Java实现的RSA加密解密算法示例

 import java.awt.AlphaComposite; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.Image; import java.awt.RenderingHints; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.security.Key; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.SecureRandom; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import javax.crypto.Cipher; public class RSAUtils{ public static String makekeyfile(String pubkeyfile, String prikeyfile) { String result = "生成公私钥文件失败"; try{ // KeyPairGenerator用于生成公私钥对，基于RSA算法生成对象 KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA"); // 初始化密钥对生成器，密钥大小为1024位 gen.initialize(1024); //    //生成强随机数 //    SecureRandom random = new SecureRandom(); //    gen.initialize(1024,random); // 生成一个密钥对，保存在pair中 KeyPair pair = gen.generateKeyPair(); // 得到私钥 RSAPrivateKey priKey = (RSAPrivateKey) pair.getPrivate(); // 得到公钥 RSAPublicKey pubKey = (RSAPublicKey) pair.getPublic(); // 生成私钥文件 ObjectOutputStream os = new ObjectOutputStream(new FileOutputStream(prikeyfile)); os.writeObject(priKey); os.flush(); os.close(); //生成公钥文件 os = new ObjectOutputStream(new FileOutputStream(pubkeyfile)); os.writeObject(pubKey); os.flush(); os.close(); result = "生成公钥文件【"+pubkeyfile+"】生成私钥文件【"+prikeyfile+"】"; }catch(Exception e){ e.printStackTrace(); } return result; } public static void main(String[] args) { try{ String pubfile = "F:/images/pub.key"; String prifile = "F:/images/pri.key"; String result = null; //result = makekeyfile(pubfile, prifile); result = markPuPra(pubfile, prifile); System.out.println(result); }catch(Exception e){ e.printStackTrace(); } } public static String markPuPra(String pubfile,String prifile){ String results = "加解密出错"; try{ ObjectInputStream os = new ObjectInputStream(new FileInputStream(pubfile)); RSAPublicKey pubkey = (RSAPublicKey) os.readObject(); os.close(); os = new ObjectInputStream(new FileInputStream(prifile)); RSAPrivateKey prikey = (RSAPrivateKey) os.readObject(); os.close(); String utf = "UTF-8"; String msg = "##中国%%的）人@+_"; // 使用公钥加密私钥解密 System.out.println("原文: " + msg); byte[] puk = handleData(pubkey, msg.getBytes(utf), 1); System.out.println("加密后文件数据: " + new String(puk, utf)); byte[] dpuk = handleData(prikey, puk, 0); System.out.println("解密后文件数据: " + new String(dpuk, utf)); msg = "jd#我0们的￥人+=#新"; // 使用私钥加密公钥解密 System.out.println("原文: " + msg); byte[] prk = handleData(prikey, msg.getBytes(utf), 1); System.out.println("加密后文件数据: " + new String(prk, utf)); byte[] dprk = handleData(pubkey, prk, 0); System.out.println("解密后文件数据: " + new String(dprk, utf)); results = "加解密完成"; }catch(Exception e){ e.printStackTrace(); } return results; } /** * * @param k * @param data * @param encrypt 1 加密 0解密 * @return * @throws Exception */ public static byte[] handleData(Key key, byte[] data, int type) throws Exception { if (key != null) { Cipher ci = Cipher.getInstance("RSA"); if (type == 1) { ci.init(Cipher.ENCRYPT_MODE, key); byte[] res = ci.doFinal(data); return res; } if (type == 0) { ci.init(Cipher.DECRYPT_MODE, key); byte[] res = ci.doFinal(data); return res; } } return null; } }