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.Standards groups are working even as you read thisto create new methods for protecting data.Learning about the standards will saveconsiderable time.You won t have to reinvent the wheel and create everything from scratch.In addition, your security methods will mesh with those used by other developers, reducingthe user learning curve and making it possible for you to use tools developed for otherprogrammers.I could write an entire book on just security standards, so consider the information in thesections that follow just the tip of the iceberg.The standards that follow are those that you llwant to use most often to create applications today.Windows 2000 Authentication Over HTTPWindows 2000 authentication is less a programmer issue and more a network setup issue.However, you should know about authentication issues, especially if you plan to work withintranets or Internets.Windows 2000 supports two basic types of authentication.The first method of authentication is Windows 2000 Challenge/Response.This method relieson communication between the server and the client without any form of user input.Theserver asks the client to provide the username and password the user supplied during initiallogin to the system.The client provides a specially encrypted username and password.It must also supply a domain name since the client must be part of the server s domain or existin one of the trusted domains that the server recognizes.Since Windows 2000Challenge/Response automatically uses encryption to pass information between the clientand server, it s more secure than the basic authentication provided by the server.How does the client know to send the username and password to the server? The serverrequests the information as part of a header.The server sends an error message (401Access Denied) that tells the client to request secure access.It s important to realize thatwhat you see in the browser doesn t include everything that the browser actually receivesfrom the server.What you see in the browser is the information that the server wants you tosee after the browser strips off any header information.For example, the server tells thebrowser what type of information it s receiving so that the browser can activate a helperapplication if necessary.The second method relies on a digital signature technology known as SSL (Secure SocketsLayer).Windows 2000 requests a digital certificate from the client machine.The client canlikewise request a digital certificate from Windows 2000.The client and server obtain thesedigital certificates from a third-party vendor such as VeriSign.(See the Working with SSL section later in this chapter for details on how SSL works.)CautionIf you choose to implement basic security on your Internet site, you mustuse Secure Sockets Layer (SSL) to ensure secure transmission ofusername and password information.Using basic security without SSLtransmits the username and password in plain text, making it very easyfor someone to intercept the username and password and use them togain access to your secured Internet site.Using Digital SignaturesMany developers refer to digital signatures as certificates.Whichever term you use, think ofdigital signatures as you would a driver s license, since it has the same function.A digitalsignature identifies some Internet object who created it and when and could potentiallyprovide other information.If the object is a client or server, a digital signature shows thecurrent owner of that object.The digital signature, like a driver s license, also expiresforcing vendors to keep proving their identity.The expiration date also gives crackers a lotless time to figure out how to steal the certificate.(Since each certificate is a separate item,learning to steal one won t necessarily buy the cracker anything.) Using a digital signaturehelps to keep everyone honest, because it forces everyone to go through a centralverification point.A digital signature avoids the one big problem with the honor system usedby the Internet to date: it doesn t rely on one person to maintain the security of yourmachine.Of course, digital certificates aren t perfect.The VeriSign debacle (see the InfoWorld articleat http://www.infoworld.com/articles/hn/xml/01/03/22/010322hnmicroversign.xml fordetails) leaves the integrity of digital certificates in doubt.Fortunately, the release of a falsedigital certificate is still extremely unlikely.You can trust the integrity of the digital certificatein most cases.Still, it pays to provide additional security in an application that forces the userto acknowledge trust in the vendor s certificate.Implementing a digital signature especially from the client end is straightforward.In mostcases, you ll find that vendors provide a standard certificate recognized by any browser orserver with that capability, but there are some differences in the way the certificates actuallyaccomplish the task.VeriSign offers several levels of digital certificate.Make sure you getthe right level for the job at hand.Unfortunately, this information changes from time-to-time,so you ll want to visit the VeriSign site at http://www.verisign.com for details.See the Internet Component Download Mechanics section of this chapter for information on usingdigital certificates to sign your controls.KerberosKerberos is a private key protocol.This means Kerberos is limited to use between sites thatknow each other, since the sites have to agree on keys in advance.In other words, you llnormally restrict your use of Kerberos to the local network, a virtual private network (VPN),or intranet communications.NoteMicrosoft is always looking for ways to enhance the security that Windowsprovides.One of the new features for Windows 2000 is an authenticationrequirement.Windows must authenticate users before they gain access toan NTFS partition.In addition, NTFS uses the Kerberos 5 Protocol to securedata on the drive.These protection upgrades reduce the probability thatsomeone will steal data from your drive
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