Java之AES/ECB/PKCS7Padding加密方式

AES/ECB/PKCS7Padding7加密

简介：
在Java开发中，用到的AES的ECB加密模式、PKCS7Padding填充方式，Java目前仅支持PKCS5Padding填充模式，今天我将带领大家了解下，PKCS7Padding填充模式，希望可以帮到Java的开发人员，
目前Java要实现PKCS7Padding填充模式的加密，需要借助第三方Jar包才可以实现，就是在初始化的时候 Security.addProvider 增加第三方的提供者，解密的时候还是按照原来的方式。

Maven依赖：

		
			org.bouncycastle
			bcprov-jdk15on
			1.56
		

示例代码：

package com.tencent.sxwx.payment.util;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * AES 加密 ECB 模式 PKCS7Padding 填充模式
 * 
 * @author
 *
 */
public class AESECBPKCS7Padding {

	static String ENCRYPT_CHARSET = "UTF-8";
	static String mode = "AES/ECB/PKCS7Padding";

	public static void main(String[] args) throws Exception {
		String content = "hello World";
		String password = "151";
		System.out.println("原内容：\n"+content);
		String tempContent = encrypt(content,password,mode);
		System.err.println("加密后：\n"+tempContent);
		tempContent = decrypt(tempContent, password,mode );
		System.out.println("解密后：\n"+tempContent);
	}

	public static String encrypt(String content, String password, String mode) {
		try {
			SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			secureRandom.setSeed(password.getBytes());
			kgen.init(128, secureRandom);
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
			Cipher cipher = Cipher.getInstance(mode);// 创建密码器
			byte[] byteContent = content.getBytes(ENCRYPT_CHARSET);
			cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
			byte[] result = cipher.doFinal(byteContent);
			if (result != null && result.length > 0) {
				/*
				 * 注意： return new String(result,ENCRYPT_CHARSET);
				 * 会出现javax.crypto.IllegalBlockSizeException: Input length must be multiple of
				 * 16 when decrypting with padded cipher 加密后的byte数组是不能强制转换成字符串的，
				 * 字符串和byte数组在这种情况下不是互逆的； 需要将二进制数据转换成十六进制表示
				 */
				return parseByte2HexStr(result);
			}
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 解密
	 * 
	 * @param content  待解密内容
	 * @param password 解密密钥
	 * @return
	 */
	public static String decrypt(String content, String password, String mode) throws Exception {
		try {
			if (content == null) {
				return null;
			}

			byte[] newContent = parseHexStr2Byte(content);// 将16进制转换为二进制
			SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			secureRandom.setSeed(password.getBytes());
			kgen.init(128, secureRandom);
			// kgen.init(128, new SecureRandom(password.getBytes()));
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance(mode);// 创建密码器
			cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
			byte[] result = cipher.doFinal(newContent);
			if (result != null && result.length > 0) {
				return new String(result, "UTF-8");
			}
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 将二进制转换成16进制
	 * 
	 * @param buf
	 * @return
	 */
	public static String parseByte2HexStr(byte buf[]) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < buf.length; i++) {
			String hex = Integer.toHexString(buf[i] & 0xFF);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			sb.append(hex.toUpperCase());
		}
		return sb.toString();
	}

	/**
	 * 将16进制转换为二进制
	 * 
	 * @param hexStr
	 * @return
	 */
	public static byte[] parseHexStr2Byte(String hexStr) {
		if (hexStr.length() < 1)
			return null;
		byte[] result = new byte[hexStr.length() / 2];
		for (int i = 0; i < hexStr.length() / 2; i++) {
			int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
			int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
			result[i] = (byte) (high * 16 + low);
		}
		return result;
	}

}

控制台输出：