JAVA RSA 加密解密工具类支持分片

约定不等于承诺〃 2022-04-11 12:48 277阅读 0赞

package com.ming.util;
    
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.ObjectInputStream;
    import java.io.ObjectOutputStream;
    import java.security.Key;
    import java.security.KeyFactory;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.PrivateKey;
    import java.security.PublicKey;
    import java.security.SecureRandom;
    import java.security.Signature;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    
    import javax.crypto.Cipher;
    
    import sun.misc.BASE64Decoder;
    import sun.misc.BASE64Encoder;
    
    /**
     * RSA加密，支持分片加密
     * <pre>
     * BCD码（Binary-Coded Decimal‎）亦称二进码十进数或二-十进制代码。
     * 用4位二进制数来表示1位十进制数中的0~9这10个数码。
     * 是一种二进制的数字编码形式，用二进制编码的十进制代码。
     * 注：日常所说的BCD码大都是指8421BCD码形式
     * @author Ming
     * 
     */
    public class RSAUtil {
    	/** 指定加密算法为RSA */
    	private static String ALGORITHM = "RSA";
    	/** 指定key的大小 */
    	private static int KEYSIZE = 1024;
    	/** 指定公钥存放文件 */
    	private static String PUBLIC_KEY_FILE = "PublicKey";
    	/** 指定私钥存放文件 */
    	private static String PRIVATE_KEY_FILE = "PrivateKey";
    
    	public static final String KEY_ALGORITHM = "RSA";
    	public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
    
    	/**
    	 * 生成密钥对
    	 */
    	public static void generateKeyPair() throws Exception {
    		if (getpublickey() == null || getprivatekey() == null) {
    			/** RSA算法要求有一个可信任的随机数源 */
    			SecureRandom sr = new SecureRandom();
    			/** 为RSA算法创建一个KeyPairGenerator对象 */
    			KeyPairGenerator kpg = KeyPairGenerator.getInstance(ALGORITHM);
    			/** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */
    			kpg.initialize(KEYSIZE, sr);
    			/** 生成密匙对 */
    			KeyPair kp = kpg.generateKeyPair();
    			/** 得到公钥 */
    			Key publicKey = kp.getPublic();
    			/** 得到私钥 */
    			Key privateKey = kp.getPrivate();
    			/** 用对象流将生成的密钥写入文件 */
    			ObjectOutputStream oos1 = new ObjectOutputStream(new FileOutputStream(PUBLIC_KEY_FILE));
    			ObjectOutputStream oos2 = new ObjectOutputStream(new FileOutputStream(PRIVATE_KEY_FILE));
    			oos1.writeObject(publicKey);
    			oos2.writeObject(privateKey);
    			/** 清空缓存，关闭文件输出流 */
    			oos1.close();
    			oos2.close();
    		}
    
    	}
    
    	/**
    	 * 产生签名
    	 * 
    	 * @param data
    	 * @param privateKey
    	 * @return
    	 * @throws Exception
    	 */
    	public static String sign(byte[] data, String privateKey) throws Exception {
    		// 解密由base64编码的私钥
    		byte[] keyBytes = decryptBASE64(privateKey);
    
    		// 构造PKCS8EncodedKeySpec对象
    		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    
    		// KEY_ALGORITHM 指定的加密算法
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    
    		// 取私钥对象
    		PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
    
    		// 用私钥对信息生成数字签名
    		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
    		signature.initSign(priKey);
    		signature.update(data);
    
    		return encryptBASE64(signature.sign());
    	}
    
    	/**
    	 * 验证签名
    	 * 
    	 * @param data
    	 * @param publicKey
    	 * @param sign
    	 * @return
    	 * @throws Exception
    	 */
    	public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
    
    		// 解密由base64编码的公钥
    		byte[] keyBytes = decryptBASE64(publicKey);
    
    		// 构造X509EncodedKeySpec对象
    		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
    
    		// KEY_ALGORITHM 指定的加密算法
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    
    		// 取公钥对象
    		PublicKey pubKey = keyFactory.generatePublic(keySpec);
    
    		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
    		signature.initVerify(pubKey);
    		signature.update(data);
    
    		// 验证签名是否有效
    		return signature.verify(decryptBASE64(sign));
    	}
    
    	/**
    	 * BASE64解密
    	 * 
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static byte[] decryptBASE64(String key) throws Exception {
    		return (new BASE64Decoder()).decodeBuffer(key);
    	}
    
    	/**
    	 * BASE64加密
    	 * 
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static String encryptBASE64(byte[] key) throws Exception {
    		return (new BASE64Encoder()).encodeBuffer(key);
    	}
    
    	/**
    	 * 加密方法 source： 源数据
    	 */
    	public static String encrypt(String source) throws Exception {
    		generateKeyPair();
    		/** 将文件中的公钥对象读出 */
    		ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
    		Key key = (Key) ois.readObject();
    		ois.close();
    		/** 得到Cipher对象来实现对源数据的RSA加密 */
    		Cipher cipher = Cipher.getInstance(ALGORITHM);
    		cipher.init(Cipher.ENCRYPT_MODE, key);
    		int MaxBlockSize = KEYSIZE / 8;
    		int len = (MaxBlockSize - 11) / 8;
    		String[] datas = splitString(source, len);
    		StringBuffer mi = new StringBuffer();
    		for (String s : datas) {
    			mi.append(bcd2Str(cipher.doFinal(s.getBytes())));
    		}
    		return mi.toString();
    
    	}
    
    	/**
    	 * 字符串分片
    	 * 
    	 * @param string
    	 *            源字符串
    	 * @param len
    	 *            单片的长度（keysize/8）
    	 * @return
    	 */
    	public static String[] splitString(String string, int len) {
    		int x = string.length() / len;
    		int y = string.length() % len;
    		int z = 0;
    		if (y != 0) {
    			z = 1;
    		}
    		String[] strings = new String[x + z];
    		String str = "";
    		for (int i = 0; i < x + z; i++) {
    			if (i == x + z - 1 && y != 0) {
    				str = string.substring(i * len, i * len + y);
    			} else {
    				str = string.substring(i * len, i * len + len);
    			}
    			strings[i] = str;
    		}
    		return strings;
    	}
    
    	/**
    	 * bcd 转 Str
    	 * 
    	 * @param bytes
    	 * @return
    	 */
    	public static String bcd2Str(byte[] bytes) {
    		char temp[] = new char[bytes.length * 2], val;
    		for (int i = 0; i < bytes.length; i++) {
    			val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);
    			temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
    
    			val = (char) (bytes[i] & 0x0f);
    			temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
    		}
    		return new String(temp);
    	}
    
    	/**
    	 * 解密
    	 * 
    	 * @param cryptograph
    	 *            :密文
    	 * @return 解密后的明文
    	 * @throws Exception
    	 */
    	public static String decrypt(String cryptograph) throws Exception {
    		generateKeyPair();
    		/** 将文件中的私钥对象读出 */
    		@SuppressWarnings("resource")
    		ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
    		Key key = (Key) ois.readObject();
    		/** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
    		Cipher cipher = Cipher.getInstance(ALGORITHM);
    		cipher.init(Cipher.DECRYPT_MODE, key);
    		int key_len = KEYSIZE / 8;
    		byte[] bytes = cryptograph.getBytes();
    		byte[] bcd = ASCII2BCD(bytes, bytes.length);
    		StringBuffer sBuffer = new StringBuffer();
    		byte[][] arrays = splitArray(bcd, key_len);
    		for (byte[] arr : arrays) {
    			sBuffer.append(new String(cipher.doFinal(arr)));
    		}
    		return sBuffer.toString();
    	}
    
    	/**
    	 * ASCII 转 BCD
    	 * 
    	 * @param ascii
    	 * @param asc_len
    	 * @return
    	 */
    	public static byte[] ASCII2BCD(byte[] ascii, int asc_len) {
    		byte[] bcd = new byte[asc_len / 2];
    		int j = 0;
    		for (int i = 0; i < (asc_len + 1) / 2; i++) {
    			bcd[i] = asc2bcd(ascii[j++]);
    			bcd[i] = (byte) (((j >= asc_len) ? 0x00 : asc2bcd(ascii[j++])) + (bcd[i] << 4));
    		}
    		return bcd;
    	}
    
    	/**
    	 * asc转bcd
    	 * 
    	 * @param asc
    	 * @return
    	 */
    	public static byte asc2bcd(byte asc) {
    		byte bcd;
    
    		if ((asc >= '0') && (asc <= '9'))
    			bcd = (byte) (asc - '0');
    		else if ((asc >= 'A') && (asc <= 'F'))
    			bcd = (byte) (asc - 'A' + 10);
    		else if ((asc >= 'a') && (asc <= 'f'))
    			bcd = (byte) (asc - 'a' + 10);
    		else
    			bcd = (byte) (asc - 48);
    		return bcd;
    	}
    
    	/**
    	 * 字节数组分片
    	 * 
    	 * @param data
    	 * @param len
    	 * @return
    	 */
    	public static byte[][] splitArray(byte[] data, int len) {
    		int x = data.length / len;
    		int y = data.length % len;
    		int z = 0;
    		if (y != 0) {
    			z = 1;
    		}
    		byte[][] arrays = new byte[x + z][];
    		byte[] arr;
    		for (int i = 0; i < x + z; i++) {
    			arr = new byte[len];
    			if (i == x + z - 1 && y != 0) {
    				System.arraycopy(data, i * len, arr, 0, y);
    			} else {
    				System.arraycopy(data, i * len, arr, 0, len);
    			}
    			arrays[i] = arr;
    		}
    		return arrays;
    	}
    
    	/** 将文件中的公钥对象读出 */
    	public static String getpublickey() {
    
    		try {
    			@SuppressWarnings("resource")
    			ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
    			Key key = (Key) ois.readObject();
    			String publickey = encryptBASE64(key.getEncoded());
    			return publickey;
    		} catch (Exception e) {
    			LogUtil.exception(e);
    		}
    		return null;
    	}
    
    	/** 将文件中的私钥对象读出 */
    	public static String getprivatekey() {
    		try {
    			@SuppressWarnings("resource")
    			ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
    			Key key = (Key) ois.readObject();
    			String privatekey = encryptBASE64(key.getEncoded());
    			return privatekey;
    		} catch (Exception e) {
    			LogUtil.exception(e);
    		}
    		return null;
    	}
    
    	public static void main(String[] args) {
    		try {
    			String s = encrypt("allming.com");
    			System.out.println("加密："+s);
    			System.out.println("解密："+decrypt(s));
    
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }