本文選題：FHE　切入點：同態(tài)調用　出處：《西安電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：全同態(tài)加密,它是指在無需解密的情況下,允許對加密數(shù)據(jù)進行任意運算,將結果密文解密后得到的恰好是其明文對應的某種運算。這種同態(tài)性實現(xiàn)了在不可信終端對加密數(shù)據(jù)進行可信計算,從根本上解決了將數(shù)據(jù)及其操作委托給第三方時的保密問題。另外,全同態(tài)加密技術還在密文搜索、電子投票和多方計算等領域都有著重要的應用。自從09年Gentry提出第一個全同態(tài)加密方案至今,全同態(tài)加密機制不斷得到發(fā)展和優(yōu)化,構造出了基于不同安全假設的全同態(tài)加密體制。但其龐大的密鑰尺寸和計算復雜度使得在實際應用中效率很低。通過引入混合加密技術可以提高全同態(tài)方案的效率�；旌霞用荏w制是指將一個普通的密碼體制(對稱密碼或公鑰密碼等)和同態(tài)密碼體制結合使用,初始信息的加密使用普通密碼體制的加密算法,而解密以及對密文的運算使用同態(tài)加密體制,這樣減小了同態(tài)運算時存儲密文的代價和通信復雜度,但是這也引入了新的計算量和電路復雜度。本文在混合加密體制的背景下,研究了混合加密中同態(tài)調用普通密碼算法解密電路時消耗的同態(tài)電路層數(shù),這樣有利于我們尋找更優(yōu)的密碼算法用于混合加密。主要的工作如下:首先,對全同態(tài)加密技術的研究背景、研究現(xiàn)狀以及趨勢作出了簡單的介紹。然后,對全同態(tài)加密發(fā)展中出現(xiàn)的各種加密機制和關鍵技術進行了詳細的介紹。主要分為兩大部分:Gentry藍本的全同態(tài)加密機制和基于LWE困難問題的全同態(tài)加密機制。它們分別對應的是Gentry09方案、DGHV方案和BV11方案、BGV換模方案、Bra12模不變方案、GSW13近似特征向量法。最后,介紹了混合加密技術。總結了當前文獻中關于對稱算法AES、hash函數(shù)SHA-256,以及公鑰密碼算法ElGamal的同態(tài)調用工作。為了尋找更優(yōu)的密碼體制用于混合計算,本文利用上述同態(tài)調用的分析思路,對其他對稱算法進行了同態(tài)調用分析。主要對CLAFIA密碼和KASUMI密碼的同態(tài)計算進行了詳細的分析,得出了它們在不同編碼方式和不同的封裝情況下各自消耗的同態(tài)電路層數(shù)。另外,在比特編碼和比特封裝下,對DES等12種對稱密碼算法的同態(tài)調用進行了簡單的分析,將它們各自消耗的同態(tài)電路層數(shù)匯總成表。
[Abstract]:Full homomorphic encryption, which means that any operation of encrypted data is allowed without the need for decryption. After decrypting the result ciphertext, the result is exactly some kind of operation corresponding to its plaintext. This homomorphism realizes the trusted computation of encrypted data at untrusted terminals. It fundamentally solves the problem of confidentiality when entrusting the data and its operation to a third party. In addition, the full homomorphic encryption technology also searches the ciphertext. Electronic voting and multi-party computing have important applications. Since Gentry put forward the first full homomorphic encryption scheme in 2009, the mechanism of full homomorphic encryption has been continuously developed and optimized. A fully homomorphic encryption scheme based on different security assumptions is constructed. However, its huge key size and computational complexity make it inefficient in practical application. The effect of full homomorphism scheme can be improved by introducing mixed encryption technology. A hybrid cryptosystem is a combination of a common cryptosystem (symmetric cryptography, public key cryptography, etc.) and a homomorphic cryptosystem, The encryption of the initial information uses the common cipher encryption algorithm, while the decryption and the operation of the ciphertext use the homomorphic encryption system, which reduces the cost and communication complexity of storing the ciphertext in the homomorphic operation. However, it also introduces new computational complexity and circuit complexity. In this paper, we study the number of homomorphic circuit layers consumed when homomorphism calls the decryption circuit of common cipher algorithm in mixed encryption under the background of mixed encryption. The main work is as follows: firstly, the research background, research status and trend of the full homomorphism encryption technology are briefly introduced. Various encryption mechanisms and key technologies in the development of full homomorphic encryption are introduced in detail. They are mainly divided into two parts: one is the full homomorphic encryption mechanism of the Gentry blueprint and the other is the full homomorphic encryption mechanism based on the difficult problem of LWE. The corresponding schemes are Gentry09 scheme / DGHV scheme and BV11 scheme respectively. Bra12 mode invariant scheme / GSW13 approximate eigenvector method. This paper introduces the hybrid encryption technology, summarizes the homomorphic calls of the symmetric algorithm SHA-256 and the public key cryptosystem ElGamal in the literature. In order to find a better cryptosystem for hybrid computation, In this paper, the homomorphism call analysis of other symmetric algorithms is carried out by using the above homomorphism calls. The homomorphism calculation of CLAFIA cipher and KASUMI cipher is analyzed in detail. The number of homomorphic circuit layers consumed by them under different encoding modes and different encapsulation conditions is obtained. In addition, under bit coding and bit encapsulation, the homomorphism calls of 12 symmetric cryptographic algorithms such as DES are simply analyzed. Summarize the number of homomorphic circuit layers they consume into a table.
【學位授予單位】：西安電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN918.4

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本文編號：1585687