denied” message.

© ExplorNet’s Centers for Quality Teaching and Learning 8 How EFS Works: Encryption 3.To link the key to your user account each file/folder key is encrypted with a personal file encryption certificate called an EFS Certificate. 4.Your EFS Certificate is stored in the Windows Certificate database.

© ExplorNet’s Centers for Quality Teaching and Learning 9 How EFS Works: Decryption When you attempt to open an encrypted file this is approximately what happens. 1.The file signals the need to be decoded.  To decode the file the encryption key is needed.  The encryption is stored with the file, but….  Recall that the encryption key itself was encrypted 2.The OS calls for an EFS Certificate to decode the encryption key.

© ExplorNet’s Centers for Quality Teaching and Learning 10 How EFS Works: Decryption 3.Windows finds your EFS Certificate because you are logged in to your user account.  Because your EFS Certificate was used to encrypt the file’s encryption key it can also be used to correctly decode the encryption key. 4.The OS decodes the file’s encryption key using your EFS Certificate. 5.The OS uses the file’s encryption key to decode the file.

© ExplorNet’s Centers for Quality Teaching and Learning 11 EFS Tips  Loss or damage to an encryption key or EFS Certificate means loss of the file/folder.  Always have backups.  The Administrator account is the designated recovery agent if you ever lose access to a file.  Encrypting at the folder level is preferred.  New files added to the folder are automatically encrypted.  Less chance of accidental file security breach.  Encrypting adds processing time to file accesses and increases file size significantly.

© ExplorNet’s Centers for Quality Teaching and Learning 12 BitLocker Drive Encryption  Encryption feature in the Enterprise and Ultimate versions of Windows 7 that works with TPM to secure entire disks instead of files.  Trusted Platform Module (TPM)  A microchip on many motherboards that helps protect the computer from being accessed if stolen, lost, or attacked. It works most effectively when paired with another system, like an OS.

© ExplorNet’s Centers for Quality Teaching and Learning 13 BitLocker To Go  Usually BitLocker is used to encrypt hard disk drives.  BitLocker To Go allows the encryption of portable media.

© ExplorNet’s Centers for Quality Teaching and Learning 14 Compression The process of reducing the size of data without affecting the content.  Compression is used by any company with a sizeable amount of data.  Storage is expensive.  If the data is important there will be a backup copy.  Now you need twice as much storage.

© ExplorNet’s Centers for Quality Teaching and Learning 15 Compression  Files often consist of repetitive binary patterns.  Mathematicians use this fact to develop compression algorithms that replace the repetitive data with pointers.  Pointers take up much less space without compromising the data.

© ExplorNet’s Centers for Quality Teaching and Learning 16 How to Use Compression Choose

© ExplorNet’s Centers for Quality Teaching and Learning 17 Compression Tips  Compressed files appear blue in Explorer.  Compressed files cannot be encrypted.  If you want to encrypt, decompress first, then encrypt.  Different files have different compression ratios.  Large, contiguous files usually experience the most gain from compression.  Video is a good example, lots of repeated frames.