加密工具之DES

private static final byte[] iv = { 2, 0, 1, 5, 2, 7, 7, 5 };

	public static final String DECRYPT_KEY = "20170628";

	/**
	 * 加密算法
	 * 
	 * @param encryptString
	 * @param encryptKey
	 * @return
	 * @throws Exception
	 */
	public static String encryptDES(String encryptString, String encryptKey)
			throws Exception {
		IvParameterSpec zeroIv = new IvParameterSpec(iv);
		SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
		byte[] encryptedData = cipher.doFinal(encryptString.getBytes());
		return Base64.encode(encryptedData);
	}

	/**
	 * 解密算法
	 * 
	 * @param decryptString
	 * @param decryptKey
	 * @return
	 * @throws Exception
	 */
	public static String decryptDES(String decryptString, String decryptKey)
			throws Exception {
		byte[] byteMi = Base64.decode(decryptString);
		IvParameterSpec zeroIv = new IvParameterSpec(iv);
		SecretKeySpec key = new SecretKeySpec(decryptKey.getBytes(), "DES");
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
		byte decryptedData[] = cipher.doFinal(byteMi);
		return new String(decryptedData);
	}

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class Base64
{
	private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
			.toCharArray();

	/**
	 * data[]進行編碼
	 * 
	 * @param data
	 * @return
	 */
	public static String encode(byte[] data)
	{
		int start = 0;
		int len = data.length;
		StringBuffer buf = new StringBuffer(data.length * 3 / 2);

		int end = len - 3;
		int i = start;
		int n = 0;

		while (i <= end)
		{
			int d = ((((int) data[i]) & 0x0ff) << 16)
					| ((((int) data[i + 1]) & 0x0ff) << 8)
					| (((int) data[i + 2]) & 0x0ff);

			buf.append(legalChars[(d >> 18) & 63]);
			buf.append(legalChars[(d >> 12) & 63]);
			buf.append(legalChars[(d >> 6) & 63]);
			buf.append(legalChars[d & 63]);

			i += 3;

			if (n++ >= 14)
			{
				n = 0;
				buf.append(" ");
			}
		}

		if (i == start + len - 2)
		{
			int d = ((((int) data[i]) & 0x0ff) << 16)
					| ((((int) data[i + 1]) & 255) << 8);

			buf.append(legalChars[(d >> 18) & 63]);
			buf.append(legalChars[(d >> 12) & 63]);
			buf.append(legalChars[(d >> 6) & 63]);
			buf.append("=");
		}
		else if (i == start + len - 1)
		{
			int d = (((int) data[i]) & 0x0ff) << 16;

			buf.append(legalChars[(d >> 18) & 63]);
			buf.append(legalChars[(d >> 12) & 63]);
			buf.append("==");
		}

		return buf.toString();
	}

	public static byte[] decode(String s)
	{

		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		try
		{
			decode(s, bos);
		}
		catch (IOException e)
		{
			throw new RuntimeException();
		}
		byte[] decodedBytes = bos.toByteArray();
		try
		{
			bos.close();
			bos = null;
		}
		catch (IOException ex)
		{
			System.err.println("Error while decoding BASE64: " + ex.toString());
		}
		return decodedBytes;
	}

	private static void decode(String s, OutputStream os) throws IOException
	{
		int i = 0;

		int len = s.length();

		while (true)
		{
			while (i < len && s.charAt(i) <= ' ')
				i++;

			if (i == len)
				break;

			int tri = (decode(s.charAt(i)) << 18)
					+ (decode(s.charAt(i + 1)) << 12)
					+ (decode(s.charAt(i + 2)) << 6)
					+ (decode(s.charAt(i + 3)));

			os.write((tri >> 16) & 255);
			if (s.charAt(i + 2) == '=')
				break;
			os.write((tri >> 8) & 255);
			if (s.charAt(i + 3) == '=')
				break;
			os.write(tri & 255);

			i += 4;
		}
	}

	private static int decode(char c)
	{
		if (c >= 'A' && c <= 'Z')
			return ((int) c) - 65;
		else if (c >= 'a' && c <= 'z')
			return ((int) c) - 97 + 26;
		else if (c >= '0' && c <= '9')
			return ((int) c) - 48 + 26 + 26;
		else
			switch (c)
			{
				case '+':
					return 62;
				case '/':
					return 63;
				case '=':
					return 0;
				default:
					throw new RuntimeException("unexpected code: " + c);
			}
	}
}