臺灣博碩士論文加值系統

對稱式加密系統是應用範圍最廣的加密演算法，優點是速度快，但金鑰匙不能公開，需要有一個安全方式將金鑰匙送至對方，所以金鑰匙與密文的傳送不能在同一通道。而非對稱式加密系統的優點是金鑰匙可以公開，金鑰匙與密文的傳送可在同一通道，但速度會比對稱式加密系統慢。本論文對稱式加密是使用高階加密標準，非對稱式加密使用的是三個背包加密，它和RSA加密比起來，RSA n值的位元數至少要1500bits才是安全的，但三個背包加密用兩個非絕對遞增數列的乘積再加上一個絕對遞增數列的和，只要256bits可有效的抵抗攻擊。結合兩種加密系統的優點，利用對稱式加密的高階加密標準輸出反饋模式和計數器模式，來加密檔案大的明文，再利用非對稱式加密的三個背包加密來加密初始化向量，使得初始化向量與密文的傳送可在同通道，加強傳送的安全性。

The advantage of using symmetric encryption system is the fast encryption and decryption speed however the secret key cannot be publicized therefore we need a secure channel to transmit the secret key. The public key and private key used in asymmetric encryption system are slow but no need for key transmission. In this thesis, we have developed a secure and fast data transmission system that can take both the advantages on symmetric and asymmetric systems cryptosystem to transmit a large amount of data. The secure transmission system is combined an Advanced Encryption Standard(AES) with a symmetric key which is using Output Feedback(OFB)、Counter mode(CTR) and a Three Knapsacks Encryption(TKE) asymmetric key system. Compared to RSA cryptosystem, the RSA key needs at least 1500 bits but the TKE key needs only 256 bits. The TKE key is composed by a product of two non-superincresing knapsack and add one superincresing knapsack therefore can resist attack. A larger number of plaintext files are transmitted on this secure system and the test results show that the proposed system can have a great promise on both security and speed.

摘要 i
ABSTRACT ii
目次 iii
圖目次 v
表目次 vi
第一章 緒論 1
1.1 資料安全 1
1.2 對稱式加密 1
1.3 非對稱式加密 2
1.4 研究目的 3
第二章 AES架構與演算法 4
2.1 AES演算法概述 4
2.2 AES加密演算法 5
2.2.1 SubBytes 6
2.2.2 ShiftRows 8
2.2.3 MixColumns 8
2.2.4 AddRoundKey 8
2.3 AES解密演算法 9
2.3.1 INVSubBytes 9
2.3.2 INVShiftRows 11
2.3.3 INVMixColumns 11
2.4 OFB模式 11
2.5 CTR模式 13
第三章 三個背包加密系統 15
3.1 背包加密系統 15
3.2 金鑰匙產生 15
3.3 加密系統 18
3.4 解密系統 20
3.5 範例 22
3.6 背包的安全性 26
第四章 研究結果與比較 27
4.1 AES OFB和AES CTR模式 27
4.2 AES OFB和AES CTR加入Three Knapsacks模式 28
4.2.1 AES OFB加入Three Knapsacks模式 28
4.2.2 AES CTR加入Three Knapsacks模式 29
4.2.3 比較AES OFB和AES CTR加入Three Knapsacks模式 30
4.2.4 Three Knapsacks Load Key和Generation Key的比較 32
4.3 Encoding message size 33
第五章 結論與未來研究 35
5.1 結論 35
5.2 未來研究 35
參考文獻 36

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