思路：每次登入前，向後端傳送請求，由RSA生成一對公鑰和私鑰，用redis或者資料庫儲存使用者名稱對應的私鑰，獲取公鑰中的modulus和publicExponent，分別呼叫String#toString(int)方法，然後傳到前端，前端使用security.js加密密碼，然後進行登入，在後端使用私鑰解密，再驗證密碼的正確性。

注意：  - 每次登入都需要獲取公鑰和私鑰  - 保證每次登入時，生成的公鑰和私鑰與使用者名稱是對應的。

• 1.在maven專案的pom.xml中新增下面的依賴，為了引入import org.bouncycastle.jce.provider.BouncyCastleProvider;作為安全服務提供者

<dependency>
            <groupId>org.bouncycastle</groupId>
            <artifactId>bcprov-jdk16</artifactId>
            <version>1.46</version>
        </dependency>

• 2.RSAUtils工具類 

package com.zzx.sys.control;
 
import java.math.BigInteger;    
import java.security.KeyFactory;    
import java.security.KeyPair;    
import java.security.KeyPairGenerator;    
import java.security.NoSuchAlgorithmException;    
import java.security.interfaces.RSAPrivateKey;    
import java.security.interfaces.RSAPublicKey;    
import java.security.spec.RSAPrivateKeySpec;    
import java.security.spec.RSAPublicKeySpec;    
import java.util.HashMap;   
 
import javax.crypto.Cipher;   
 
import org.apache.commons.lang.StringUtils;
  
public class RSAUtils {  
	/**  
     * 生成公鑰和私鑰  
     * @throws NoSuchAlgorithmException   
     *  
     */    
    public static HashMap<String, Object> getKeys() throws NoSuchAlgorithmException{    
        HashMap<String, Object> map = new HashMap<String, Object>();    
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());    
        keyPairGen.initialize(1024);    
        KeyPair keyPair = keyPairGen.generateKeyPair();    
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();    
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();    
        map.put("public", publicKey);    
        map.put("private", privateKey);    
        return map;    
    }    
    /**  
     * 使用模和指數生成RSA公鑰  
     *   
     *   
     * @param modulus  
     *            模  
     * @param exponent  
     *            指數  
     * @return  
     */    
    public static RSAPublicKey getPublicKey(String modulus, String exponent) {    
        try {    
            BigInteger b1 = new BigInteger(modulus);    
            BigInteger b2 = new BigInteger(exponent);    
            KeyFactory keyFactory = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());    
            RSAPublicKeySpec keySpec = new RSAPublicKeySpec(b1, b2);    
            return (RSAPublicKey) keyFactory.generatePublic(keySpec);    
        } catch (Exception e) {    
            e.printStackTrace();    
            return null;    
        }    
    }    
    
    /**  
     * 使用模和指數生成RSA私鑰  
      
     * /None/NoPadding】  
     *   
     * @param modulus  
     *            模  
     * @param exponent  
     *            指數  
     * @return  
     */    
    public static RSAPrivateKey getPrivateKey(String modulus, String exponent) {    
        try {    
            BigInteger b1 = new BigInteger(modulus);    
            BigInteger b2 = new BigInteger(exponent);    
            KeyFactory keyFactory = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());    
            RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(b1, b2);    
            return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);    
        } catch (Exception e) {    
            e.printStackTrace();    
            return null;    
        }    
    }    
    
    /**  
     * 公鑰加密  
     *   
     * @param data  
     * @param publicKey  
     * @return  
     * @throws Exception  
     */    
    public static String encryptByPublicKey(String data, RSAPublicKey publicKey)    
            throws Exception {    
        Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());    
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);    
        // 模長    
        int key_len = publicKey.getModulus().bitLength() / 8;    
        // 加密資料長度 <= 模長-11    
        String[] datas = splitString(data, key_len - 11);    
        String mi = "";    
        //如果明文長度大於模長-11則要分組加密    
        for (String s : datas) {    
            mi += bcd2Str(cipher.doFinal(s.getBytes()));    
        }    
        return mi;    
    }    
    
    /**  
     * 私鑰解密  
     *   
     * @param data  
     * @param privateKey  
     * @return  
     * @throws Exception  
     */    
    public static String decryptByPrivateKey(String data, RSAPrivateKey privateKey)    
            throws Exception {    
        Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());    
        cipher.init(Cipher.DECRYPT_MODE, privateKey);    
        //模長    
        int key_len = privateKey.getModulus().bitLength() / 8;    
        byte[] bytes = data.getBytes();    
        byte[] bcd = ASCII_To_BCD(bytes, bytes.length);    
        //System.err.println(bcd.length);    
        //如果密文長度大於模長則要分組解密    
        String ming = "";    
        byte[][] arrays = splitArray(bcd, key_len);    
        for(byte[] arr : arrays){    
            ming += new String(cipher.doFinal(arr));    
        }    
        return ming;    
    }    
    /**  
     * ASCII碼轉BCD碼  
     *   
     */    
    public static byte[] ASCII_To_BCD(byte[] ascii, int asc_len) {    
        byte[] bcd = new byte[asc_len / 2];    
        int j = 0;    
        for (int i = 0; i < (asc_len + 1) / 2; i++) {    
            bcd[i] = asc_to_bcd(ascii[j++]);    
            bcd[i] = (byte) (((j >= asc_len) ? 0x00 : asc_to_bcd(ascii[j++])) + (bcd[i] << 4));    
        }    
        return bcd;    
    }    
    public static byte asc_to_bcd(byte asc) {    
        byte bcd;    
    
        if ((asc >= '0') && (asc <= '9'))    
            bcd = (byte) (asc - '0');    
        else if ((asc >= 'A') && (asc <= 'F'))    
            bcd = (byte) (asc - 'A' + 10);    
        else if ((asc >= 'a') && (asc <= 'f'))    
            bcd = (byte) (asc - 'a' + 10);    
        else    
            bcd = (byte) (asc - 48);    
        return bcd;    
    }    
    /**  
     * BCD轉字串  
     */    
    public static String bcd2Str(byte[] bytes) {    
        char temp[] = new char[bytes.length * 2], val;    
    
        for (int i = 0; i < bytes.length; i++) {    
            val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);    
            temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');    
    
            val = (char) (bytes[i] & 0x0f);    
            temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');    
        }    
        return new String(temp);    
    }    
    /**  
     * 拆分字串  
     */    
    public static String[] splitString(String string, int len) {    
        int x = string.length() / len;    
        int y = string.length() % len;    
        int z = 0;    
        if (y != 0) {    
            z = 1;    
        }    
        String[] strings = new String[x + z];    
        String str = "";    
        for (int i=0; i<x+z; i++) {    
            if (i==x+z-1 && y!=0) {    
                str = string.substring(i*len, i*len+y);    
            }else{    
                str = string.substring(i*len, i*len+len);    
            }    
            strings[i] = str;    
        }    
        return strings;    
    }    
    /**  
     *拆分陣列   
     */    
    public static byte[][] splitArray(byte[] data,int len){    
        int x = data.length / len;    
        int y = data.length % len;    
        int z = 0;    
        if(y!=0){    
            z = 1;    
        }    
        byte[][] arrays = new byte[x+z][];    
        byte[] arr;    
        for(int i=0; i<x+z; i++){    
            arr = new byte[len];    
            if(i==x+z-1 && y!=0){    
                System.arraycopy(data, i*len, arr, 0, y);    
            }else{    
                System.arraycopy(data, i*len, arr, 0, len);    
            }    
            arrays[i] = arr;    
        }    
        return arrays;    
    }  
    public static void main(String[] args) throws Exception{  
    	int i = 1;
    	i = i<<1;
    	int temp = 8;
    	System.out.println(i);
    	temp &=i;
    	System.out.println(temp);
        HashMap<String, Object> map = getKeys();    
        //生成公鑰和私鑰    
        RSAPublicKey publicKey = (RSAPublicKey) map.get("public");    
        RSAPrivateKey privateKey = (RSAPrivateKey) map.get("private");    
            
        //模    
        String modulus = publicKey.getModulus().toString();    
        System.out.println("pubkey modulus="+modulus);  
        //公鑰指數    
        String public_exponent = publicKey.getPublicExponent().toString();  
        System.out.println("pubkey exponent="+public_exponent);  
        //模 (16進位制)   
        String modulus_16 = publicKey.getModulus().toString(16);    
        System.out.println("pubkey modulus_16="+modulus_16);  
        //公鑰指數    (16進位制) 
        String public_exponent_16 = publicKey.getPublicExponent().toString(16);  
        System.out.println("pubkey exponent_16="+public_exponent_16); 
        //私鑰指數    
        String private_exponent = privateKey.getPrivateExponent().toString();    
        System.out.println("private exponent="+private_exponent);  
        //私鑰指數    (16進位制) 
        String private_exponent_16 = privateKey.getPrivateExponent().toString(16);    
        System.out.println("private exponent_16="+private_exponent_16); 
        //明文    
        String ming = "654321";    
        System.out.println(StringUtils.reverse(ming));
        //使用模和指數生成公鑰和私鑰    
        RSAPublicKey pubKey = RSAUtils.getPublicKey(modulus, public_exponent);    
        RSAPrivateKey priKey = RSAUtils.getPrivateKey(modulus, private_exponent);    
        //加密後的密文    
        String mi = RSAUtils.encryptByPublicKey(ming, pubKey);    
        System.err.println("mi="+mi); 
        //解密後的明文    
        String ming2 = RSAUtils.decryptByPrivateKey(mi, priKey);    
        System.err.println("ming2="+ming2);    
    }  
}  
 

• 3.Controller介面，為了驗證加密和解密的操作是否可行。

/**
     * 
     * @Title: generateRSAKey 
     * @Description: 生成公鑰和私鑰
     * @param username
     * @return  
     * @date 2018年2月5日 下午4:25:05
     * @author p7
     */
    @GetMapping(value = "/rsaKey/{username}")
    public ResultBean generateRSAKey(@PathVariable String username) {

        try {
            // 獲取公鑰和私鑰
            HashMap<String, Object> keys = RSAUtils.getKeys();
            RSAPublicKey publicKey = (RSAPublicKey) keys.get("public");
            RSAPrivateKey privateKey = (RSAPrivateKey) keys.get("private");
            // 儲存私鑰到 redis，也可以儲存到資料庫
            boolean res = redisService.set(username, privateKey);
            if (!res) {
                throw new BusinessLogicException("redis 儲存失敗");
            }
            // 將公鑰傳到前端
            Map<String,String> map = new HashMap<String,String>();
            // 注意返回modulus和exponent以16為基數的BigInteger的字串表示形式
            map.put("modulus", publicKey.getModulus().toString(16));
            map.put("exponent", publicKey.getPublicExponent().toString(16));

            return new ResultBean(map);
        } catch (NoSuchAlgorithmException e) {
            return new ResultBean(ResultBean.ERROR, e.getMessage());
        } catch (BusinessLogicException e) {
            return new ResultBean(ResultBean.ERROR, e.getMessage());
        }
    }

    /**
     * 
     * @Title: checkRSAKey 
     * @Description: 驗證密碼
     * @param username
     * @param password
     * @return  
     * @date 2018年2月5日 下午4:25:43
     * @author p7
     */
    @GetMapping(value = "/rsaKey/{username}/{password}")
    public ResultBean checkRSAKey(@PathVariable String username, @PathVariable String password) {
        Object object = redisService.get(username);
        try {
            // 解密
            String decryptByPrivateKey = RSAUtils.decryptByPrivateKey(password, (RSAPrivateKey) object);
            return new ResultBean(decryptByPrivateKey);
        } catch (Exception e) {
            return new ResultBean(ResultBean.ERROR, "解密失敗");
        }
    }
 

• 4.在登入頁面引入security.js 

/*
 * RSA, a suite of routines for performing RSA public-key computations in JavaScript.
 * Copyright 1998-2005 David Shapiro.
 * Dave Shapiro
 * [email protected] 
 * changed by Fuchun, 2010-05-06
 * [email protected]
 */
 
(function($w) {
 
if(typeof $w.RSAUtils === 'undefined')
    var RSAUtils = $w.RSAUtils = {};
 
var biRadixBase = 2;
var biRadixBits = 16;
var bitsPerDigit = biRadixBits;
var biRadix = 1 << 16; // = 2^16 = 65536
var biHalfRadix = biRadix >>> 1;
var biRadixSquared = biRadix * biRadix;
var maxDigitVal = biRadix - 1;
var maxInteger = 9999999999999998;
 
//maxDigits:
//Change this to accommodate your largest number size. Use setMaxDigits()
//to change it!
//
//In general, if you're working with numbers of size N bits, you'll need 2*N
//bits of storage. Each digit holds 16 bits. So, a 1024-bit key will need
//
//1024 * 2 / 16 = 128 digits of storage.
//
var maxDigits;
var ZERO_ARRAY;
var bigZero, bigOne;
 
var BigInt = $w.BigInt = function(flag) {
    if (typeof flag == "boolean" && flag == true) {
        this.digits = null;
    } else {
        this.digits = ZERO_ARRAY.slice(0);
    }
    this.isNeg = false;
};
 
RSAUtils.setMaxDigits = function(value) {
    maxDigits = value;
    ZERO_ARRAY = new Array(maxDigits);
    for (var iza = 0; iza < ZERO_ARRAY.length; iza++) ZERO_ARRAY[iza] = 0;
    bigZero = new BigInt();
    bigOne = new BigInt();
    bigOne.digits[0] = 1;
};
RSAUtils.setMaxDigits(20);
 
//The maximum number of digits in base 10 you can convert to an
//integer without JavaScript throwing up on you.
var dpl10 = 15;
 
RSAUtils.biFromNumber = function(i) {
    var result = new BigInt();
    result.isNeg = i < 0;
    i = Math.abs(i);
    var j = 0;
    while (i > 0) {
        result.digits[j++] = i & maxDigitVal;
        i = Math.floor(i / biRadix);
    }
    return result;
};
 
//lr10 = 10 ^ dpl10
var lr10 = RSAUtils.biFromNumber(1000000000000000);
 
RSAUtils.biFromDecimal = function(s) {
    var isNeg = s.charAt(0) == '-';
    var i = isNeg ? 1 : 0;
    var result;
    // Skip leading zeros.
    while (i < s.length && s.charAt(i) == '0') ++i;
    if (i == s.length) {
        result = new BigInt();
    }
    else {
        var digitCount = s.length - i;
        var fgl = digitCount % dpl10;
        if (fgl == 0) fgl = dpl10;
        result = RSAUtils.biFromNumber(Number(s.substr(i, fgl)));
        i += fgl;
        while (i < s.length) {
            result = RSAUtils.biAdd(RSAUtils.biMultiply(result, lr10),
                    RSAUtils.biFromNumber(Number(s.substr(i, dpl10))));
            i += dpl10;
        }
        result.isNeg = isNeg;
    }
    return result;
};
 
RSAUtils.biCopy = function(bi) {
    var result = new BigInt(true);
    result.digits = bi.digits.slice(0);
    result.isNeg = bi.isNeg;
    return result;
};
 
RSAUtils.reverseStr = function(s) {
    var result = "";
    for (var i = s.length - 1; i > -1; --i) {
        result += s.charAt(i);
    }
    return result;
};
 
var hexatrigesimalToChar = [
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
    'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
    'u', 'v', 'w', 'x', 'y', 'z'
];
 
RSAUtils.biToString = function(x, radix) { // 2 <= radix <= 36
    var b = new BigInt();
    b.digits[0] = radix;
    var qr = RSAUtils.biDivideModulo(x, b);
    var result = hexatrigesimalToChar[qr[1].digits[0]];
    while (RSAUtils.biCompare(qr[0], bigZero) == 1) {
        qr = RSAUtils.biDivideModulo(qr[0], b);
        digit = qr[1].digits[0];
        result += hexatrigesimalToChar[qr[1].digits[0]];
    }
    return (x.isNeg ? "-" : "") + RSAUtils.reverseStr(result);
};
 
RSAUtils.biToDecimal = function(x) {
    var b = new BigInt();
    b.digits[0] = 10;
    var qr = RSAUtils.biDivideModulo(x, b);
    var result = String(qr[1].digits[0]);
    while (RSAUtils.biCompare(qr[0], bigZero) == 1) {
        qr = RSAUtils.biDivideModulo(qr[0], b);
        result += String(qr[1].digits[0]);
    }
    return (x.isNeg ? "-" : "") + RSAUtils.reverseStr(result);
};
 
var hexToChar = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        'a', 'b', 'c', 'd', 'e', 'f'];
 
RSAUtils.digitToHex = function(n) {
    var mask = 0xf;
    var result = "";
    for (i = 0; i < 4; ++i) {
        result += hexToChar[n & mask];
        n >>>= 4;
    }
    return RSAUtils.reverseStr(result);
};
 
RSAUtils.biToHex = function(x) {
    var result = "";
    var n = RSAUtils.biHighIndex(x);
    for (var i = RSAUtils.biHighIndex(x); i > -1; --i) {
        result += RSAUtils.digitToHex(x.digits[i]);
    }
    return result;
};
 
RSAUtils.charToHex = function(c) {
    var ZERO = 48;
    var NINE = ZERO + 9;
    var littleA = 97;
    var littleZ = littleA + 25;
    var bigA = 65;
    var bigZ = 65 + 25;
    var result;
 
    if (c >= ZERO && c <= NINE) {
        result = c - ZERO;
    } else if (c >= bigA && c <= bigZ) {
        result = 10 + c - bigA;
    } else if (c >= littleA && c <= littleZ) {
        result = 10 + c - littleA;
    } else {
        result = 0;
    }
    return result;
};
 
RSAUtils.hexToDigit = function(s) {
    var result = 0;
    var sl = Math.min(s.length, 4);
    for (var i = 0; i < sl; ++i) {
        result <<= 4;
        result |= RSAUtils.charToHex(s.charCodeAt(i));
    }
    return result;
};
 
RSAUtils.biFromHex = function(s) {
    var result = new BigInt();
    var sl = s.length;
    for (var i = sl, j = 0; i > 0; i -= 4, ++j) {
        result.digits[j] = RSAUtils.hexToDigit(s.substr(Math.max(i - 4, 0), Math.min(i, 4)));
    }
    return result;
};
 
RSAUtils.biFromString = function(s, radix) {
    var isNeg = s.charAt(0) == '-';
    var istop = isNeg ? 1 : 0;
    var result = new BigInt();
    var place = new BigInt();
    place.digits[0] = 1; // radix^0
    for (var i = s.length - 1; i >= istop; i--) {
        var c = s.charCodeAt(i);
        var digit = RSAUtils.charToHex(c);
        var biDigit = RSAUtils.biMultiplyDigit(place, digit);
        result = RSAUtils.biAdd(result, biDigit);
        place = RSAUtils.biMultiplyDigit(place, radix);
    }
    result.isNeg = isNeg;
    return result;
};
 
RSAUtils.biDump = function(b) {
    return (b.isNeg ? "-" : "") + b.digits.join(" ");
};
 
RSAUtils.biAdd = function(x, y) {
    var result;
 
    if (x.isNeg != y.isNeg) {
        y.isNeg = !y.isNeg;
        result = RSAUtils.biSubtract(x, y);
        y.isNeg = !y.isNeg;
    }
    else {
        result = new BigInt();
        var c = 0;
        var n;
        for (var i = 0; i < x.digits.length; ++i) {
            n = x.digits[i] + y.digits[i] + c;
            result.digits[i] = n % biRadix;
            c = Number(n >= biRadix);
        }
        result.isNeg = x.isNeg;
    }
    return result;
};
 
RSAUtils.biSubtract = function(x, y) {
    var result;
    if (x.isNeg != y.isNeg) {
        y.isNeg = !y.isNeg;
        result = RSAUtils.biAdd(x, y);
        y.isNeg = !y.isNeg;
    } else {
        result = new BigInt();
        var n, c;
        c = 0;
        for (var i = 0; i < x.digits.length; ++i) {
            n = x.digits[i] - y.digits[i] + c;
            result.digits[i] = n % biRadix;
            // Stupid non-conforming modulus operation.
            if (result.digits[i] < 0) result.digits[i] += biRadix;
            c = 0 - Number(n < 0);
        }
        // Fix up the negative sign, if any.
        if (c == -1) {
            c = 0;
            for (var i = 0; i < x.digits.length; ++i) {
                n = 0 - result.digits[i] + c;
                result.digits[i] = n % biRadix;
                // Stupid non-conforming modulus operation.
                if (result.digits[i] < 0) result.digits[i] += biRadix;
                c = 0 - Number(n < 0);
            }
            // Result is opposite sign of arguments.
            result.isNeg = !x.isNeg;
        } else {
            // Result is same sign.
            result.isNeg = x.isNeg;
        }
    }
    return result;
};
 
RSAUtils.biHighIndex = function(x) {
    var result = x.digits.length - 1;
    while (result > 0 && x.digits[result] == 0) --result;
    return result;
};
 
RSAUtils.biNumBits = function(x) {
    var n = RSAUtils.biHighIndex(x);
    var d = x.digits[n];
    var m = (n + 1) * bitsPerDigit;
    var result;
    for (result = m; result > m - bitsPerDigit; --result) {
        if ((d & 0x8000) != 0) break;
        d <<= 1;
    }
    return result;
};
 
RSAUtils.biMultiply = function(x, y) {
    var result = new BigInt();
    var c;
    var n = RSAUtils.biHighIndex(x);
    var t = RSAUtils.biHighIndex(y);
    var u, uv, k;
 
    for (var i = 0; i <= t; ++i) {
        c = 0;
        k = i;
        for (j = 0; j <= n; ++j, ++k) {
            uv = result.digits[k] + x.digits[j] * y.digits[i] + c;
            result.digits[k] = uv & maxDigitVal;
            c = uv >>> biRadixBits;
            //c = Math.floor(uv / biRadix);
        }
        result.digits[i + n + 1] = c;
    }
    // Someone give me a logical xor, please.
    result.isNeg = x.isNeg != y.isNeg;
    return result;
};
 
RSAUtils.biMultiplyDigit = function(x, y) {
    var n, c, uv;
 
    result = new BigInt();
    n = RSAUtils.biHighIndex(x);
    c = 0;
    for (var j = 0; j <= n; ++j) {
        uv = result.digits[j] + x.digits[j] * y + c;
        result.digits[j] = uv & maxDigitVal;
        c = uv >>> biRadixBits;
        //c = Math.floor(uv / biRadix);
    }
    result.digits[1 + n] = c;
    return result;
};
 
RSAUtils.arrayCopy = function(src, srcStart, dest, destStart, n) {
    var m = Math.min(srcStart + n, src.length);
    for (var i = srcStart, j = destStart; i < m; ++i, ++j) {
        dest[j] = src[i];
    }
};
 
var highBitMasks = [0x0000, 0x8000, 0xC000, 0xE000, 0xF000, 0xF800,
        0xFC00, 0xFE00, 0xFF00, 0xFF80, 0xFFC0, 0xFFE0,
        0xFFF0, 0xFFF8, 0xFFFC, 0xFFFE, 0xFFFF];
 
RSAUtils.biShiftLeft = function(x, n) {
    var digitCount = Math.floor(n / bitsPerDigit);
    var result = new BigInt();
    RSAUtils.arrayCopy(x.digits, 0, result.digits, digitCount,
              result.digits.length - digitCount);
    var bits = n % bitsPerDigit;
    var rightBits = bitsPerDigit - bits;
    for (var i = result.digits.length - 1, i1 = i - 1; i > 0; --i, --i1) {
        result.digits[i] = ((result.digits[i] << bits) & maxDigitVal) |
                           ((result.digits[i1] & highBitMasks[bits]) >>>
                            (rightBits));
    }
    result.digits[0] = ((result.digits[i] << bits) & maxDigitVal);
    result.isNeg = x.isNeg;
    return result;
};
 
var lowBitMasks = [0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F,
        0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF,
        0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF];
 
RSAUtils.biShiftRight = function(x, n) {
    var digitCount = Math.floor(n / bitsPerDigit);
    var result = new BigInt();
    RSAUtils.arrayCopy(x.digits, digitCount, result.digits, 0,
              x.digits.length - digitCount);
    var bits = n % bitsPerDigit;
    var leftBits = bitsPerDigit - bits;
    for (var i = 0, i1 = i + 1; i < result.digits.length - 1; ++i, ++i1) {
        result.digits[i] = (result.digits[i] >>> bits) |
                           ((result.digits[i1] & lowBitMasks[bits]) << leftBits);
    }
    result.digits[result.digits.length - 1] >>>= bits;
    result.isNeg = x.isNeg;
    return result;
};
 
RSAUtils.biMultiplyByRadixPower = function(x, n) {
    var result = new BigInt();
    RSAUtils.arrayCopy(x.digits, 0, result.digits, n, result.digits.length - n);
    return result;
};
 
RSAUtils.biDivideByRadixPower = function(x, n) {
    var result = new BigInt();
    RSAUtils.arrayCopy(x.digits, n, result.digits, 0, result.digits.length - n);
    return result;
};
 
RSAUtils.biModuloByRadixPower = function(x, n) {
    var result = new BigInt();
    RSAUtils.arrayCopy(x.digits, 0, result.digits, 0, n);
    return result;
};
 
RSAUtils.biCompare = function(x, y) {
    if (x.isNeg != y.isNeg) {
        return 1 - 2 * Number(x.isNeg);
    }
    for (var i = x.digits.length - 1; i >= 0; --i) {
        if (x.digits[i] != y.digits[i]) {
            if (x.isNeg) {
                return 1 - 2 * Number(x.digits[i] > y.digits[i]);
            } else {
                return 1 - 2 * Number(x.digits[i] < y.digits[i]);
            }
        }
    }
    return 0;
};
 
RSAUtils.biDivideModulo = function(x, y) {
    var nb = RSAUtils.biNumBits(x);
    var tb = RSAUtils.biNumBits(y);
    var origYIsNeg = y.isNeg;
    var q, r;
    if (nb < tb) {
        // |x| < |y|
        if (x.isNeg) {
            q = RSAUtils.biCopy(bigOne);
            q.isNeg = !y.isNeg;
            x.isNeg = false;
            y.isNeg = false;
            r = biSubtract(y, x);
            // Restore signs, 'cause they're references.
            x.isNeg = true;
            y.isNeg = origYIsNeg;
        } else {
            q = new BigInt();
            r = RSAUtils.biCopy(x);
        }
        return [q, r];
    }
 
    q = new BigInt();
    r = x;
 
    // Normalize Y.
    var t = Math.ceil(tb / bitsPerDigit) - 1;
    var lambda = 0;
    while (y.digits[t] < biHalfRadix) {
        y = RSAUtils.biShiftLeft(y, 1);
        ++lambda;
        ++tb;
        t = Math.ceil(tb / bitsPerDigit) - 1;
    }
    // Shift r over to keep the quotient constant. We'll shift the
    // remainder back at the end.
    r = RSAUtils.biShiftLeft(r, lambda);
    nb += lambda; // Update the bit count for x.
    var n = Math.ceil(nb / bitsPerDigit) - 1;
 
    var b = RSAUtils.biMultiplyByRadixPower(y, n - t);
    while (RSAUtils.biCompare(r, b) != -1) {
        ++q.digits[n - t];
        r = RSAUtils.biSubtract(r, b);
    }
    for (var i = n; i > t; --i) {
    var ri = (i >= r.digits.length) ? 0 : r.digits[i];
    var ri1 = (i - 1 >= r.digits.length) ? 0 : r.digits[i - 1];
    var ri2 = (i - 2 >= r.digits.length) ? 0 : r.digits[i - 2];
    var yt = (t >= y.digits.length) ? 0 : y.digits[t];
    var yt1 = (t - 1 >= y.digits.length) ? 0 : y.digits[t - 1];
        if (ri == yt) {
            q.digits[i - t - 1] = maxDigitVal;
        } else {
            q.digits[i - t - 1] = Math.floor((ri * biRadix + ri1) / yt);
        }
 
        var c1 = q.digits[i - t - 1] * ((yt * biRadix) + yt1);
        var c2 = (ri * biRadixSquared) + ((ri1 * biRadix) + ri2);
        while (c1 > c2) {
            --q.digits[i - t - 1];
            c1 = q.digits[i - t - 1] * ((yt * biRadix) | yt1);
            c2 = (ri * biRadix * biRadix) + ((ri1 * biRadix) + ri2);
        }
 
        b = RSAUtils.biMultiplyByRadixPower(y, i - t - 1);
        r = RSAUtils.biSubtract(r, RSAUtils.biMultiplyDigit(b, q.digits[i - t - 1]));
        if (r.isNeg) {
            r = RSAUtils.biAdd(r, b);
            --q.digits[i - t - 1];
        }
    }
    r = RSAUtils.biShiftRight(r, lambda);
    // Fiddle with the signs and stuff to make sure that 0 <= r < y.
    q.isNeg = x.isNeg != origYIsNeg;
    if (x.isNeg) {
        if (origYIsNeg) {
            q = RSAUtils.biAdd(q, bigOne);
        } else {
            q = RSAUtils.biSubtract(q, bigOne);
        }
        y = RSAUtils.biShiftRight(y, lambda);
        r = RSAUtils.biSubtract(y, r);
    }
    // Check for the unbelievably stupid degenerate case of r == -0.
    if (r.digits[0] == 0 && RSAUtils.biHighIndex(r) == 0) r.isNeg = false;
 
    return [q, r];
};
 
RSAUtils.biDivide = function(x, y) {
    return RSAUtils.biDivideModulo(x, y)[0];
};
 
RSAUtils.biModulo = function(x, y) {
    return RSAUtils.biDivideModulo(x, y)[1];
};
 
RSAUtils.biMultiplyMod = function(x, y, m) {
    return RSAUtils.biModulo(RSAUtils.biMultiply(x, y), m);
};
 
RSAUtils.biPow = function(x, y) {
    var result = bigOne;
    var a = x;
    while (true) {
        if ((y & 1) != 0) result = RSAUtils.biMultiply(result, a);
        y >>= 1;
        if (y == 0) break;
        a = RSAUtils.biMultiply(a, a);
    }
    return result;
};
 
RSAUtils.biPowMod = function(x, y, m) {
    var result = bigOne;
    var a = x;
    var k = y;
    while (true) {
        if ((k.digits[0] & 1) != 0) result = RSAUtils.biMultiplyMod(result, a, m);
        k = RSAUtils.biShiftRight(k, 1);
        if (k.digits[0] == 0 && RSAUtils.biHighIndex(k) == 0) break;
        a = RSAUtils.biMultiplyMod(a, a, m);
    }
    return result;
};
 
 
$w.BarrettMu = function(m) {
    this.modulus = RSAUtils.biCopy(m);
    this.k = RSAUtils.biHighIndex(this.modulus) + 1;
    var b2k = new BigInt();
    b2k.digits[2 * this.k] = 1; // b2k = b^(2k)
    this.mu = RSAUtils.biDivide(b2k, this.modulus);
    this.bkplus1 = new BigInt();
    this.bkplus1.digits[this.k + 1] = 1; // bkplus1 = b^(k+1)
    this.modulo = BarrettMu_modulo;
    this.multiplyMod = BarrettMu_multiplyMod;
    this.powMod = BarrettMu_powMod;
};
 
function BarrettMu_modulo(x) {
    var $dmath = RSAUtils;
    var q1 = $dmath.biDivideByRadixPower(x, this.k - 1);
    var q2 = $dmath.biMultiply(q1, this.mu);
    var q3 = $dmath.biDivideByRadixPower(q2, this.k + 1);
    var r1 = $dmath.biModuloByRadixPower(x, this.k + 1);
    var r2term = $dmath.biMultiply(q3, this.modulus);
    var r2 = $dmath.biModuloByRadixPower(r2term, this.k + 1);
    var r = $dmath.biSubtract(r1, r2);
    if (r.isNeg) {
        r = $dmath.biAdd(r, this.bkplus1);
    }
    var rgtem = $dmath.biCompare(r, this.modulus) >= 0;
    while (rgtem) {
        r = $dmath.biSubtract(r, this.modulus);
        rgtem = $dmath.biCompare(r, this.modulus) >= 0;
    }
    return r;
}
 
function BarrettMu_multiplyMod(x, y) {
    /*
    x = this.modulo(x);
    y = this.modulo(y);
    */
    var xy = RSAUtils.biMultiply(x, y);
    return this.modulo(xy);
}
 
function BarrettMu_powMod(x, y) {
    var result = new BigInt();
    result.digits[0] = 1;
    var a = x;
    var k = y;
    while (true) {
        if ((k.digits[0] & 1) != 0) result = this.multiplyMod(result, a);
        k = RSAUtils.biShiftRight(k, 1);
        if (k.digits[0] == 0 && RSAUtils.biHighIndex(k) == 0) break;
        a = this.multiplyMod(a, a);
    }
    return result;
}
 
var RSAKeyPair = function(encryptionExponent, decryptionExponent, modulus) {
    var $dmath = RSAUtils;
    this.e = $dmath.biFromHex(encryptionExponent);
    this.d = $dmath.biFromHex(decryptionExponent);
    this.m = $dmath.biFromHex(modulus);
    // We can do two bytes per digit, so
    // chunkSize = 2 * (number of digits in modulus - 1).
    // Since biHighIndex returns the high index, not the number of digits, 1 has
    // already been subtracted.
    this.chunkSize = 2 * $dmath.biHighIndex(this.m);
    this.radix = 16;
    this.barrett = new $w.BarrettMu(this.m);
};
 
RSAUtils.getKeyPair = function(encryptionExponent, decryptionExponent, modulus) {
    return new RSAKeyPair(encryptionExponent, decryptionExponent, modulus);
};
 
if(typeof $w.twoDigit === 'undefined') {
    $w.twoDigit = function(n) {
        return (n < 10 ? "0" : "") + String(n);
    };
}
 
// Altered by Rob Saunders ([email protected]). New routine pads the
// string after it has been converted to an array. This fixes an
// incompatibility with Flash MX's ActionScript.
RSAUtils.encryptedString = function(key, s) {
    var a = [];
    var sl = s.length;
    var i = 0;
    while (i < sl) {
        a[i] = s.charCodeAt(i);
        i++;
    }
 
    while (a.length % key.chunkSize != 0) {
        a[i++] = 0;
    }
 
    var al = a.length;
    var result = "";
    var j, k, block;
    for (i = 0; i < al; i += key.chunkSize) {
        block = new BigInt();
        j = 0;
        for (k = i; k < i + key.chunkSize; ++j) {
            block.digits[j] = a[k++];
            block.digits[j] += a[k++] << 8;
        }
        var crypt = key.barrett.powMod(block, key.e);
        var text = key.radix == 16 ? RSAUtils.biToHex(crypt) : RSAUtils.biToString(crypt, key.radix);
        result += text + " ";
    }
    return result.substring(0, result.length - 1); // Remove last space.
};
 
RSAUtils.decryptedString = function(key, s) {
    var blocks = s.split(" ");
    var result = "";
    var i, j, block;
    for (i = 0; i < blocks.length; ++i) {
        var bi;
        if (key.radix == 16) {
            bi = RSAUtils.biFromHex(blocks[i]);
        }
        else {
            bi = RSAUtils.biFromString(blocks[i], key.radix);
        }
        block = key.barrett.powMod(bi, key.d);
        for (j = 0; j <= RSAUtils.biHighIndex(block); ++j) {
            result += String.fromCharCode(block.digits[j] & 255,
                                          block.digits[j] >> 8);
        }
    }
    // Remove trailing null, if any.
    if (result.charCodeAt(result.length - 1) == 0) {
        result = result.substring(0, result.length - 1);
    }
    return result;
};
 
RSAUtils.setMaxDigits(130);
 
})(window);

• 5.在登入的js中對接介面。

$(document).ready(function() {
    $(".loginBtn").click(function() {
        var uName = $(".userName").val(); //獲取使用者名稱
        var pWord = $(".passWord").val(); //獲取賬號
        // 獲取
        $.ajax({
            type:"get",
            url:userBasePath+"rsaKey/"+uName,
            success:function(data){
                console.log(data);
                var pwdKey = new RSAUtils.getKeyPair(data.data.exponent,"",data.data.modulus);
                var reversedPwd = pWord.split("").reverse().join("");
                var encrypedPwd = RSAUtils.encryptedString(pwdKey,reversedPwd);
                console.log(encrypedPwd);
                $.ajax({
                    type:"get",
                    url:userBasePath+"rsaKey/"+uName+"/"+encrypedPwd,
                    success:function(data){
                        console.log(data);
                    },
                    error: function(result, status, xhr) {
                    }
                });
            },
            error: function(result, status, xhr) {
            }
        });
    }   
}