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Base64编码与DES加密解密算法

Base64编码是网络上最常见的用于传输8位字节代码的编码方式之一，可用于在HTTP环境下传递较长的标识信息。其运算原理基于计算机是8位存储的特点，通过将24位字符分解为4组6位的字符进行处理，并为每组高位补0，转换成ascii码后根据RFC2045～RFC2049表进行转换。

Base64编码示例

public class Test {    public static void main(String[] args) throws Exception {        Test test = new Test();        test.testEncrypt();        test.testDecrypt();    }    public void testEncrypt() throws Exception {        String pwd = "123456";        byte[] i = pwd.getBytes();        String input = new BASE64Encoder().encodeBuffer(i);        System.out.println(input);    }    public void testDecrypt() throws Exception {        String pwd = "MTIzNDU2";        byte[] o = new BASE64Decoder().decodeBuffer(pwd);        String output = new String(o);        System.out.println(output);    }}

输出结果

123456的Base64编码为：MTIzNDU2解密后的结果为：123456

DES加密算法

DES（Data Encryption Standard）是一种对称加密算法，加密和解密均使用相同密钥进行处理。

public class DESTest {    public static void main(String[] args) {        DESTest t = new DESTest();        String data = "123456";        String encode_data = t.encode(data);        System.out.println(encode_data);        String decode_data = t.decode(encode_data);        System.out.println(decode_data);    }    public static final String ALGORITHM_DES = "DES";    public static final String SIGN_KEY = "20170313EHR";    public String encode(String data) {        if (data == null) {            return null;        }        try {            String key = SIGN_KEY;            DESKeySpec dks = new DESKeySpec(key.getBytes());            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");            Key secretKey = keyFactory.generateSecret(dks);            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);            cipher.init(Cipher.ENCRYPT_MODE, secretKey);            byte[] bytes = cipher.doFinal(data.getBytes());            return byte2str(bytes);        } catch (Exception e) {            e.printStackTrace();            return data;        }    }    public String decode(String data) {        if (data == null) {            return null;        }        try {            String key = SIGN_KEY;            DESKeySpec dks = new DESKeySpec(key.getBytes());            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");            Key secretKey = keyFactory.generateSecret(dks);            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);            cipher.init(Cipher.DECRYPT_MODE, secretKey);            byte[] bytes = cipher.doFinal(str2byte(data.getBytes()));            return new String(bytes);        } catch (Exception e) {            e.printStackTrace();            return data;        }    }    private static byte[] str2byte(byte[] b) {        if ((b.length % 2) != 0) {            throw new IllegalArgumentException();        }        byte[] b2 = new byte[b.length / 2];        for (int n = 0; n < b.length; n += 2) {            String item = new String(b, n, 2);            b2[n / 2] = (byte) Integer.parseInt(item, 16);        }        return b2;    }    private static String byte2str(byte[] b) {        StringBuilder hs = new StringBuilder();        for (int n = 0; n < b.length; n++) {            String stmp = Integer.toHexString(b[n] & 0xFF);            if (stmp.length() == 1) {                hs.append('0');            }            hs.append(stmp);        }        return hs.toString().toUpperCase();    }}

编码与解密后的结果

• 编码：1730D210F056D4D8123456
• 解密：123456

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