登陆操作，用户名和密码需要传输到后台但不能直接明文显示，出于安全考虑也不应该使用对称加密，RSA是比较常见的一种做法，这里给出一个java版的完整实现，以备后用，也提供给有需要的同学。（来源来自多个博客）
maven项目，pom.xml引入
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15</artifactId>
<version>1.46</version>
</dependency>
RSA工具类代码：
package com.java.RSA;
/**
*
*/
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;
/**
*
* RSA 工具类。提供加密，解密，生成密钥对等方法。
*
*/
public class RSAUtil {
private static String RSAKeyStore = "D:"+File.separator+"RSAKey.txt";
/**
* * 生成密钥对 *
*
* @return KeyPair *
* @throws EncryptException
*
*/
public static KeyPair generateKeyPair() throws Exception {
try {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",
new org.bouncycastle.jce.provider.BouncyCastleProvider());
final int KEY_SIZE = 1024;// 没什么好说的了，这个值关系到块加密的大小，可以更改，但是不要太大，否则效率会低
keyPairGen.initialize(KEY_SIZE, new SecureRandom());
KeyPair keyPair = keyPairGen.generateKeyPair();
System.out.println(keyPair.getPrivate());
System.out.println(keyPair.getPublic());
saveKeyPair(keyPair);
return keyPair;
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
public static KeyPair getKeyPair() throws Exception {
FileInputStream fis = new FileInputStream(RSAKeyStore);
ObjectInputStream oos = new ObjectInputStream(fis);
KeyPair kp = (KeyPair) oos.readObject();
oos.close();
fis.close();
return kp;
}
public static void saveKeyPair(KeyPair kp) throws Exception {
FileOutputStream fos = new FileOutputStream(RSAKeyStore);
ObjectOutputStream oos = new ObjectOutputStream(fos);
// 生成密钥
oos.writeObject(kp);
oos.close();
fos.close();
}
/**
*
* * 生成公钥 *
*
* @param modulus
* @param publicExponent
* @return RSAPublicKey
* @throws Exception
*
*/
public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws Exception {
KeyFactory keyFac = null;
try {
keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
} catch (NoSuchAlgorithmException ex) {
throw new Exception(ex.getMessage());
}
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(modulus), new BigInteger(publicExponent));
try {
return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);
} catch (InvalidKeySpecException ex) {
throw new Exception(ex.getMessage());
}
}
/**
*
* * 生成私钥 *
*
* @param modulus
* @param privateExponent
* @return RSAPrivateKey
* @throws Exception
*
*/
public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws Exception {
KeyFactory keyFac = null;
try {
keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
} catch (NoSuchAlgorithmException ex) {
throw new Exception(ex.getMessage());
}
RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(modulus), new BigInteger(privateExponent));
try {
return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);
} catch (InvalidKeySpecException ex) {
throw new Exception(ex.getMessage());
}
}
/**
*
* * 加密 *
*
* @param key
* 加密的密钥 *
* @param data
* 待加密的明文数据 *
* @return 加密后的数据 *
* @throws Exception
*
*/
public static byte[] encrypt(PublicKey pk, byte[] data) throws Exception {
try {
Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, pk);
int blockSize = cipher.getBlockSize();// 获得加密块大小，如：加密前数据为128个byte，而key_size=1024
// 加密块大小为127
// byte,加密后为128个byte;因此共有2个加密块，第一个127
// byte第二个为1个byte
int outputSize = cipher.getOutputSize(data.length);// 获得加密块加密后块大小
int leavedSize = data.length % blockSize;
int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize;
byte[] raw = new byte[outputSize * blocksSize];
int i = 0;
while (data.length - i * blockSize > 0) {
if (data.length - i * blockSize > blockSize)
cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize);
else
cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize);
// 这里面doUpdate方法不可用，查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到
// ByteArrayOutputStream中，而最后doFinal的时候才将所有的byte[]进行加密，可是到了此时加密块大小很可能已经超出了
// OutputSize所以只好用dofinal方法。
i++;
}
return raw;
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
/**
*
* * 解密 *
*
* @param key
* 解密的密钥 *
* @param raw
* 已经加密的数据 *
* @return 解密后的明文 *
* @throws Exception
*
*/
public static byte[] decrypt(PrivateKey pk, byte[] raw) throws Exception {
try {
Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
cipher.init(cipher.DECRYPT_MODE, pk);
int blockSize = cipher.getBlockSize();
ByteArrayOutputStream bout = new ByteArrayOutputStream(64);
int j = 0;
while (raw.length - j * blockSize > 0) {
bout.write(cipher.doFinal(raw, j * blockSize, blockSize));
j++;
}
return bout.toByteArray();
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
/**
*
* * *
* @param args
* *
* @throws Exception
*
*/
public static void main(String[] args) throws Exception {
//生成公私钥，保存在RSAKeyStore对应的文件位置
RSAPublicKey rsap = (RSAPublicKey) RSAUtil.generateKeyPair().getPublic();
String test = "测试";
//加密
byte[] en_test = encrypt(getKeyPair().getPublic(), test.getBytes());
//解密
byte[] test1 = "".getBytes();
byte[] de_test = decrypt(getKeyPair().getPrivate(), en_test);
//结果为test的内容
System.out.println(new String(de_test));
}
}
后台测试方法，根据前端生成的密文解密，这里给出main函数，具体的逻辑视项目而定。
package com.java.RSA;
import java.math.BigInteger;
import java.net.URLDecoder;
public class Test {
public static void main(String[] args) throws Exception {
String pwd;
//前端传输至后台的密文，这里是我测试的数据，请改成自己测试时前端页面生成的result结果
String result = "1480ed9f7d4f8999f3b1a13f87e3c220534bbf7b7618671ff66c0d34224fca0d19d58a183f558be967cecdcb6b20a6c80b83efde59a3ea05254eff05d7038b75ee5ba4b543a427b4b3560d06d900f4c7349d166bb60a1636c5a48f4bdfface3d4e7bc8073e76b2c87ad6fd18592f87216eb014eea9ae39ae3ef1c08f0416af0e";
System.out.println("原文加密后为：");
System.out.println(result);
byte[] en_result = new BigInteger(result, 16).toByteArray();
// System.out.println("转成byte[]" + new String(en_result));
byte[] de_result = RSAUtil.decrypt(RSAUtil.getKeyPair().getPrivate(), en_result);
System.out.println("还原密文：");
System.out.println(new String(de_result));
StringBuffer sb = new StringBuffer();
sb.append(new String(de_result));
pwd = sb.reverse().toString();//字符串反转操作，因为一开始解密的结果是倒过来的
System.out.println(sb);
System.out.println("=================================");
pwd = URLDecoder.decode(pwd, "UTF-8");//
System.out.println(pwd);
}
}
前台页面代码：
<!DOCTYPE html>
<html>
<head>
<title>login</title>
<script type="text/javascript" src="js/RSA.js"></script>
<script type="text/javascript" src="js/BigInt.js"></script>
<script type="text/javascript" src="js/Barrett.js"></script>
<script type="text/javascript">
function rsalogin() {
var thisPwd = document.getElementById("password").value;
bodyRSA();
var result = encryptedString(key, encodeURIComponent(thisPwd));
//result为需要传输到后台以解密的密文，自己在复制到Test.java里测试
console.log(result);
//alert(encodeURIComponent(thisPwd)+"\r\n"+result);
//loginForm.action = "loginCHK.jsp?result=" + result;
//loginForm.submit();
}
var key;
function bodyRSA() {
setMaxDigits(130);
//10001对应的是公钥系数exponent，一长串的对应公钥指数modulus，生成RSA公私钥文件的时候记得记录，这里是我测试时的数据，你需要填上你自己的
key = new RSAKeyPair("10001", "", "8f5702529ab55b68fbd79b78103e91319466d6a2e18246d596edf03ef92dc9512f2d2b125e123becba713c0f96cd9989d90e7e6d9a935b54f24f9dc074dc17c394549e5ed2dc3a86e1850c2713323667af1ba96322891eb55b32c8d7ed5a9a0589270e58fa7f2896f48c000b906e02a57df86e5ab05b7a69855ffd2160e4f467");
}
</script>
</head>
<body>
<form method="post" name="loginForm" target=_blank>
<table border="0">
<tr>
<td>
Password:
</td>
<td>
<input type='text' name="password" id=password style='width:400px' value="my passwd" />
</td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="button" value="SUBMIT" onclick="rsalogin();" />
</td>
</tr>
</table>
</form>
</body>
</html>
页面用到的几个js文件源码，省得付积分去下载了：
Barrett.js:
// BarrettMu, a class for performing Barrett modular reduction computations in
// JavaScript.
//
// Requires BigInt.js.
//
// Copyright 2004-2005 David Shapiro.
//
// You may use, re-use, abuse, copy, and modify this code to your liking, but
// please keep this header.
//
// Thanks!
//
// Dave Shapiro
// dave@ohdave.com
function BarrettMu(m)
{
this.modulus = biCopy(m);
this.k = biHighIndex(this.modulus) + 1;
var b2k = new BigInt();
b2k.digits[2 * this.k] = 1; // b2k = b^(2k)
this.mu = 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 q1 = biDivideByRadixPower(x, this.k - 1);
var q2 = biMultiply(q1, this.mu);
var q3 = biDivideByRadixPower(q2, this.k + 1);
var r1 = biModuloByRadixPower(x, this.k + 1);
var r2term = biMultiply(q3, this.modulus);
var r2 = biModuloByRadixPower(r2term, this.k + 1);
var r = biSubtract(r1, r2);
if (r.isNeg) {
r = biAdd(r, this.bkplus1);
}
var rgtem = biCompare(r, this.modulus) >= 0;
while (rgtem) {
r = biSubtract(r, this.modulus);
rgtem = biCompare(r, this.modulus) >= 0;
}
return r;
}
function BarrettMu_multiplyMod(x, y)
{
/*
x = this.modulo(x);
y = this.modulo(y);
*/
var xy = 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 = biShiftRight(k, 1);
if (k.digits[0] == 0 && biHighIndex(k) == 0) break;
a = this.multiplyMod(a, a);
}
return result;
}
BigInt.js:
// BigInt, a suite of routines for performing multiple-precision arithmetic in
// JavaScript.
//
// Copyright 1998-2005 David Shapiro.
//
// You may use, re-use, abuse,
// copy, and modify this code to your liking, but please keep this header.
// Thanks!
//
// Dave Shapiro
// dave@ohdave.com
// IMPORTANT THING: Be sure to set maxDigits according to your precision
// needs. Use the setMaxDigits() function to do this. See comments below.
//
// Tweaked by Ian Bunning
// Alterations:
// Fix bug in function biFromHex(s) to allow
// parsing of strings of length != 0 (mod 4)
// Changes made by Dave Shapiro as of 12/30/2004:
//
// The BigInt() constructor doesn't take a string anymore. If you want to
// create a BigInt from a string, use biFromDecimal() for base-10
// representations, biFromHex() for base-16 representations, or
// biFromString() for base-2-to-36 representations.
//
// biFromArray() has been removed. Use biCopy() instead, passing a BigInt
// instead of an array.
//
// The BigInt() constructor now only constructs a zeroed-out array.
// Alternatively, if you pass <true>, it won't construct any array. See the
// biCopy() method for an example of this.
//
// Be sure to set maxDigits depending on your precision needs. The default
// zeroed-out array ZERO_ARRAY is constructed inside the setMaxDigits()
// function. So use this function to set the variable. DON'T JUST SET THE
// VALUE. USE THE FUNCTION.
//
// ZERO_ARRAY exists to hopefully speed up construction of BigInts(). By
// precalculating the zero array, we can just use slice(0) to make copies of
// it. Presumably this calls faster native code, as opposed to setting the
// elements one at a time. I have not done any timing tests to verify this
// claim.
// Max number = 10^16 - 2 = 9999999999999998;
// 2^53 = 9007199254740992;
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;
function setMaxDigits(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;
}
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;
// lr10 = 10 ^ dpl10
var lr10 = biFromNumber(1000000000000000);
function BigInt(flag)
{
if (typeof flag == "boolean" && flag == true) {
this.digits = null;
}
else {
this.digits = ZERO_ARRAY.slice(0);
}
this.isNeg = false;
}
function biFromDecimal(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 = biFromNumber(Number(s.substr(i, fgl)));
i += fgl;
while (i < s.length) {
result = biAdd(biMultiply(result, lr10),
biFromNumber(Number(s.substr(i, dpl10))));
i += dpl10;
}
result.isNeg = isNeg;
}
return result;
}
function biCopy(bi)
{
var result = new BigInt(true);
result.digits = bi.digits.slice(0);
result.isNeg = bi.isNeg;
return result;
}
function biFromNumber(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;
}
function reverseStr(s)
{
var result = "";
for (var i = s.length - 1; i > -1; --i) {
result += s.charAt(i);
}
return result;
}
var hexatrigesimalToChar = new Array(
'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'
);
function biToString(x, radix)
// 2 <= radix <= 36
{
var b = new BigInt();
b.digits[0] = radix;
var qr = biDivideModulo(x, b);
var result = hexatrigesimalToChar[qr[1].digits[0]];
while (biCompare(qr[0], bigZero) == 1) {
qr = biDivideModulo(qr[0], b);
digit = qr[1].digits[0];
result += hexatrigesimalToChar[qr[1].digits[0]];
}
return (x.isNeg ? "-" : "") + reverseStr(result);
}
function biToDecimal(x)
{
var b = new BigInt();
b.digits[0] = 10;
var qr = biDivideModulo(x, b);
var result = String(qr[1].digits[0]);
while (biCompare(qr[0], bigZero) == 1) {
qr = biDivideModulo(qr[0], b);
result += String(qr[1].digits[0]);
}
return (x.isNeg ? "-" : "") + reverseStr(result);
}
var hexToChar = new Array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f');
function digitToHex(n)
{
var mask = 0xf;
var result = "";
for (i = 0; i < 4; ++i) {
result += hexToChar[n & mask];
n >>>= 4;
}
return reverseStr(result);
}
function biToHex(x)
{
var result = "";
var n = biHighIndex(x);
for (var i = biHighIndex(x); i > -1; --i) {
result += digitToHex(x.digits[i]);
}
return result;
}
function charToHex(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;
}
function hexToDigit(s)
{
var result = 0;
var sl = Math.min(s.length, 4);
for (var i = 0; i < sl; ++i) {
result <<= 4;
result |= charToHex(s.charCodeAt(i))
}
return result;
}
function biFromHex(s)
{
var result = new BigInt();
var sl = s.length;
for (var i = sl, j = 0; i > 0; i -= 4, ++j) {
result.digits[j] = hexToDigit(s.substr(Math.max(i - 4, 0), Math.min(i, 4)));
}
return result;
}
function biFromString(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 = charToHex(c);
var biDigit = biMultiplyDigit(place, digit);
result = biAdd(result, biDigit);
place = biMultiplyDigit(place, radix);
}
result.isNeg = isNeg;
return result;
}
function biDump(b)
{
return (b.isNeg ? "-" : "") + b.digits.join(" ");
}
function biAdd(x, y)
{
var result;
if (x.isNeg != y.isNeg) {
y.isNeg = !y.isNeg;
result = 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;
}
function biSubtract(x, y)
{
var result;
if (x.isNeg != y.isNeg) {
y.isNeg = !y.isNeg;
result = 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;
}
function biHighIndex(x)
{
var result = x.digits.length - 1;
while (result > 0 && x.digits[result] == 0) --result;
return result;
}
function biNumBits(x)
{
var n = 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;
}
function biMultiply(x, y)
{
var result = new BigInt();
var c;
var n = biHighIndex(x);
var t = 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;
}
function biMultiplyDigit(x, y)
{
var n, c, uv;
result = new BigInt();
n = 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;
}
function arrayCopy(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 = new Array(0x0000, 0x8000, 0xC000, 0xE000, 0xF000, 0xF800,
0xFC00, 0xFE00, 0xFF00, 0xFF80, 0xFFC0, 0xFFE0,
0xFFF0, 0xFFF8, 0xFFFC, 0xFFFE, 0xFFFF);
function biShiftLeft(x, n)
{
var digitCount = Math.floor(n / bitsPerDigit);
var result = new BigInt();
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 = new Array(0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F,
0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF,
0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF);
function biShiftRight(x, n)
{
var digitCount = Math.floor(n / bitsPerDigit);
var result = new BigInt();
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;
}
function biMultiplyByRadixPower(x, n)
{
var result = new BigInt();
arrayCopy(x.digits, 0, result.digits, n, result.digits.length - n);
return result;
}
function biDivideByRadixPower(x, n)
{
var result = new BigInt();
arrayCopy(x.digits, n, result.digits, 0, result.digits.length - n);
return result;
}
function biModuloByRadixPower(x, n)
{
var result = new BigInt();
arrayCopy(x.digits, 0, result.digits, 0, n);
return result;
}
function biCompare(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;
}
function biDivideModulo(x, y)
{
var nb = biNumBits(x);
var tb = biNumBits(y);
var origYIsNeg = y.isNeg;
var q, r;
if (nb < tb) {
// |x| < |y|
if (x.isNeg) {
q = 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 = biCopy(x);
}
return new Array(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 = 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 = biShiftLeft(r, lambda);
nb += lambda; // Update the bit count for x.
var n = Math.ceil(nb / bitsPerDigit) - 1;
var b = biMultiplyByRadixPower(y, n - t);
while (biCompare(r, b) != -1) {
++q.digits[n - t];
r = 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 = biMultiplyByRadixPower(y, i - t - 1);
r = biSubtract(r, biMultiplyDigit(b, q.digits[i - t - 1]));
if (r.isNeg) {
r = biAdd(r, b);
--q.digits[i - t - 1];
}
}
r = 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 = biAdd(q, bigOne);
} else {
q = biSubtract(q, bigOne);
}
y = biShiftRight(y, lambda);
r = biSubtract(y, r);
}
// Check for the unbelievably stupid degenerate case of r == -0.
if (r.digits[0] == 0 && biHighIndex(r) == 0) r.isNeg = false;
return new Array(q, r);
}
function biDivide(x, y)
{
return biDivideModulo(x, y)[0];
}
function biModulo(x, y)
{
return biDivideModulo(x, y)[1];
}
function biMultiplyMod(x, y, m)
{
return biModulo(biMultiply(x, y), m);
}
function biPow(x, y)
{
var result = bigOne;
var a = x;
while (true) {
if ((y & 1) != 0) result = biMultiply(result, a);
y >>= 1;
if (y == 0) break;
a = biMultiply(a, a);
}
return result;
}
function biPowMod(x, y, m)
{
var result = bigOne;
var a = x;
var k = y;
while (true) {
if ((k.digits[0] & 1) != 0) result = biMultiplyMod(result, a, m);
k = biShiftRight(k, 1);
if (k.digits[0] == 0 && biHighIndex(k) == 0) break;
a = biMultiplyMod(a, a, m);
}
return result;
}
RSA.js:
// RSA, a suite of routines for performing RSA public-key computations in
// JavaScript.
//
// Requires BigInt.js and Barrett.js.
//
// Copyright 1998-2005 David Shapiro.
//
// You may use, re-use, abuse, copy, and modify this code to your liking, but
// please keep this header.
//
// Thanks!
//
// Dave Shapiro
// dave@ohdave.com
function RSAKeyPair(encryptionExponent, decryptionExponent, modulus)
{
this.e = biFromHex(encryptionExponent);
this.d = biFromHex(decryptionExponent);
this.m = 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 * biHighIndex(this.m);
this.radix = 16;
this.barrett = new BarrettMu(this.m);
}
function twoDigit(n)
{
return (n < 10 ? "0" : "") + String(n);
}
function encryptedString(key, s)
// Altered by Rob Saunders (rob@robsaunders.net). New routine pads the
// string after it has been converted to an array. This fixes an
// incompatibility with Flash MX's ActionScript.
{
var a = new Array();
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 ? biToHex(crypt) : biToString(crypt, key.radix);
result += text + " ";
}
return result.substring(0, result.length - 1); // Remove last space.
}
function decryptedString(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 = biFromHex(blocks[i]);
}
else {
bi = biFromString(blocks[i], key.radix);
}
block = key.barrett.powMod(bi, key.d);
for (j = 0; j <= 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;
}
追加：可能有人会遇到解密报错的问题，可能是位超出的问题，网上有个解决办法如下：
RSAUtil类里面添加如下方法：
public static byte[] hexStringToBytes(String hexString) {
if (hexString == null || hexString.equals("")) {
return null;
}
hexString = hexString.toUpperCase();
int length = hexString.length() / 2;
char[] hexChars = hexString.toCharArray();
byte[] d = new byte[length];
for (int i = 0; i < length; i++) {
int pos = i * 2;
d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
}
return d;
}
/** * Convert char to byte * @param c char * @return byte */
private static byte charToByte(char c) {
return (byte) "0123456789ABCDEF".indexOf(c);
}
测试类里面转换用上述方法，即把
byte[] en_result = new BigInteger(result, 16).toByteArray(); 改为如下：
//如果上述方法报错
//byte[] en_result = RSAUtil.hexStringToBytes(result);