tailieunhanh - Bảo mật hệ thống mạng part 33

Tất cả chúng ta cần phải được mã hóa an toàn là tốt và điều đó sẽ chăm sóc của tất cả mọi thứ. Đó là điệp khúc được sử dụng để được lắng nghe. Nếu thông tin được bảo vệ bằng mật mã, sau đó không ai có thể xem hoặc chỉnh sửa nó. Nếu chúng tôi sử dụng mã hóa, chúng ta biết người mà chúng ta đang nói tới vì vậy chúng tôi đã chứng thực là tốt. | CHAPTER 12 Encryption Copyright 2001 The McGraw-Hill Companies Inc. Click Here for Terms of Use. 207 208 Network Security A Beginner s Guide All we need to be secure is good encryption and that will take care of everything. That is the refrain that used to be heard. If the information is protected by encryption then no one can see it or modify it. If we use encryption we know whom we are talking to so we have authentication as well. As with everything if it sounds too good to be true it usually is. That is the case with encryption as well. Encryption is certainly an important security tool. Encryption mechanisms can help protect the confidentiality and integrity of information. Encryption mechanisms can help identify the source of information. But encryption by itself is not the answer. Encryption mechanisms can and should be a part of a comprehensive security program. In fact encryption mechanisms are probably the most widely used security mechanisms just because they can help with confidentiality integrity and accountability. However encryption is only a delaying action. We know that any encryption system can be broken. It is just that the length of time and the resources required to gain access to the information being protected by the encryption are both significant. Thus the attacker may try some other weakness in the overall system. This chapter is intended to provide you with a basic understanding of what encryption is and how it can be used. We will not be talking about the underlying mathematical theory not much anyway so you will not need an advanced degree in calculus. But we will use some examples so you understand how the various encryption algorithms can be used in a good security program. ENCRYPTION CONCEPTS Encryption is simply the obfuscation of information in such a way as to hide it from unauthorized individuals while allowing authorized individuals to see it. Individuals are defined as authorized if they have the appropriate key to decrypt the .