DH 是 Whitfield Diffie 和 Martin Hellman 在1976年共同發(fā)明的一種秘鑰交換算法。主要用于在不安全的網(wǎng)絡(luò)上客戶端和服務(wù)端通過交換公鑰,生成一個相同的秘鑰,并將該秘鑰作為對稱加密算法的秘鑰,達到使對稱加密算法的秘鑰可以動態(tài)修改的目的。這樣便提高了數(shù)據(jù)在網(wǎng)絡(luò)上傳輸?shù)陌踩浴?/p>
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DH 總共包含四個部分,分別是:質(zhì)數(shù)原根對、公鑰、私鑰和秘鑰。
1. 客戶端和服務(wù)端使用相同的質(zhì)數(shù)原根對:P=23 和 G=5,這是秘鑰交換的必須條件。
2. 服務(wù)端生成隨機整數(shù) A = 6,并將 A 作為私鑰,使用公鑰計算公式:
公鑰 = G 的 A 次方 取余 P,等于 Math.pow(5,6) % 23,服務(wù)端的公鑰為: 8。
3. 客戶端生成隨機整數(shù) B = 7,并將 B 作為私鑰,使用公鑰計算公式:
公鑰 = G 的 B 次方 取余 P,等于 Math.pow(5,7) % 23,客戶端的公鑰為: 17。
4. 服務(wù)端用客戶端的公鑰生成秘鑰,使用秘鑰計算公式:
秘鑰 = 17 的 A 次方 取余 P,等于 Math.pow(17,6) % 23,服務(wù)端的秘鑰為: 12。
5. 客戶端用服務(wù)端的公鑰生成秘鑰,使用秘鑰計算公式:
秘鑰 = 8 的 B 次方 取余 P,等于 Math.pow(8,7) % 23,客戶端的秘鑰為: 12。
客戶端和服務(wù)端通過交換公鑰,生成了相同的秘鑰。
首先在程序需要中對INT型變量/代表取整運行,注意區(qū)分它們的不同,而%只能用于整數(shù),取余運算 5%13=5,5除以13商0余5。
java取余運算:
取余(或余數(shù))運算符用 number1 除以 number2 (把浮點數(shù)四舍五入為整數(shù)),然后只返回余數(shù)作為 result。
通常取模運算也叫取余運算,他們都遵循處罰法則,返回結(jié)果都是余數(shù);
Java中取余運算具有如下性質(zhì):對所有int數(shù)值a和所有非零int數(shù)值b滿足:(a / b ) * b + (a % b) == a;
這意味著當(dāng)取余操作返回一個非零的結(jié)果時。它與左操作數(shù)具有相同的正負(fù)符號。
package nongli;
import java.util.Calendar;
import java.util.Date;
public final class Lauar {
private static int monCyl, dayCyl, yearCyl;
private static int year, month, day;
private static boolean isLeap;
private static int[] lunarInfo = {0x04bd8, 0x04ae0, 0x0a570, 0x054d5,
0x0d260, 0x0d950, 0x16554, 0x056a0, 0x09ad0, 0x055d2, 0x04ae0,
0x0a5b6, 0x0a4d0, 0x0d250, 0x1d255, 0x0b540, 0x0d6a0, 0x0ada2,
0x095b0, 0x14977, 0x04970, 0x0a4b0, 0x0b4b5, 0x06a50, 0x06d40,
0x1ab54, 0x02b60, 0x09570, 0x052f2, 0x04970, 0x06566, 0x0d4a0,
0x0ea50, 0x06e95, 0x05ad0, 0x02b60, 0x186e3, 0x092e0, 0x1c8d7,
0x0c950, 0x0d4a0, 0x1d8a6, 0x0b550, 0x056a0, 0x1a5b4, 0x025d0,
0x092d0, 0x0d2b2, 0x0a950, 0x0b557, 0x06ca0, 0x0b550, 0x15355,
0x04da0, 0x0a5d0, 0x14573, 0x052d0, 0x0a9a8, 0x0e950, 0x06aa0,
0x0aea6, 0x0ab50, 0x04b60, 0x0aae4, 0x0a570, 0x05260, 0x0f263,
0x0d950, 0x05b57, 0x056a0, 0x096d0, 0x04dd5, 0x04ad0, 0x0a4d0,
0x0d4d4, 0x0d250, 0x0d558, 0x0b540, 0x0b5a0, 0x195a6, 0x095b0,
0x049b0, 0x0a974, 0x0a4b0, 0x0b27a, 0x06a50, 0x06d40, 0x0af46,
0x0ab60, 0x09570, 0x04af5, 0x04970, 0x064b0, 0x074a3, 0x0ea50,
0x06b58, 0x055c0, 0x0ab60, 0x096d5, 0x092e0, 0x0c960, 0x0d954,
0x0d4a0, 0x0da50, 0x07552, 0x056a0, 0x0abb7, 0x025d0, 0x092d0,
0x0cab5, 0x0a950, 0x0b4a0, 0x0baa4, 0x0ad50, 0x055d9, 0x04ba0,
0x0a5b0, 0x15176, 0x052b0, 0x0a930, 0x07954, 0x06aa0, 0x0ad50,
0x05b52, 0x04b60, 0x0a6e6, 0x0a4e0, 0x0d260, 0x0ea65, 0x0d530,
0x05aa0, 0x076a3, 0x096d0, 0x04bd7, 0x04ad0, 0x0a4d0, 0x1d0b6,
0x0d250, 0x0d520, 0x0dd45, 0x0b5a0, 0x056d0, 0x055b2, 0x049b0,
0x0a577, 0x0a4b0, 0x0aa50, 0x1b255, 0x06d20, 0x0ada0};
private static int[] solarMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31,
30, 31};
private static String[] Gan = {"甲", "乙", "丙", "丁", "戊", "己", "庚", "辛",
"壬", "癸"};
private static String[] Zhi = {"子", "丑", "寅", "卯", "辰", "巳", "午", "未",
"申", "酉", "戌", "亥"};
private static String[] Animals = {"鼠", "牛", "虎", "兔", "龍", "蛇", "馬", "羊",
"猴", "雞", "狗", "豬"};
private static int[] sTermInfo = {0, 21208, 42467, 63836, 85337, 107014,
128867, 150921, 173149, 195551, 218072, 240693, 263343, 285989,
308563, 331033, 353350, 375494, 397447, 419210, 440795, 462224,
483532, 504758};
private static String[] nStr1 = {"日", "一", "二", "三", "四", "五", "六", "七",
"八", "九", "十"};
private static String[] nStr2 = {"初", "十", "廿", "卅", " "};
private static String[] monthNong = {"正", "正", "二", "三", "四", "五", "六",
"七", "八", "九", "十", "十一", "十二"};
private static String[] yearName = {"零", "壹", "貳", "叁", "肆", "伍", "陸",
"柒", "捌", "玖"};
private Object LogFactory;
public Lauar() {
}
//====================================== 傳回農(nóng)歷 y年的總天數(shù)
private static int lYearDays(int y) {
int i;
int sum = 348; //29*12
for (i = 0x8000; i 0x8; i = 1) {
sum += (lunarInfo[y - 1900] i) == 0 ? 0 : 1; //大月+1天
}
return (sum + leapDays(y)); //+閏月的天數(shù)
}
//====================================== 傳回農(nóng)歷 y年閏月的天數(shù)
private static int leapDays(int y) {
if (leapMonth(y) != 0) {
return ((lunarInfo[y - 1900] 0x10000) == 0 ? 29 : 30);
} else {
return (0);
}
}
//====================================== 傳回農(nóng)歷 y年閏哪個月 1-12 , 沒閏傳回 0
private static int leapMonth(int y) {
return (lunarInfo[y - 1900] 0xf);
}
//====================================== 傳回農(nóng)歷 y年m月的總天數(shù)
private static int monthDays(int y, int m) {
return ((lunarInfo[y - 1900] (0x10000 m)) == 0 ? 29 : 30);
}
//====================================== 算出農(nóng)歷, 傳入日期物件, 傳回農(nóng)歷日期物件
// 該物件屬性有 .year .month .day .isLeap .yearCyl .dayCyl .monCyl
private static void Lunar1(Date objDate) {
int i, leap = 0, temp = 0;
Calendar cl = Calendar.getInstance();
cl.set(1900, 0, 31); //1900-01-31是農(nóng)歷1900年正月初一
Date baseDate = cl.getTime();
//1900-01-31是農(nóng)歷1900年正月初一
int offset = (int) ((objDate.getTime() - baseDate.getTime()) / 86400000); //天數(shù)(86400000=24*60*60*1000)
dayCyl = offset + 40; //1899-12-21是農(nóng)歷1899年臘月甲子日
monCyl = 14; //1898-10-01是農(nóng)歷甲子月
//得到年數(shù)
for (i = 1900; i 2050 offset 0; i++) {
temp = lYearDays(i); //農(nóng)歷每年天數(shù)
offset -= temp;
monCyl += 12;
}
if (offset 0) {
offset += temp;
i--;
monCyl -= 12;
}
year = i; //農(nóng)歷年份
yearCyl = i - 1864; //1864年是甲子年
leap = leapMonth(i); //閏哪個月
isLeap = false;
for (i = 1; i 13 offset 0; i++) {
//閏月
if (leap 0 i == (leap + 1) isLeap == false) {
--i;
isLeap = true;
temp = leapDays(year);
} else {
temp = monthDays(year, i);
}
//解除閏月
if (isLeap == true i == (leap + 1)) {
isLeap = false;
}
offset -= temp;
if (isLeap == false) {
monCyl++;
}
}
if (offset == 0 leap 0 i == leap + 1) {
if (isLeap) {
isLeap = false;
} else {
isLeap = true;
--i;
--monCyl;
}
}
if (offset 0) {
offset += temp;
--i;
--monCyl;
}
month = i; //農(nóng)歷月份
day = offset + 1; //農(nóng)歷天份
}
private static int getYear() {
return (year);
}
private static int getMonth() {
return (month);
}
private static int getDay() {
return (day);
}
private static int getMonCyl() {
return (monCyl);
}
private static int getYearCyl() {
return (yearCyl);
}
private static int getDayCyl() {
return (dayCyl);
}
private static boolean getIsLeap() {
return (isLeap);
}
//============================== 傳入 offset 傳回干支, 0=甲子
private static String cyclical(int num) {
return (Gan[num % 10] + Zhi[num % 12]);
}
//====================== 中文日期
private static String cDay(int d) {
String s;
switch (d) {
case 10:
s = "初十";
break;
case 20:
s = "二十";
break;
case 30:
s = "三十";
break;
default:
s = nStr2[(int) (d / 10)];//取商
s += nStr1[d % 10];//取余
}
return (s);
}
private static String cYear(int y) {
String s = " ";
int d;
while (y 0) {
d = y % 10;
y = (y - d) / 10;
s = yearName[d] + s;
}
return (s);
}
public static String getLunar(String year, String month, String day) {
Date sDObj;
String s;
int SY, SM, SD;
int sy;
SY = Integer.parseInt(year);
SM = Integer.parseInt(month);
SD = Integer.parseInt(day);
sy = (SY - 4) % 12;
Calendar cl = Calendar.getInstance();
cl.set(SY, SM - 1, SD);
sDObj = cl.getTime();
//日期
Lunar1(sDObj); //農(nóng)歷
s = "農(nóng)歷 " + "【" + Animals[sy] + "】" + cYear(getYear()) + "年" + " ";
s += (getIsLeap() ? "閏" : "") + monthNong[getMonth()] + "月"+ (monthDays(getYear(), getMonth()) == 29 ? "小" : "大");
s += cDay(getDay()) + " ";
s += cyclical(getYearCyl()) + "年" + cyclical(getMonCyl()) + "月"+ cyclical(getDayCyl()) + "日";
return s;
}
public static void main(String[] args) {
System.out.println(getLunar("1990", "8", "26"));
System.out.println(getLunar("2008", "6", "8"));
System.out.println(getLunar("2009", "4", "3"));
System.out.println(getLunar("2011", "11", "22"));
}
}