Android端3DES加密

加密感腳好高大上，直接複製代碼。

public class Constants
{
    // 密鑰
    public final static String secretKey = "0535YANTAIJIANWANZHONG99";
    // 向量
    public final static String iv = "12345678";
    // 加解密統一使用的編碼方式
    public final static String encoding = "utf-8";
    // 3des加密
    public static final String algorithm = "desede";

}

加密Util

public class EncodeUtil
{
    /**
     * @param str 需要加密的文字
     * @return 加密後的文字
     * @throws Exception 加密失敗
     */
    public static String get3DES(final String str) throws Exception
    {
        Key deskey = null;
        DESedeKeySpec spec = new DESedeKeySpec(Constants.secretKey.getBytes());
        SecretKeyFactory keyfactory = SecretKeyFactory
                .getInstance(Constants.algorithm);
        deskey = keyfactory.generateSecret(spec);

        Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
        IvParameterSpec ips = new IvParameterSpec(Constants.iv.getBytes());
        cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
        byte[] encryptData = cipher.doFinal(str.getBytes(Constants.encoding));
        return Base64.encode(encryptData);
    }

    /** 
     * 3DES解密 
     *  
     * @param encryptText 加密文本 
     * @return 
     * @throws Exception 
     */  
    public static String decode3DES(String encryptText) throws Exception {  
        Key deskey = null;  
        DESedeKeySpec spec = new DESedeKeySpec(Constants.secretKey.getBytes());  
        SecretKeyFactory keyfactory = SecretKeyFactory.getInstance(Constants.algorithm);  
        deskey = keyfactory.generateSecret(spec);  
        Cipher cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");  
        IvParameterSpec ips = new IvParameterSpec(Constants.iv.getBytes());  
        cipher.init(Cipher.DECRYPT_MODE, deskey, ips);  

        byte[] decryptData = cipher.doFinal(Base64.decode(encryptText));  

        return new String(decryptData, Constants.encoding);  
    } 
}

加密中還需要一個Base64類

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

    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();
    }

    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);
            }
    }

    /**
     * Decodes the given Base64 encoded String to a new byte array. The byte
     * array holding the decoded data is returned.
     */

    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;
        }
    }

}