【小工匠聊密码学】--对称加密--3DES

package lzf.cipher.jdk;

import java.nio.charset.Charset;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * @author Java小工匠
 */
public class JdkDes3Utils {

    // 获取 3DES Key
    public static byte[] get3DesKey() {
        try {
            // 1、创建密钥生成器
            KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");
            keyGenerator.init(168);
            // 2、产生密钥
            SecretKey secretKey = keyGenerator.generateKey();
            // 3、获取密钥
            byte[] key = secretKey.getEncoded();
            return key;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    // 3DES 加密
    public static byte[] encrypt3Des(byte[] data, byte[] key) {
        try {
            SecretKey secretKey = new SecretKeySpec(key, "DESede");
            String type = "DESede";
            // 加工作模式和填充方式
            type = "DESede/ECB/PKCS5Padding";
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            byte[] rsData = cipher.doFinal(data);
            return rsData;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    // 3DES 解密
    public static byte[] decrypt3Des(byte[] data, byte[] key) {
        try {
            SecretKey secretKey = new SecretKeySpec(key, "DESede");
            String type = "DESede";
            // 加工作模式和填充方式
            type = "DESede/ECB/PKCS5Padding";
            Cipher cipher = Cipher.getInstance(type);
            cipher.init(Cipher.DECRYPT_MODE, secretKey);
            byte[] rsData = cipher.doFinal(data);
            return rsData;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    // 数据准16进制编码
    public static String encodeHex(final byte[] data) {
        return encodeHex(data, true);
    }

    // 数据转16进制编码
    public static String encodeHex(final byte[] data, final boolean toLowerCase) {
        final char[] DIGITS_LOWER = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
        final char[] DIGITS_UPPER = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        final char[] toDigits = toLowerCase ? DIGITS_LOWER : DIGITS_UPPER;
        final int l = data.length;
        final char[] out = new char[l << 1];
        // two characters form the hex value.
        for (int i = 0, j = 0; i < l; i++) {
            out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
            out[j++] = toDigits[0x0F & data[i]];
        }
        return new String(out);
    }

    public static void main(String[] args) {
        byte[] data = "java小工匠".getBytes(Charset.forName("UTF-8"));
        byte[] key = get3DesKey();
        String hexKeyStr = encodeHex(key);
        System.out.println("加密密钥:" + hexKeyStr + ",length=" + hexKeyStr.length());
        byte[] encryptData = encrypt3Des(data, key);
        System.out.println("加密数据:" + encodeHex(encryptData));
        byte[] decryptData = decrypt3Des(encryptData, key);
        System.out.println("解密数据:" + new String(decryptData));
    }