Java對稱加密算法之AES

【AES】

一種對稱加密算法，DES的取代者。

加密相關文章見：Java加密技術

【代碼】

import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.util.encoders.Hex;

/**
 * 功能：AES加密解密工具類
 * @date : 2016-01-27
 */
public class AesUtil {

	/**
	 * 對密碼進行解密操作
	 * @param strPlain 密文
	 * @param key 解密密鑰
	 * @return
	 */
	public static String decrypt(String strPlain,String key){
		BufferedBlockCipher cipher = new BufferedBlockCipher(new AESEngine());
		CipherParameters param = new KeyParameter(Hex.decode(key));
		cipher.init(false, param);
		byte[] output = Hex.decode(strPlain);
		byte[] out = new byte[output.length];
        int len2 = cipher.processBytes(output, 0, output.length, out, 0);
        try {
			cipher.doFinal(out, len2);
			return new String(out);
		} catch (DataLengthException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalStateException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InvalidCipherTextException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "";
	}

	/**
	 * 對密碼進行加密操作
	 * @param password
	 * @param key
	 * @return
	 */
	public static String encrypt(String password,String key){
		BufferedBlockCipher cipher = new BufferedBlockCipher(new AESEngine());
		CipherParameters    param = new KeyParameter(Hex.decode(key));//key
		byte[]  input =password.getBytes();
		byte[]  out = new byte[input.length];
		cipher.init(true, param);
		int len1 = cipher.processBytes(input, 0, input.length, out, 0);
        try {
			cipher.doFinal(out, len1);
			String str = new String(Hex.encode(out));
			return str;
		} catch (DataLengthException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalStateException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InvalidCipherTextException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "";
	}

	/**
	 * 對密碼進行加0操作
	 * @param password
	 * @return
	 */
	public static String addzero(String password){
		int length = password.length();
		if(length<30){
			for(int i=length;i<30;i++){
				password=password+"0";
			}
		}
		if(length>9){
			password = password + String.valueOf(length);
		}else{
			password = password + "0" + String.valueOf(length);
		}
		//System.out.println(password);
		return password;
	}

	/**
	 * 對密碼進行還原操作，去除之前添加的0
	 * @param password
	 * @return
	 */
	public static String removezero(String password){
		if(!Validators.isNull(password)&&password.length()==32){
			String length = password.substring(30, 32);
			char c = length.charAt(0);
			if(c == '0'){
				length = length.substring(1, 2);
			}
			return password.substring(0, Integer.parseInt(length));
		}
		return "";
	}

}

String password = AesUtil.encrypt(AesUtil.addzero(pwd),HashHelper.MD5Encode(hashKey));//加密

String password = AesUtil.removezero(AesUtil.decrypt(pwd,HashHelper.MD5Encode(key)));// 解密