The Security improvements to Windos Vista have made it Microsoft's most secure desktop operating system to date. This is good but the user will also need to supplement the security by taking extra measures to ensure even greater security. Most of these extras are including with Windows Vista such as Encryption and Bitlocker Drive Encryption. It is important to use these systems in order to improve security and ensure that if certain files are removed from the pc, they still will remain secure. Encryption is a great way to secure individual files and the way it works is with encryption algorithms. The files contents are randomized in a way that they cannot be read unless you have the original password used to encrypt the file in the first play - decryption. It is not impossible to decrypt a file without password however this requires someone to break the encryption and is not very easy. Stronger encryption methods make this much harder for someone to do and BitLocker Drive Encryption is supposed to be un-crackable.
You have the option to encrypt your files also by going through windows explorer and selecting the properties of the files or folders to be encrypted. This can only be decrypted by the user or by an administrator of the system who has access to recover encrypted files.
Other ways of encryption is by using secure protocols such as ssh instead of regular telnet as telnet sends out information in clear text and is prone to password leaks. Kerberos is used for login encryption, so that when you are logging onto the system or domain you are not sending any login data in clear text and instead are making use of strong encryption methods such as 3DES - the way kerberos works is to issue the user with a session ticket every time you login in which is encrypted by the Ticket Granting Service running on a server and then sent out the the user. This ensures that if the user logs in once, their session cannot be replicated later unless the correct procedure is applied each time and this can also help limit session times to only necessary amounts.
