摘要
ASN.1是一種高級(jí)抽象語(yǔ)法標(biāo)記語(yǔ)言，在任何需要以數(shù)字方式發(fā)送信息的地方，ASN.1都可以發(fā)送各種形式的信息（聲頻、視頻、數(shù)據(jù)等），它以一種獨(dú)于計(jì)算機(jī)架構(gòu)和語(yǔ)言的方式來(lái)描述數(shù)據(jù)。BER是ASN.1中的基本編碼規(guī)則，它描述具體的ASN.1對(duì)象如何編碼成比特流在網(wǎng)絡(luò)上進(jìn)行傳輸，數(shù)據(jù)首先經(jīng)過(guò)BER編碼，再經(jīng)由傳輸層協(xié)議發(fā)送到接收方，接收方在相應(yīng)的端口收到數(shù)據(jù)包后，經(jīng)過(guò)BER解碼，得到具體的操作數(shù)據(jù)。本文的主要工作就是設(shè)計(jì)實(shí)現(xiàn)一個(gè)基于ASN.1 BER規(guī)約的編解碼系統(tǒng)。
本文分析比較了ASN.1定義的數(shù)據(jù)值編碼算法。開(kāi)始部分對(duì)BER編碼規(guī)則進(jìn)行比較詳細(xì)的分析，按照標(biāo)識(shí)符八位位組，長(zhǎng)度八位位組，內(nèi)容八位位組的編碼結(jié)構(gòu)，討論比較編碼的各種算法及其特點(diǎn)，并由此確定本文數(shù)據(jù)值編碼環(huán)節(jié)中所采用的編碼算法。由ASN.1 BER定義的數(shù)據(jù)值編碼的算法，設(shè)計(jì)出各種數(shù)據(jù)值編碼程序的流程圖，用C/C++程序設(shè)計(jì)語(yǔ)言，在Microsoft Visual C++ 6.0環(huán)境下編寫(xiě)編碼程序。在編寫(xiě)出完整的編碼程序后，運(yùn)行測(cè)試程序，給出相應(yīng)的數(shù)據(jù)值編碼結(jié)果截圖，驗(yàn)證編碼算法的正確性。
本文成功實(shí)現(xiàn)了一個(gè)基于ASN.1 BER規(guī)約的可視化編解碼通信系統(tǒng)。在VC(MFC)平臺(tái)下，基于已實(shí)現(xiàn)的數(shù)據(jù)值編碼模塊和解碼模塊，使用UDP協(xié)議，簡(jiǎn)單模擬兩臺(tái)計(jì)算機(jī)通過(guò)ASN.1 BER規(guī)約，編碼、傳輸、解碼數(shù)據(jù)。所設(shè)計(jì)的編解碼可視化通信系統(tǒng)，在一定程度上模擬了ASN.1在表示層的具體應(yīng)用。
關(guān)鍵詞：ASN.1，BER，編碼，算法，可視化編程


Design of Encoding and Decoding System
Based on ASN.1 BER
Abstract
ASN.1--Abstract Syntax Notation One--is a high-level language, which can send information in various forms, such as audio, video, data, etc, to anywhere that information can be sent through figures. It describes data in the way owned by computer structure and computer language. BER is the basic encoding rules of ASN.1, which describes how a specific object ASN.1 encoded bit stream for transmission on the network. The data first passes through the BER encoding, then being sent to the receiver via the transport layer protocol. The receiver receives data packets in the corresponding port, and then gets the specific operation data after BER decoding. This paper is designed to implement an encoding and decoding system based on the ASN.1 BER Statute.
This paper analyzes and compares the data value encoding algorithm defined in ASN.1. This paper first gives a detailed analysis of BER encoding rules, discussing and comparing the various algorithms encoding and characteristics in accordance with the identifier octet, octet length, content, coding structure octets. In this way, the author determines the data value encoding part of the encoding algorithm used in this paper. Design a variety of data value encoding process flow chart according to the ASN.1 BER encoded data value algorithm. Write code procedures under Microsoft Visual C + + 6.0 environment by using C / C + + programming language. Run the test program after encoding in the preparation of a complete program, and then give the results of the corresponding data value encoding capture, verifying the coding algorithm.
This paper is designed to implement a visualizing system based on ASN.1 BER Statute successfully. Based on data values that have been achieved encoding module and decoding module, this paper, using the UDP protocol in the VC (MFC) platform, demonstrates a simple simulation of two computers coding, transmission and decoding data through ASN.1 BER. The encoding and decoding visual communication system designed in this paper, to a certain extent, is a simulation of ASN.1 specific application in the presentation layer.
Keywords: ASN.1, BER, Encoding, Algorithm, Visual programming



目錄
摘要 I
Abstract II
目錄 III
第一章 緒論 1
1.1 ASN.1 BER規(guī)約概述 1
1.2 ASN.1 BER規(guī)約的應(yīng)用與發(fā)展前景 2
1.3 本文內(nèi)容和結(jié)構(gòu)安排 3
第二章 ASN.1 BER的編碼算法 4
2.1 ASN.1 BER數(shù)據(jù)值的編碼組成 4
2.1.1 標(biāo)識(shí)符八位位組 4
2.1.2 長(zhǎng)度八位位組 5
2.1.3 內(nèi)容八位位組 6
2.1.4 內(nèi)容結(jié)束八位位組 6
2.1.5 數(shù)據(jù)值編碼結(jié)果的存儲(chǔ)方式 6
2.2 布爾值 7
2.3 整數(shù)值和枚舉值 7
2.4 實(shí)數(shù)值 9
2.4.1 實(shí)數(shù)值的編碼規(guī)則 9
2.4.2 實(shí)數(shù)值的精度 10
2.4.3 實(shí)數(shù)值的編碼算法 11
2.5 位串值 12
2.6 八位位組串值 13
2.7 空值 13
2.8 結(jié)構(gòu)化值 13
2.8.1 序列值 13
2.8.2 單一序列值 14
2.8.3 集合值 14
2.8.4 單一集合值 15
2.8.5 選擇值 15
2.9 本章小結(jié) 15
第三章 基于ASN.1 BER規(guī)約的編碼實(shí)現(xiàn) 16
3.1 布爾值的編碼 16
3.2 整數(shù)值和枚舉值的編碼 17
3.3 實(shí)數(shù)值的編碼 19
3.3.1 實(shí)數(shù)值編碼分析 19
3.3.2 單精度浮點(diǎn)數(shù)編碼 21
3.3.3 雙精度浮點(diǎn)數(shù)編碼 22
3.4 位串值的編碼 23
3.5 八位位組串值的編碼 24
3.6 空值的編碼 25
3.7 結(jié)構(gòu)化編碼 27
3.7.1 序列值的編碼 27
3.7.2 單一序列值的編碼 29
3.7.3 集合值的編碼 29
3.7.4 單一集合值的編碼 30
3.8 編碼系統(tǒng) 30
3.8.1 編碼系統(tǒng)的設(shè)計(jì)說(shuō)明 30
3.8.2 編碼系統(tǒng)設(shè)計(jì)流程圖 31
3.8.3 編碼系統(tǒng)運(yùn)行結(jié)果 32
3.9 本章小結(jié) 34
第四章 基于ASN.1 BER規(guī)約的可視化編解碼系統(tǒng)及通信 35
4.1 ASN.1 BER 可視化編解碼系統(tǒng) 35
4.2 編解碼系統(tǒng)通信的實(shí)現(xiàn) 36
4.3 編解碼通信系統(tǒng)功能擴(kuò)展 39
4.4 編解碼通信系統(tǒng)測(cè)試 40
4.5 本章小結(jié) 44
第五章 總結(jié) 45
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