几种加密解密的方法（仅代码）

1.Base64

编码：

byte[] encode = Base64.encode(str.getBytes(), Base64.DEFAULT);
new String(encode)

解码：

byte[] decode = Base64.decode(result, Base64.DEFAULT);

new String(decode)

2.URLEncoder

编码：

String encode = URLEncoder.encode(content, "UTF-8");

解码：

String decode = URLDecoder.decode(result, "UTF-8");

3.
Des

加密：
try {    // 初始化 设置加密解密的类型    Cipher cipher = Cipher.getInstance("DES");    // 初始化密码    SecretKeySpec keySpec = new SecretKeySpec(str.getBytes(),"DES");    try {        //设置此次操作是加密还是解密        cipher.init(Cipher.ENCRYPT_MODE,keySpec);        // 加密        final byte[] finalResult = cipher.doFinal(password.getBytes());        //经过base64处理避免出现乱码情况        byte[] encode = Base64.encode(finalResult, Base64.DEFAULT);        String result = new String(encode);           } catch (InvalidKeyException e) {        e.printStackTrace();    } catch (BadPaddingException e) {        e.printStackTrace();    } catch (IllegalBlockSizeException e) {        e.printStackTrace();    }} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();}
解密：
try {    Cipher cipherDecode = Cipher.getInstance("DES");    SecretKeySpec spec = new SecretKeySpec(password.getBytes(),"DES");    cipherDecode.init(Cipher.DECRYPT_MODE,spec);    // 获取textView加密后的结果    byte[] decode = Base64.decode(result, Base64.DEFAULT);    byte[] doFinal = cipherDecode.doFinal(decode);    String result = new String(doFinal);} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();} catch (InvalidKeyException e) {    e.printStackTrace();} catch (BadPaddingException e) {    e.printStackTrace();} catch (IllegalBlockSizeException e) {    e.printStackTrace();}
4.Aes

加密：
try {    // 初始化 设置加密解密的类型    Cipher cipher = Cipher.getInstance("AES");    // 初始化密码    SecretKeySpec keySpec = new SecretKeySpec(password.getBytes(),"AES");    try {        //设置此次操作是加密还是解密        cipher.init(Cipher.ENCRYPT_MODE,keySpec);        // 加密        final byte[] finalResult = cipher.doFinal(str.getBytes());        //经过base64处理避免出现乱码情况        byte[] encode = Base64.encode(finalResult, Base64.DEFAULT);        String result = new String(encode);    } catch (InvalidKeyException e) {        e.printStackTrace();    } catch (BadPaddingException e) {        e.printStackTrace();    } catch (IllegalBlockSizeException e) {        e.printStackTrace();    }} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();}

解密：
try {    Cipher cipherDecode = Cipher.getInstance("AES");    SecretKeySpec spec = new SecretKeySpec(passwords.getBytes(),"AES");    cipherDecode.init(Cipher.DECRYPT_MODE,spec);    // 获取textView加密后的结果    byte[] decode = Base64.decode(result, Base64.DEFAULT);    byte[] doFinal = cipherDecode.doFinal(decode);    String result = new String(doFinal);} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();} catch (InvalidKeyException e) {    e.printStackTrace();} catch (BadPaddingException e) {    e.printStackTrace();} catch (IllegalBlockSizeException e) {    e.printStackTrace();}
5.RSA

private PublicKey mPublicKey;private PrivateKey mPrivateKey;
//生成公钥和密钥
try {    // 初始化密码对生成器    KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");    // 设置密码的长度    generator.initialize(1024);    // 生成密码对    KeyPair keyPair = generator.generateKeyPair();    // 获取公钥    mPublicKey = keyPair.getPublic();    //获取私钥    mPrivateKey = keyPair.getPrivate();    //////////////////////////把私钥存储String到本地//////////////////////////////    byte[] mPrivateKeyEncoded = mPrivateKey.getEncoded();    byte[] encode = Base64.encode(mPrivateKeyEncoded, Base64.DEFAULT);    String key = new String(encode);    SharedPreferences sp = getSharedPreferences("day02", Context.MODE_PRIVATE);    SharedPreferences.Editor edit = sp.edit();    edit.putString("privateKey",key);    edit.commit();} catch (NoSuchAlgorithmException e) {    e.printStackTrace();}
加密：
try {
    Cipher cipher = Cipher.getInstance("RSA");    // 设置加密或者解密模式 ，传入公钥    cipher.init(Cipher.ENCRYPT_MODE,mPublicKey);    byte[] encode = cipher.doFinal(content.getBytes());    byte[] bytes = Base64.encode(encode, Base64.DEFAULT);    String result = new String(bytes);} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();} catch (InvalidKeyException e) {    e.printStackTrace();} catch (BadPaddingException e) {    e.printStackTrace();} catch (IllegalBlockSizeException e) {    e.printStackTrace();}
解密：
String result = mTextView.getText().toString();byte[] decode = Base64.decode(result, Base64.DEFAULT);try {    Cipher ciphers = Cipher.getInstance("RSA");    ciphers.init(Cipher.DECRYPT_MODE,mPrivateKey);    byte[] bytes = ciphers.doFinal(decode);    String result = new String(bytes);} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();} catch (InvalidKeyException e) {    e.printStackTrace();} catch (BadPaddingException e) {    e.printStackTrace();} catch (IllegalBlockSizeException e) {    e.printStackTrace();}
通过服务器给我们的字符串来解密
// 1 通过字符串生成私钥    SharedPreferences sharedPreferences = getSharedPreferences("wenjian", Context.MODE_PRIVATE);    String stringKey = sharedPreferences.getString("privateKey", "");    if (TextUtils.isEmpty(stringKey)){        Log.d("TAG", "onClick: 私钥没有存成功");        return;    }else {        Log.d("TAG", "onClick: StringKey  == "+stringKey);    }    //因为我们存私钥的经过Base64编码过，所以我们必须解码回去    byte[] bytesKey = Base64.decode(stringKey, Base64.DEFAULT);    // 通过byte数组生成公钥或者私钥    PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(bytesKey);    KeyFactory factory = KeyFactory.getInstance("RSA");    PrivateKey privateKey = factory.generatePrivate(spec);    // 2 解密    Cipher cipher = Cipher.getInstance("RSA");    cipher.init(Cipher.DECRYPT_MODE,privateKey);    byte[] decode = Base64.decode(result, Base64.DEFAULT);    byte[] doFinal = cipher.doFinal(decode);    mTextView.setText(new String(doFinal));    isEncode = false;} catch (NoSuchAlgorithmException e) {    e.printStackTrace();} catch (NoSuchPaddingException e) {    e.printStackTrace();} catch (InvalidKeyException e) {    e.printStackTrace();} catch (BadPaddingException e) {    e.printStackTrace();} catch (IllegalBlockSizeException e) {    e.printStackTrace();} catch (InvalidKeySpecException e) {    e.printStackTrace();}

6.MD5摘要
//摘要try {    // 初始化    MessageDigest digest = MessageDigest.getInstance("MD5");    //指定 byte数组来进行摘要    digest.update(str.getBytes());    // 获取摘要的结果    byte[] results = digest.digest();    // 创建Buffer来累加字符串    StringBuffer buffer = new StringBuffer();    for (int i = 0; i < results.length; i++) {        byte result = results[i];        // 把得到结果 传化成16进制的字符串        String s = Integer.toHexString(result & 0xFF);        if (s.length() == 1) {            buffer.append("0");        }        buffer.append(s);    }    String result = buffer.toString();} catch (NoSuchAlgorithmException e) {    e.printStackTrace();}
7.
Sha1
//摘要try {    // 初始化    MessageDigest digest = MessageDigest.getInstance("SHA1");    //指定 byte数组来进行摘要    digest.update(content.getBytes());    // 获取摘要的结果    byte[] results = digest.digest();    // 创建Buffer来累加字符串    StringBuffer buffer = new StringBuffer();    for (int i = 0; i < results.length; i++) {        byte result = results[i];        // 把得到结果 传化成16进制的字符串        String s = Integer.toHexString(result & 0xFF);        //        if (s.length()==1){            buffer.append("0");        }        buffer.append(s);    }    String result = buffer.toString();} catch (NoSuchAlgorithmException e) {    e.printStackTrace();}

这里仅仅是几种加密解密的代码，具体介绍有时间再做，基本也就这么多东西，能用就行了。