JAVA RSA加密公私钥
RSA加密算法：RSA加密算法是一种非对称加密算法。解密者拥有私钥，并且将由私钥计算生成的公钥发布给加密者。加密都使用公钥进行加密，并将密文发送到解密者，解密者用私钥解密将密文解码为明文。
RSA 密钥最少保存 3 个数，n，d，e
ne 组成公钥，nd 组成私钥
其中 e 一般固定 65537，因此知道私钥 nd 就能推出公钥
如果 e 不是 65537 就不一定能推出了
import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
public class RSAEncrypt {
private static Map<String, String> keyMap = new HashMap<String, String>(); //用于封装随机产生的公钥与私钥
private static Map<String, BigInteger> modMap = new HashMap<>();
public static void main(String[] args) throws Exception {
//生成公钥和私钥
genKeyPair();
//加密字符串
String message = "license";
System.out.println("随机生成的公钥为:" + keyMap.get("publicKeyString"));
System.out.println("随机生成的私钥为:" + keyMap.get("privateKeyString"));
String messageEn = encrypt(message,keyMap.get("privateKeyString"));//私钥加密
System.out.println(message + "\t加密后的字符串为:" + messageEn);
String messageDe = decrypt(messageEn,keyMap.get("publicKeyString"));//公钥解密
System.out.println("decrypt还原后的字符串为:" + messageDe);
String messageDeMod = decryptMod(messageEn,modMap.get("publicMod"), modMap.get("publicExp"));
System.out.println("decryptMod还原后的字符串为:" + messageDeMod);
String messageDeModStr = decryptModStr(messageEn,keyMap.get("publicModStr"), keyMap.get("publicExpStr"));
System.out.println("decryptModStr还原后的字符串为:" + messageDeModStr);
}
/**
* 随机生成密钥对
* @throws NoSuchAlgorithmException
*/
public static void genKeyPair() throws NoSuchAlgorithmException {
// KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
// 初始化密钥对生成器，密钥大小为96-1024位
keyPairGen.initialize(1024,new SecureRandom());
// 生成一个密钥对，保存在keyPair中
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 得到私钥
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 得到公钥
String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
// 得到私钥字符串
String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
// 将公钥和私钥保存到Map
keyMap.put("publicKeyString",publicKeyString);
keyMap.put("privateKeyString",privateKeyString);
String publicModStr = new String(Base64.encodeBase64((publicKey.getModulus().toByteArray())));
String publicExpStr = new String(Base64.encodeBase64((publicKey.getPublicExponent().toByteArray())));
String privateModStr = new String(Base64.encodeBase64((privateKey.getModulus().toByteArray())));
String privateExpStr = new String(Base64.encodeBase64((privateKey.getPrivateExponent().toByteArray())));
keyMap.put("publicModStr",publicModStr);
keyMap.put("publicExpStr",publicExpStr);
keyMap.put("privateModStr",privateModStr);
keyMap.put("privateExpStr",privateExpStr);
modMap.put("publicMod", publicKey.getModulus());
modMap.put("publicExp", publicKey.getPublicExponent());
modMap.put("privateMod", privateKey.getModulus());
modMap.put("privateExp", privateKey.getPrivateExponent());
System.out.println("publicModStr:"+publicModStr);
System.out.println("publicExpStr:"+publicExpStr);
System.out.println("publicMod:"+publicKey.getModulus());
System.out.println("publicExp:"+publicKey.getPublicExponent());
System.out.println("privateModStr:"+privateModStr);
System.out.println("privateExpStr:"+privateExpStr);
System.out.println("privateMod:"+privateKey.getModulus());
System.out.println("privateExp:"+privateKey.getPrivateExponent());
}
/**
* RSA私钥加密
*
* @param str
* 加密字符串
* @param privateKey
* 私钥
* @return 密文
* @throws Exception
* 加密过程中的异常信息
*/
public static String encrypt( String str, String privateKey ) throws Exception{
//base64编码的公钥
byte[] decoded = Base64.decodeBase64(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
//RSA加密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, priKey);
String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
return outStr;
}
/**
* RSA公钥解密
*
* @param str
* 加密字符串
* @param publicKey
* 公钥
* @return 铭文
* @throws Exception
* 解密过程中的异常信息
*/
public static String decrypt(String str, String publicKey) throws Exception{
//64位解码加密后的字符串
byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
//base64编码的公钥
byte[] decoded = Base64.decodeBase64(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
//RSA解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, pubKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
/**
* RSA公钥解密
*
* @param str
* 加密字符串
* @param publicMod
* 公钥模数
* @param publicExp
* 公钥指数
* @return 铭文
* @throws Exception
* 解密过程中的异常信息
*/
public static String decryptMod(String str, BigInteger publicMod, BigInteger publicExp) throws Exception{
//64位解码加密后的字符串
byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(publicMod, publicExp);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(pubKeySpec);
//RSA解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, pubKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
/**
* RSA公钥解密
*
* @param str
* 加密字符串
* @param publicModStr
* 公钥模数字符串
* @param publicExpStr
* 公钥指数字符串
* @return 铭文
* @throws Exception
* 解密过程中的异常信息
*/
public static String decryptModStr(String str, String publicModStr, String publicExpStr) throws Exception{
//64位解码加密后的字符串
byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
BigInteger publicMod = new BigInteger(Base64.decodeBase64(publicModStr));
BigInteger publicExp = new BigInteger(Base64.decodeBase64(publicExpStr));
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(publicMod, publicExp);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(pubKeySpec);
//RSA解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, pubKey);
String outStr = new String(cipher.doFinal(inputByte));
return outStr;
}
}
