des加密算法實(shí)驗(yàn)報(bào)告-展示頁(yè)
2025-06-07 22:01本頁(yè)面
【正文】 DES算法由加密、子密鑰和解密的生成三部分組成。現(xiàn)將DES算法介紹如下。設(shè)該明文串為m=m1m2…m64 (mi=0或1)。其加密過程圖示如下：圖21：DES算法加密過程對(duì)DES算法加密過程圖示的說明如下：待加密的64比特明文串m，經(jīng)過IP置換（初始置換）后，得到的比特串的下標(biāo)列表如下：表21：得到的比特串的下標(biāo)列表IP58504234261810260524436282012462544638302214664564840322416857494133251791595143352719113615345372921135635547393123157該比特串被分為32位的L0和32位的R0兩部分。運(yùn)算規(guī)則為： f1與L0做不進(jìn)位的二進(jìn)制加法運(yùn)算后的結(jié)果賦給R1，R0則原封不動(dòng)的賦給L1。最后生成R16和L16。R16與L16合并成64位的比特串。R16與L16合并后成的比特串，經(jīng)過置換IP1（終結(jié)置換）后所得比特串的下標(biāo)列表如下：表22：置換后所得比特串的下標(biāo)列表IP140848165624643239747155523633138646145422623037545135321612936444125220602835343115119592734242105018582633141949175725經(jīng)過置換IP1后生成的比特串就是密文e。其過程如圖22所示：圖22：將32比特的輸入再轉(zhuǎn)化為32比特的輸出 f變換說明：輸入Ri1(32比特)經(jīng)過變換E（擴(kuò)展置換E）后，膨脹為48比特。各組經(jīng)過各自的S盒后，又變?yōu)?比特(具體過程見后)，合并后又成為32比特。見圖23：圖23在其輸入b1,b2,b3,b4,b5,b6中，計(jì)算出x=b1*2+b6, y=b5+b4*2+b3*4+b2*8，再?gòu)腟i表中查出x 行，y 列的值Sxy。（S表如圖24所示）圖24以上是DES算法加密原理五、實(shí)驗(yàn)?zāi)康模?了解DES加密算法及原理，掌握其基本應(yīng)用。七、實(shí)驗(yàn)器材（設(shè)備、元器件）：（1） PC（2） Windows （3） java程序開發(fā)環(huán)境。public class DesUtil { byte[] bytekey。 }// 聲明常量字節(jié)數(shù)組 private static final int[] IP = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 }。 // 64 private static final int[] PC_1 = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }。 // 48 private static final int[] E = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 }。 // 32 private static final int[][][] S_Box = {//S盒 {// S_Box[1] { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7 }, { 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8 }, { 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0 }, { 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 } }, { // S_Box[2] { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10 }, { 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5 }, { 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15 }, { 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 } }, {
黨政相關(guān)相關(guān)推薦
鄂ICP備17016276號(hào)-1