Android RSA 公钥加密、解密

package com.linekong.sdk.utils;

import java.security.KeyFactory;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import android.util.Base64;

/**
* @author changcsw 2015-11-11
*
*/
public class RSAUtils {
private static RSAPublicKey publicKey = null;
/**************************** RSA 公钥加密解密**************************************/
/**
* 从字符串中加载公钥,从服务端获取
*
* @param publicKeyStr
* 公钥数据字符串
* @throws Exception
* 加载公钥时产生的异常
*/
public static void loadPublicKey(String pubKey) {
try {
byte[] buffer = Base64.decode(pubKey, Base64.DEFAULT);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
publicKey = (RSAPublicKey) keyFactory.generatePublic(keySpec);
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* 公钥加密过程
*
* @param publicKey
* 公钥
* @param plainData
* 明文数据
* @return
* @throws Exception
* 加密过程中的异常信息
*/
public static String encryptWithRSA(String plainData) throws Exception {
if (publicKey == null) {
throw new NullPointerException("encrypt PublicKey is null !");
}

Cipher cipher = null;
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");// 此处如果写成"RSA"加密出来的信息JAVA服务器无法解析

cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] output = cipher.doFinal(plainData.getBytes("utf-8"));
// 必须先encode成 byte[]，再转成encodeToString，否则服务器解密会失败
byte[] encode = Base64.encode(output, Base64.DEFAULT);
return Base64.encodeToString(encode, Base64.DEFAULT);
}

/**
* 公钥解密过程
*
* @param publicKey
* 公钥
* @param encryedData
* 明文数据
* @return
* @throws Exception
* 加密过程中的异常信息
*/
public static String decryptWithRSA(String encryedData) throws Exception {
if (publicKey == null) {
throw new NullPointerException("decrypt PublicKey is null !");
}

Cipher cipher = null;
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");// 此处如果写成"RSA"解析的数据前多出来些乱码
cipher.init(Cipher.DECRYPT_MODE, publicKey);
byte[] output = cipher.doFinal(Base64.decode(encryedData, Base64.DEFAULT));
return new String(output);
}
/**************************** RSA 公钥加密解密**************************************/
}

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