RSA加密算法Java语言版

import java.math.BigInteger; 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.InvalidKeySpecException; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.RSAPrivateKeySpec; import java.security.spec.RSAPublicKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.HashMap; import javax.crypto.Cipher; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; public class RSA_master { private static HashMap<String,String> map = new HashMap<String,String>(); public static void main(String[] args) throws InvalidKeySpecException { try { //创建RSA加密 KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA"); //密钥位数 keyPairGen.initialize(1024); // 动态生成密钥对，这是当前最耗时的操作，一般要2s以上。 KeyPair key = keyPairGen.generateKeyPair(); //公钥 PublicKey publicKey = key.getPublic(); //密钥 PrivateKey privateKey = key.getPrivate(); printPrivateKey(privateKey); printPublicKey(publicKey); // 公钥比特编码 // byte[] privateData = privateKey.getEncoded(); //对应着getPrivateKey()方法 //密钥比特编码 // byte[] publicData = publicKey.getEncoded(); //对应着getPublicKey()方法 String message ="吕双，我的女朋友"; String inputStr = encrypt(message, new String(new BASE64Encoder().encodeBuffer(publicKey.getEncoded()))); System.out.println(inputStr); System.out.println(decrypt(inputStr, new String(new BASE64Encoder().encodeBuffer(privateKey.getEncoded())))); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } // 通过公钥byte[]将公钥还原，适用于RSA算法 public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,InvalidKeySpecException { X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PublicKey publicKey = keyFactory.generatePublic(keySpec); return publicKey; } //通过私钥byte[]将密钥还原，适用于RSA算法 public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,InvalidKeySpecException{ PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PrivateKey privateKey = keyFactory.generatePrivate(keySpec); return privateKey; } //打印公钥信息 public static void printPublicKey(PublicKey publicKey) { RSAPublicKey key = (RSAPublicKey)publicKey; map.put("N", key.getModulus().toString()); map.put("E", key.getPublicExponent().toString()); } //获取私钥信息 public static void printPrivateKey(PrivateKey privateKey) { RSAPrivateKey key = (RSAPrivateKey)privateKey; map.put("D", key.getPrivateExponent().toString()); } // 使用N、E值还原公钥 public static PublicKey getPublicKeyByN_E(String N,String E) throws NoSuchAlgorithmException, InvalidKeySpecException { BigInteger bigN = new BigInteger(N); BigInteger bigE = new BigInteger(E); RSAPublicKeySpec spec = new RSAPublicKeySpec(bigN, bigE); KeyFactory factory = KeyFactory.getInstance("RSA"); return factory.generatePublic(spec); } // 使用N、D值还原公钥 public static PrivateKey getPrivateKeyByN_D(String N,String D) throws NoSuchAlgorithmException, InvalidKeySpecException { BigInteger bigN = new BigInteger(N); BigInteger bigD = new BigInteger(D); RSAPrivateKeySpec spec = new RSAPrivateKeySpec(bigN, bigD); KeyFactory factory = KeyFactory.getInstance("RSA"); return factory.generatePrivate(spec); } //加密 /* * 公钥加密 * @Param str : 加密字符串 * @Param publicKey : 公钥 * return : 密文 */ public static String encrypt(String str , String publicKey) throws Exception { //base64编码的公钥 byte[] decoded = new BASE64Decoder().decodeBuffer(publicKey); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(decoded); RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(keySpec); //RSA加密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, pubKey); String outStr = new BASE64Encoder().encode(cipher.doFinal(str.getBytes("UTF-8"))); return outStr; } /* * RSA私钥解密 * @param str :加密后的字符串 * @param privateKey : 解密后的字符串 */ public static String decrypt(String str,String privateKey) throws Exception{ //64位解码加密后的字符串 byte[] inputStr = new BASE64Decoder().decodeBuffer(new String(str.getBytes("utf-8"),"utf-8")); //base64解码的私钥 byte[] decode = new BASE64Decoder().decodeBuffer(privateKey); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decode); RSAPrivateKey priKey = (RSAPrivateKey)KeyFactory.getInstance("RSA").generatePrivate(keySpec); Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, priKey); String outStr = new String(cipher.doFinal(inputStr)); return outStr; } }