RSAEncrypt.java

public class RSAEncrypt {
  
	private static final String DEFAULT_PUBLIC_KEY= 
		"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQChDzcjw/rWgFwnxunbKp7/4e8w" + "\r" +
		"/UmXx2jk6qEEn69t6N2R1i/LmcyDT1xr/T2AHGOiXNQ5V8W4iCaaeNawi7aJaRht" + "\r" +
		"Vx1uOH/2U378fscEESEG8XDqll0GCfB1/TjKI2aitVSzXOtRs8kYgGU78f7VmDNg" + "\r" +
		"XIlk3gdhnzh+uoEQywIDAQAB" + "\r";
	
	private static final String DEFAULT_PRIVATE_KEY=
		"MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBAKEPNyPD+taAXCfG" + "\r" +
		"6dsqnv/h7zD9SZfHaOTqoQSfr23o3ZHWL8uZzINPXGv9PYAcY6Jc1DlXxbiIJpp4" + "\r" +
		"1rCLtolpGG1XHW44f/ZTfvx+xwQRIQbxcOqWXQYJ8HX9OMojZqK1VLNc61GzyRiA" + "\r" +
		"ZTvx/tWYM2BciWTeB2GfOH66gRDLAgMBAAECgYBp4qTvoJKynuT3SbDJY/XwaEtm" + "\r" +
		"u768SF9P0GlXrtwYuDWjAVue0VhBI9WxMWZTaVafkcP8hxX4QZqPh84td0zjcq3j" + "\r" +
		"DLOegAFJkIorGzq5FyK7ydBoU1TLjFV459c8dTZMTu+LgsOTD11/V/Jr4NJxIudo" + "\r" +
		"MBQ3c4cHmOoYv4uzkQJBANR+7Fc3e6oZgqTOesqPSPqljbsdF9E4x4eDFuOecCkJ" + "\r" +
		"DvVLOOoAzvtHfAiUp+H3fk4hXRpALiNBEHiIdhIuX2UCQQDCCHiPHFd4gC58yyCM" + "\r" +
		"6Leqkmoa+6YpfRb3oxykLBXcWx7DtbX+ayKy5OQmnkEG+MW8XB8wAdiUl0/tb6cQ" + "\r" +
		"FaRvAkBhvP94Hk0DMDinFVHlWYJ3xy4pongSA8vCyMj+aSGtvjzjFnZXK4gIjBjA" + "\r" +
		"2Z9ekDfIOBBawqp2DLdGuX2VXz8BAkByMuIh+KBSv76cnEDwLhfLQJlKgEnvqTvX" + "\r" +
		"TB0TUw8avlaBAXW34/5sI+NUB1hmbgyTK/T/IFcEPXpBWLGO+e3pAkAGWLpnH0Zh" + "\r" +
		"Fae7oAqkMAd3xCNY6ec180tAe57hZ6kS+SYLKwb4gGzYaCxc22vMtYksXHtUeamo" + "\r" +
		"1NMLzI2ZfUoX" + "\r";

	/**
	 * 私钥
	 */
	private RSAPrivateKey privateKey;

	/**
	 * 公钥
	 */
	private RSAPublicKey publicKey;
	
	/**
	 * 字节数据转字符串专用集合
	 */
	private static final char[] HEX_CHAR= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
	

	/**
	 * 获取私钥
	 * @return 当前的私钥对象
	 */
	public RSAPrivateKey getPrivateKey() {
		return privateKey;
	}

	/**
	 * 获取公钥
	 * @return 当前的公钥对象
	 */
	public RSAPublicKey getPublicKey() {
		return publicKey;
	}

	/**
	 * 随机生成密钥对
	 */
	public void genKeyPair(){
		KeyPairGenerator keyPairGen= null;
		try {
			keyPairGen= KeyPairGenerator.getInstance("RSA");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		keyPairGen.initialize(1024, new SecureRandom());
		KeyPair keyPair= keyPairGen.generateKeyPair();
		this.privateKey= (RSAPrivateKey) keyPair.getPrivate();
		this.publicKey= (RSAPublicKey) keyPair.getPublic();
	}

	/**
	 * 从文件中输入流中加载公钥
	 * @param in 公钥输入流
	 * @throws Exception 加载公钥时产生的异常
	 */
	public void loadPublicKey(InputStream in) throws Exception{
		try {
			BufferedReader br= new BufferedReader(new InputStreamReader(in));
			String readLine= null;
			StringBuilder sb= new StringBuilder();
			while((readLine= br.readLine())!=null){
				if(readLine.charAt(0)=='-'){
					continue;
				}else{
					sb.append(readLine);
					sb.append('\r');
				}
			}
			loadPublicKey(sb.toString());
		} catch (IOException e) {
			throw new Exception("公钥数据流读取错误");
		} catch (NullPointerException e) {
			throw new Exception("公钥输入流为空");
		}
	}


	/**
	 * 从字符串中加载公钥
	 * @param publicKeyStr 公钥数据字符串
	 * @throws Exception 加载公钥时产生的异常
	 */
	public void loadPublicKey(String publicKeyStr) throws Exception{
		try {
			BASE64Decoder base64Decoder= new BASE64Decoder();
			byte[] buffer= base64Decoder.decodeBuffer(publicKeyStr);
			KeyFactory keyFactory= KeyFactory.getInstance("RSA");
			X509EncodedKeySpec keySpec= new X509EncodedKeySpec(buffer);
			this.publicKey= (RSAPublicKey) keyFactory.generatePublic(keySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此算法");
		} catch (InvalidKeySpecException e) {
			throw new Exception("公钥非法");
		} catch (IOException e) {
			throw new Exception("公钥数据内容读取错误");
		} catch (NullPointerException e) {
			throw new Exception("公钥数据为空");
		}
	}

	/**
	 * 从文件中加载私钥
	 * @param keyFileName 私钥文件名
	 * @return 是否成功
	 * @throws Exception 
	 */
	public void loadPrivateKey(InputStream in) throws Exception{
		try {
			BufferedReader br= new BufferedReader(new InputStreamReader(in));
			String readLine= null;
			StringBuilder sb= new StringBuilder();
			while((readLine= br.readLine())!=null){
				if(readLine.charAt(0)=='-'){
					continue;
				}else{
					sb.append(readLine);
					sb.append('\r');
				}
			}
			loadPrivateKey(sb.toString());
		} catch (IOException e) {
			throw new Exception("私钥数据读取错误");
		} catch (NullPointerException e) {
			throw new Exception("私钥输入流为空");
		}
	}

	public void loadPrivateKey(String privateKeyStr) throws Exception{
		try {
			BASE64Decoder base64Decoder= new BASE64Decoder();
			byte[] buffer= base64Decoder.decodeBuffer(privateKeyStr);
			PKCS8EncodedKeySpec keySpec= new PKCS8EncodedKeySpec(buffer);
			KeyFactory keyFactory= KeyFactory.getInstance("RSA");
			this.privateKey= (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此算法");
		} catch (InvalidKeySpecException e) {
			throw new Exception("私钥非法");
		} catch (IOException e) {
			throw new Exception("私钥数据内容读取错误");
		} catch (NullPointerException e) {
			throw new Exception("私钥数据为空");
		}
	}

	/**
	 * 加密过程
	 * @param publicKey 公钥
	 * @param plainTextData 明文数据
	 * @return
	 * @throws Exception 加密过程中的异常信息
	 */
	public byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception{
		if(publicKey== null){
			throw new Exception("加密公钥为空, 请设置");
		}
		Cipher cipher= null;
		try {
			cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.ENCRYPT_MODE, publicKey);
			byte[] output= cipher.doFinal(plainTextData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此加密算法");
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
			return null;
		}catch (InvalidKeyException e) {
			throw new Exception("加密公钥非法,请检查");
		} catch (IllegalBlockSizeException e) {
			throw new Exception("明文长度非法");
		} catch (BadPaddingException e) {
			throw new Exception("明文数据已损坏");
		}
	}

	/**
	 * 解密过程
	 * @param privateKey 私钥
	 * @param cipherData 密文数据
	 * @return 明文
	 * @throws Exception 解密过程中的异常信息
	 */
	public byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception{
		if (privateKey== null){
			throw new Exception("解密私钥为空, 请设置");
		}
		Cipher cipher= null;
		try {
			cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.DECRYPT_MODE, privateKey);
			byte[] output= cipher.doFinal(cipherData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此解密算法");
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
			return null;
		}catch (InvalidKeyException e) {
			throw new Exception("解密私钥非法,请检查");
		} catch (IllegalBlockSizeException e) {
			throw new Exception("密文长度非法");
		} catch (BadPaddingException e) {
			throw new Exception("密文数据已损坏");
		}		
	}

	
	/**
	 * 字节数据转十六进制字符串
	 * @param data 输入数据
	 * @return 十六进制内容
	 */
	public static String byteArrayToString(byte[] data){
		StringBuilder stringBuilder= new StringBuilder();
		for (int i=0; i<data.length; i++){
			//取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移
			stringBuilder.append(HEX_CHAR[(data[i] & 0xf0)>>> 4]);
			//取出字节的低四位 作为索引得到相应的十六进制标识符
			stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);
			if (i<data.length-1){
				stringBuilder.append(' ');
			}
		}
		return stringBuilder.toString();
	}


	public static void main(String[] args){
		RSAEncrypt rsaEncrypt= new RSAEncrypt();
		//rsaEncrypt.genKeyPair();

		//加载公钥
		try {
			rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY);
			System.out.println("加载公钥成功");
		} catch (Exception e) {
			System.err.println(e.getMessage());
			System.err.println("加载公钥失败");
		}

		//加载私钥
		try {
			rsaEncrypt.loadPrivateKey(RSAEncrypt.DEFAULT_PRIVATE_KEY);
			System.out.println("加载私钥成功");
		} catch (Exception e) {
			System.err.println(e.getMessage());
			System.err.println("加载私钥失败");
		}

		//测试字符串
		String encryptStr= "Test String chaijunkun";

		try {
			//加密
			byte[] cipher = rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), encryptStr.getBytes());
			//解密
			byte[] plainText = rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), cipher);
			System.out.println("密文长度:"+ cipher.length);
			System.out.println(RSAEncrypt.byteArrayToString(cipher));
			System.out.println("明文长度:"+ plainText.length);
			System.out.println(RSAEncrypt.byteArrayToString(plainText));
			System.out.println(new String(plainText));
		} catch (Exception e) {
			System.err.println(e.getMessage());
		}
	}
}