tailieunhanh - o reilly Web Security & Commerce phần 7

cho phép các phím nhỏ như 1 bit hoặc là miễn là 2048. Khác hơn so với thực tế này và thực tế rằng cả hai đều là các thuật toán mã hóa đối xứng, hai thuật toán đã không có sự giống nhau: RC2 là một thuật toán mã hóa khối, trong khi RC4 là một mật mã dòng. | Securing Windows NT 2000 Servers for the Internet Another advantage of rcp is that you can use a .rhost file which allows you to perform authentication based on IP addresses. Although this makes your computer vulnerable to IP spoofing an attack that happens when one computer sends out IP packets that claim to be from another the risk of password sniffing is considerably greater. There is only one widely publicized case in which IP spoofing was used to break into a computer while there are literally thousands of recorded instances in which password sniffers were used by crackers to break into systems. Furthermore you can configure your network s routers to automatically reject incoming IP packets that claim to be from your internal network greatly improving your site s resistance to IP spoofing attacks. Of course this doesn t help you if the web server is out on the Internet. Using a distributed file system such as NFS to provide content to your web server is an intriguing idea. You can have the web server mount the NFS file system read-only. The NFS server should likewise export the file system read-only and it should only export the file system that contains web server files. The advantage of this system is that it gives you an easy way to update the web server s content without actually logging in to the web server. Another advantage is that you can have multiple web servers access the same NFS file system. The primary disadvantage of using a read-only NFS file system to provide files to your web server is that there are significant performance penalties using NFS. This may not be an issue with new generations of web servers that read the entire document directory into memory and then serve the web documents out of a cache. The speed of NFS is also not a factor for web pages that are programmatically generated the overhead of the CGI scripts far outweighs the overhead of NFS. Transferring the files using physical media is very attractive. No network capable .