AES 복호화 실례

package com.bijian.study;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

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;

import org.apache.axis.encoding.Base64;

public class AESTools {

	private static String password = "      complex password,          ";

	/**
	 *     
	 */
	public static String getPassword() {
		return password;
	}

	/**
	 *   
	 * @param content
	 * @param password
	 * @return
	 */
	public static byte[] encrypt(String content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
			random.setSeed(getKeyByStr(password));
			kgen.init(128, random);
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");//      
			byte[] byteContent = content.getBytes("UTF-8");
			cipher.init(Cipher.ENCRYPT_MODE, key);//    
			byte[] result = cipher.doFinal(byteContent);
			return 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;
	}

	/**
	 *   
	 * @param content
	 * @param password
	 * @return
	 */
	public static byte[] decrypt(byte[] content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
			random.setSeed(getKeyByStr(password));
			kgen.init(128, random);
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");//      
			cipher.init(Cipher.DECRYPT_MODE, key);//    
			byte[] result = cipher.doFinal(content);
			return result; //   
		} 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;
	}

	public static byte[] getKeyByStr(String str) {
		byte[] bRet = new byte[str.length() / 2];
		for (int i = 0; i < str.length() / 2; i++) {
			Integer itg = new Integer(16 * getChrInt(str.charAt(2 * i)) + getChrInt(str.charAt(2 * i + 1)));
			bRet[i] = itg.byteValue();
		}
		return bRet;
	}

	public static int getChrInt(char chr) {

		int iRet = 0;
		if (chr == "0".charAt(0))
			iRet = 0;
		if (chr == "1".charAt(0))
			iRet = 1;
		if (chr == "2".charAt(0))
			iRet = 2;
		if (chr == "3".charAt(0))
			iRet = 3;
		if (chr == "4".charAt(0))
			iRet = 4;
		if (chr == "5".charAt(0))
			iRet = 5;
		if (chr == "6".charAt(0))
			iRet = 6;
		if (chr == "7".charAt(0))
			iRet = 7;
		if (chr == "8".charAt(0))
			iRet = 8;
		if (chr == "9".charAt(0))
			iRet = 9;
		if (chr == "A".charAt(0))
			iRet = 10;
		if (chr == "B".charAt(0))
			iRet = 11;
		if (chr == "C".charAt(0))
			iRet = 12;
		if (chr == "D".charAt(0))
			iRet = 13;
		if (chr == "E".charAt(0))
			iRet = 14;
		if (chr == "F".charAt(0))
			iRet = 15;
		return iRet;
	}

	public static String decryptString(String contents) {
		return new String(decrypt(Base64.decode(contents), password));
	}

	public static String encryptString(String contents) {
		return Base64.encode(encrypt(contents, password));
	}

	public static void main(String[] args) {

		String text = "     ！Welcome to shenzhen!";
		
		//  
		String encryptStr = AESTools.encryptString(text);
		System.out.println("text length:" + text.length() + ",text:" + text);
		
		System.out.println("encryptStr length:" + encryptStr.length() + ",encryptStr" + encryptStr);
		
		System.out.println("         add length:"	+ (encryptStr.length() - text.length()));
		
		//  
		String decryptStr = AESTools.decryptString(encryptStr);
		System.out.println("decryptStr length:" + decryptStr.length() + ",decryptStr:" + decryptStr);
	}
}

text length:26,text:     ！Welcome to shenzhen!
encryptStr length:64,encryptStrujOEp9losb7mJx8a8Ht2nbCNaVtfCrAuKt9JRjTGdULpPYJOUr0nvzYQ9rvqWB6z
         add length:38
decryptStr length:26,decryptStr:     ！Welcome to shenzhen!