import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
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;
/**
* RSA加密工具
* Created by hyq on 2018/5/4
*/
public class RSAUtil {
/**
* 生成公钥和私钥
*
* @throws NoSuchAlgorithmException
*/
public static HashMap getKeys() throws NoSuchAlgorithmException {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
HashMap map = new HashMap();
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;
}
/**
* 使用模和指数生成RSA公钥
*
* @param modulus 模
* @param exponent 指数
*/
public static RSAPublicKey getPublicKey(String modulus, String exponent) {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
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;
}
}
/**
* 使用模和指数生成RSA私钥
* /None/NoPadding
*
* @param modulus 模
* @param exponent 指数
* @return
*/
public static RSAPrivateKey getPrivateKey(String modulus, String exponent) {
try {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
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;
}
}
/**
* 公钥加密
*
* @param data
* @param publicKey
* @return
* @throws Exception
*/
public static String encryptByPublicKey(String data, RSAPublicKey publicKey) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
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()));
}
return mi;
}
/**
* 私钥解密
*
* @param data
* @param privateKey
* @return
* @throws Exception
*/
public static String decryptByPrivateKey(String data, RSAPrivateKey privateKey) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());
cipher.init(Cipher.DECRYPT_MODE, privateKey);
//模长
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 {
HashMap map = getKeys();
//生成公钥和私钥
RSAPublicKey publicKey = (RSAPublicKey) map.get("public");
RSAPrivateKey privateKey = (RSAPrivateKey) map.get("private");
//模
String modulus = publicKey.getModulus().toString();
modulus = "dd6be3d4de56287b8c3616b33bc1b7a5a2bb9148252140262420ee047f83b3165fb7674a759d60c24b71fd5437c7810f127f2c4370c2d4bdfcb55c08f1b3c715b7b2f57228e78e34039d2b967f54a58e345bc91e3dd54c7bea86d73c9e2de968736bf2b97f50bea891aa3519ae7238d76dff57cabba7cc0d370775657f3b5c83";
BigInteger sixthtest2 = new BigInteger(modulus, 16);
modulus = sixthtest2.toString();
System.out.println("pubkey modulus=" + modulus);
//公钥指数
String public_exponent = publicKey.getPublicExponent().toString();
public_exponent = "10001";
BigInteger hh = new BigInteger(public_exponent, 16);
public_exponent = hh.toString();
System.out.println("pubkey exponent=" + public_exponent);
// //私钥指数
String private_exponent = privateKey.getPrivateExponent().toString();
private_exponent = "54712537089112817889981994641184352849048377286188637988954612170120627468763880489886706964032019663270893057329335059472175306012819568365723658387355119672809485653603643981222096667941140888521671620447127553757093714372635754674996604605878456428149342380671195977042995355568862882828346936935942070657";
System.out.println("private exponent=" + private_exponent);
//明文
String ming = "147690";
//使用模和指数生成公钥和私钥
RSAPublicKey pubKey = RSAUtil.getPublicKey(modulus, public_exponent);
RSAPrivateKey priKey = RSAUtil.getPrivateKey(modulus, private_exponent);
//加密后的密文
String mi = RSAUtil.encryptByPublicKey(ming, pubKey);
System.err.println("mi=" + mi);
// //解密后的明文
String ming2 = RSAUtil.decryptByPrivateKey(mi, priKey);
System.err.println("ming2=" + ming2);
// System.out.println("=====================================进制转换===========================");
// String name="dd6be3d4de56287b8c3616b33bc1b7a5a2bb9148252140262420ee047f83b3165fb7674a759d60c24b71fd5437c7810f127f2c4370c2d4bdfcb55c08f1b3c715b7b2f57228e78e34039d2b967f54a58e345bc91e3dd54c7bea86d73c9e2de968736bf2b97f50bea891aa3519ae7238d76dff57cabba7cc0d370775657f3b5c83";
// BigInteger sixthtest = new BigInteger(name,16);
// System.out.println("publicKey.getModulus():"+sixthtest.toString());
//
//
// String name1="10001";
// BigInteger sixthtest1 = new BigInteger(name1,16);
// System.out.println("pubkey exponent:"+sixthtest1.toString());
// String name2="4de9ca08bc97cab4f6b88db25203af709c5bae1a99de2269896b00f61a3ca886e5f56e66380ec1de7c97c6d19cb31a09c8b3714ae5e1d8e4658917b29a026db9e1dd79e7333a7419302cd526c9c2bec27ab7117d2fb31b51acfa4554815bf474414bd5faf0276f7cb98753658abedbed79efd940c14269d8b7a2c83422fa2181";
// BigInteger sixthtest2 = new BigInteger(name2,16);
// System.out.println("private exponent:"+sixthtest2.toString());
}
}
此处，要在应用的项目中添加一个jar包。
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