摘 要
隨著計算機和通信技術的迅猛發展，大量敏感信息通過公共通信設施或計算機網絡進行交換，特別是Internet的廣泛應用、電子商務和電子政務的迅速發展，越來越多的個人信息需要嚴格保密，如銀行賬號、個人隱私等。正是這種對信息的機密性與真實性的需求，很有必要設計一個加密軟件對其敏感信息加密。一個好的加密工具能夠讓用戶方便快捷對重要信息進行有效保護，從而大大降低了公司的重要信息泄露的安全隱患，真正做到機密信息只供有權限的用戶查閱。
本系統采用ASP.NET (C#)作為開發工具，系統主要功能包含：加密文件的密碼設置、加密文件、解密密碼的驗證、解密文件等。加密功能需要擴展的方面有：對網絡數據流加密和解密；對節點加密和節點解密；對數據打包封裝，實現網絡上使用密文傳輸；局部文本加密替換。此外，密鑰的分配必須通過安全的渠道進行傳輸，因為密鑰的管理是關系到整個加密方案的重要安全因素。
關鍵詞：DES加密器；ASP.NET (C#)；文件加密；文件解密
The Implementation of a Document Encrypter Based on C#
Abstract
With the rapid development of the computer and communication technologies， large mount of sensitive information are exchanged on the public communications facilities or computer networks. Especially under the situation of the widespread of the Internet applications， such as E-commerce and E-government， more and more information， such as bank account numbers， personal privacy， need to be encrypted. Such requirement for the secrecy and authenticity makes it necessary to develop an encrypter to encrypt the sensitive information.
This system， developed with ASP.NET (C #)， primarily includes such functions as setting the password of the document to be encrypted， encrypting the document， verifying the decryption password and decrypting the document. What needs to expand include encrypting and decrypting the network data or data on hosts; packaging data on the Internet and implementing encrypted transmission; replacing partial text in encrypted document. Besides， keys need to be transmitted on the safety channel because key management is the critical safety factor of the entire document. Users can protect their important data and prevent the unauthenticated persons from stealing the information by using the entrypter. Encryption is the key means to protect the important information， and decryption is to restore the encrypted data to make it readable.
Key words: The DES encrypter; ASP.NET ( C#); Document encryption; the Document decryption
