java的RSA加密

 

package com.jetsum.util;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.security.InvalidKeyException;import java.security.Key;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.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;import javax.crypto.BadPaddingException;import javax.crypto.Cipher;import javax.crypto.IllegalBlockSizeException;import javax.crypto.NoSuchPaddingException;import sun.misc.BASE64Decoder;import sun.misc.BASE64Encoder;/** * RSA算法，实现数据的加密解密。 * @author ShaoJiang * */public class RSAUtil {private static Cipher cipher;static{try {cipher = Cipher.getInstance("RSA");} catch (NoSuchAlgorithmException e) {e.printStackTrace();} catch (NoSuchPaddingException e) {e.printStackTrace();}}/** * 生成密钥对 * @param filePath 生成密钥的路径 * @return */public static Map<String,String> generateKeyPair(String filePath){try {KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");// 密钥位数keyPairGen.initialize(1024);// 密钥对KeyPair keyPair = keyPairGen.generateKeyPair();// 公钥PublicKey publicKey = (RSAPublicKey) keyPair.getPublic();// 私钥PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();//得到公钥字符串String publicKeyString = getKeyString(publicKey);//得到私钥字符串String privateKeyString = getKeyString(privateKey);//将密钥对写入到文件FileWriter pubfw = new FileWriter(filePath+"/publicKey.keystore");FileWriter prifw = new FileWriter(filePath+"/privateKey.keystore");BufferedWriter pubbw = new BufferedWriter(pubfw);BufferedWriter pribw = new BufferedWriter(prifw);pubbw.write(publicKeyString);pribw.write(privateKeyString);pubbw.flush();pubbw.close();pubfw.close();pribw.flush();pribw.close();prifw.close();//将生成的密钥对返回Map<String,String> map = new HashMap<String,String>();map.put("publicKey",publicKeyString);map.put("privateKey",privateKeyString);return map;} catch (Exception e) {e.printStackTrace();}return null;}/** * 得到公钥 *  * @param key *            密钥字符串（经过base64编码） * @throws Exception */public static PublicKey getPublicKey(String key) throws Exception {byte[] keyBytes;keyBytes = (new BASE64Decoder()).decodeBuffer(key);X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);KeyFactory keyFactory = KeyFactory.getInstance("RSA");PublicKey publicKey = keyFactory.generatePublic(keySpec);return publicKey;}/** * 得到私钥 *  * @param key *            密钥字符串（经过base64编码） * @throws Exception */public static PrivateKey getPrivateKey(String key) throws Exception {byte[] keyBytes;keyBytes = (new BASE64Decoder()).decodeBuffer(key);PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);KeyFactory keyFactory = KeyFactory.getInstance("RSA");PrivateKey privateKey = keyFactory.generatePrivate(keySpec);return privateKey;}/** * 得到密钥字符串（经过base64编码） *  * @return */public static String getKeyString(Key key) throws Exception {byte[] keyBytes = key.getEncoded();String s = (new BASE64Encoder()).encode(keyBytes);return s;}   /** * 使用公钥对明文进行加密，返回BASE64编码的字符串 * @param publicKey * @param plainText * @return */public static String encrypt(PublicKey publicKey,String plainText){try {cipher.init(Cipher.ENCRYPT_MODE, publicKey);byte[] enBytes = cipher.doFinal(plainText.getBytes());return (new BASE64Encoder()).encode(enBytes);} catch (InvalidKeyException e) {e.printStackTrace();} catch (IllegalBlockSizeException e) {e.printStackTrace();} catch (BadPaddingException e) {e.printStackTrace();}return null;}/** * 使用keystore对明文进行加密 * @param publicKeystore 公钥文件路径 * @param plainText      明文 * @return */public static String encrypt(String publicKeystore,String plainText){try {FileReader fr = new FileReader(publicKeystore);BufferedReader br = new BufferedReader(fr);String publicKeyString="";String str;while((str=br.readLine())!=null){publicKeyString+=str;}br.close();fr.close();cipher.init(Cipher.ENCRYPT_MODE,getPublicKey(publicKeyString));byte[] enBytes = cipher.doFinal(plainText.getBytes());return (new BASE64Encoder()).encode(enBytes);} catch (InvalidKeyException e) {e.printStackTrace();} catch (IllegalBlockSizeException e) {e.printStackTrace();} catch (BadPaddingException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}return null;}/** * 使用私钥对明文密文进行解密 * @param privateKey * @param enStr * @return */public static String decrypt(PrivateKey privateKey,String enStr){try {cipher.init(Cipher.DECRYPT_MODE, privateKey);byte[] deBytes = cipher.doFinal((new BASE64Decoder()).decodeBuffer(enStr));return new String(deBytes);} catch (InvalidKeyException e) {e.printStackTrace();} catch (IllegalBlockSizeException e) {e.printStackTrace();} catch (BadPaddingException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return null;}/** * 使用keystore对密文进行解密 * @param privateKeystore  私钥路径 * @param enStr                                     密文 * @return */public static String decrypt(String privateKeystore,String enStr){try {FileReader fr = new FileReader(privateKeystore);BufferedReader br = new BufferedReader(fr);String privateKeyString="";String str;while((str=br.readLine())!=null){privateKeyString+=str;}br.close();fr.close();cipher.init(Cipher.DECRYPT_MODE, getPrivateKey(privateKeyString));byte[] deBytes = cipher.doFinal((new BASE64Decoder()).decodeBuffer(enStr));return new String(deBytes);} catch (InvalidKeyException e) {e.printStackTrace();} catch (IllegalBlockSizeException e) {e.printStackTrace();} catch (BadPaddingException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}return null;}}