服务器给出的是加密后的信息、公模、指数,现在需要解密。
加密后的信息:6F07A0FF53393F619558DBD2E3EE16BC74F009D4661DB49D25A02E900EDAE56A02C142B07408E06C11E66025A42F9875ACF5FA6E5753FA5E3BF322E7284DBF1ADDB1E8F04C6FB3FBF32EA87838A6907E2A0A329B7AA1F3FC238B3B62B73C7C1AF954ED72C840CCBC49EB2538E8EA7A55C8A30A0764E2D95F59DF91D5BA6E7212
模:
93699723240557642714298223752328168207006127117803470313269635629012817131034121107145129394983372480532303750498616664968561285851237790153779524806068201674946146616076995235171678387337669517216870663016805090450941855464370990772124971064613523571889080169553919406043381049541688440844350694063503328143
指数:
52751041223791366488956578170589134293081741094930754240786067048660404059792711481594010927526534797774079972815309832166257796401533019599826805426624527321616158832674775347472860942794678504268163882233141437031764733191695179159757852053450055046188533293005499003752385892369582823636950131897518571777
解密后应为:正常的数字
服务器端代码如下:
public class RSAUtils {
/**
* 生成公钥和私钥
* @throws NoSuchAlgorithmException
*
*/
public static HashMap<String, Object> getKeys() throws NoSuchAlgorithmException{
HashMap<String, Object> map = new HashMap<String, Object>();
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
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;
}
/**
* 使用模和指数生成RSA公钥
* 注意:【此代码用了默认补位方式,为RSA/None/PKCS1Padding,不同JDK默认的补位方式可能不同,如Android默认是RSA
* /None/NoPadding】
*
* @param modulus
* 模
* @param exponent
* 指数
* @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");
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(b1, b2);
return (RSAPublicKey) keyFactory.generatePublic(keySpec);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* 使用模和指数生成RSA私钥
* 注意:【此代码用了默认补位方式,为RSA/None/PKCS1Padding,不同JDK默认的补位方式可能不同,如Android默认是RSA
* /None/NoPadding】
*
* @param modulus
* 模
* @param exponent
* 指数
* @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");
RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(b1, b2);
return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* 公钥加密
*
* @param data
* @param publicKey
* @return
* @throws Exception
*/
public static String encryptByPublicKey(String data, RSAPublicKey publicKey)
throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
// 模长
int key_len = publicKey.getModulus().bitLength() / 8;
// 加密数据长度 <= 模长-11
String[] datas = splitString(data, key_len - 11);
String mi = "";
//如果明文长度大于模长-11则要分组加密
for (String s : datas) {
mi += bcd2Str(cipher.doFinal(s.getBytes("UTF-8")));
}
return mi;
}
/**
* 私钥解密
*
* @param data
* @param privateKey
* @return
* @throws Exception
*/
public static String decryptByPrivateKey(String data, RSAPrivateKey privateKey)
throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
//模长
int key_len = privateKey.getModulus().bitLength() / 8;
byte[] bytes = data.getBytes("UTF-8");
byte[] bcd = ASCII_To_BCD(bytes, bytes.length);
System.err.println(bcd.length);
//如果密文长度大于模长则要分组解密
String ming = "";
byte[][] arrays = splitArray(bcd, key_len);
for(byte[] arr : arrays){
ming += new String(cipher.doFinal(arr));
}
return ming;
}
/**
* ASCII码转BCD码
*
*/
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转字符串
*/
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);
}
/**
* 拆分字符串
*/
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;
}
/**
*拆分数组
*/
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 {
//加密
String sysRsaPublicExponent = "65537"; //sys 公钥指数
String sysRsaModulus = "120638465331515039018602766102898243545817108824248108758756045538044335002008114706331728819795590465631377302362547268746636029891250" +
"449814559223888056676854984963129330873452309930246829596744979895825527218697094609496436664015271970577401170500785252151278453045409127914743768611747170785074707487690419"; //sys 模
RSAPublicKey publickey = RSAUtils.getPublicKey(sysRsaModulus, sysRsaPublicExponent);
String msg = RSAUtils.encryptByPublicKey("公钥加密",publickey);
System.out.println("加密后:"+msg);
//解密
String sysRsaPrivateExponent = "69691507048707743370070353001445404895625917269420837047873779453901742880754798400624368724803714772247798108968155997295384898479984467247191849129527212787744749050" +
"17092964178282019340128383046059793475544308917861326270601739489293981014213604544197641773445405470949453568565300025014058699812509971313"; //sys 私钥指数
RSAPrivateKey privateKey = RSAUtils.getPrivateKey(sysRsaModulus, sysRsaPrivateExponent);
msg = RSAUtils.decryptByPrivateKey(msg,privateKey);
System.out.println("解密后:"+msg);
}
}