base64 加密， 这个其实不可以算作加密方法，它可以看作是一种编码方式，它的用途只是二进制数字和字符串进行相互转化。
base64是网络上最常见的用于传输 8Bit字节码的编码方式之一，是一种基于64个可打印字符来表示二进制数据的方法。base64一般用于在 HTTP协议下传输二进制数据，由于 HTTP协议是文本协议，所以在 HTTP协议下传输二进制数据需要将二进制数据转换为字符数据。然而直接转换是不行的。因为网络传输只能传输可打印字符。
MD5加密 散列函数计算，一种不安全的加密算法，通常用于账号密码的加密，但是一般都需要加盐处理，单纯的MD5的加密后的字符串可以被破解，或者通过字典查出。
java 实现base64加解密：
//base64 加解密
//编码加密
String encodeStr = base64.getEncoder().encodeToString(str.getBytes("UTF-8"));
System.out.println("base64加密后的字符串为:" + encodeStr);
//解码解密
String decoderStr = new String(base64.getDecoder().decode(encodeStr), StandardCharsets.UTF_8); //
// 推荐使用StandardCharsets类指定
System.out.println("base64解密后的字符串为" + decoderStr);
对称加密算法：DES、AES
DES算法加密的安全等级相对较低，通过同一个密钥进行加密解密。
Java实现DES加解密
private final static String IV_PARAMETER = "12345678";
private static final String ALGORITHM = "DES";
private static final String CIPHER_ALGORITHM = "DES/CBC/PKCS5Padding";
private static final String CHARSET = "utf-8";
private static Key generateKey(String password) throws Exception {
DESKeySpec dks = new DESKeySpec(password.getBytes(CHARSET));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
return keyFactory.generateSecret(dks);
}
public static String encrypt(String password, String data) {
if (password == null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
if (data == null) {
return null;
}
try {
Key secretKey = generateKey(password);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
byte[] bytes = cipher.doFinal(data.getBytes(CHARSET));
//JDK1.8及以上可直接使用base64，JDK1.7及以下可以使用base64Encoder
//Android平台可以使用android.util.base64
return new String(base64.getEncoder().encode(bytes));
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
public static String decrypt(String password, String data) {
if (password == null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
if (data == null) {
return null;
}
try {
Key secretKey = generateKey(password);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);
return new String(cipher.doFinal(base64.getDecoder().decode(data.getBytes(CHARSET))), CHARSET);
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
public static void main(String[] args) throws UnsupportedEncodingException {
String str = "hello base64 啊啊ADCDEFG";
//DES加解密
String password = "abcDEF123";//默认的密钥，根据情况修改
String encodeStrDes = encrypt(password, str);
System.out.println("DES 加密后的字符串为： " + encodeStrDes);
String decodeStrDes = decrypt(password, encodeStrDes);
System.out.println("DES 解密后的字符串为： " + decodeStrDes);
}
AES加密是一种安全性质比较高的加密算法，可以用作敏感数据的加密。从下图可以看到，AES对加密用的密钥都多次进行了轮转换，
Java实现AES加解密
private static final String CHARSET = "utf-8";
private static final String DEFAULT_CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";
private static final String FILL_VECTOR = "1234560405060708";
private static final String ENCODING = "GBK";
private static final String KEY_ALGORITHM = "AES";
public static String encryptAES(String content, String password) {
if (StringUtils.isAnyEmpty(content, password)) {
return null;
}
byte[] raw = hex2byte(password);
SecretKeySpec skeySpec = new SecretKeySpec(raw, KEY_ALGORITHM);
Cipher cipher = null;
try {
cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
IvParameterSpec iv = new IvParameterSpec(FILL_VECTOR.getBytes());
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] anslBytes = content.getBytes(ENCODING);
byte[] encrypted = cipher.doFinal(anslBytes);
return byte2hex(encrypted).toUpperCase();
} catch (Exception e) {
}
return null;
}
public static String decryptAES(String content, String password) {
if (StringUtils.isAnyEmpty(content, password)) {
return null;
}
try {
byte[] raw = hex2byte(password);
SecretKeySpec skeySpec = new SecretKeySpec(raw, KEY_ALGORITHM);
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
IvParameterSpec iv = new IvParameterSpec(FILL_VECTOR.getBytes());
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] encrypted1 = hex2byte(content);
byte[] original = cipher.doFinal(encrypted1);
return new String(original, ENCODING);
} catch (Exception e) {
}
return null;
}
public static byte[] hex2byte(String strhex) {
if (strhex == null) {
return null;
}
int l = strhex.length();
if (l % 2 == 1) {
return null;
}
byte[] b = new byte[l / 2];
for (int i = 0; i != l / 2; i++) {
b[i] = (byte) Integer.parseInt(strhex.substring(i * 2, i * 2 + 2), 16);
}
return b;
}
public static String byte2hex(byte[] b) {
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (java.lang.Integer.toHexString(b[n] & 0xFF));
if (stmp.length() == 1) {
hs = hs + "0" + stmp;
} else {
hs = hs + stmp;
}
}
return hs.toUpperCase();
}
public static void main(String[] args) throws UnsupportedEncodingException {
String str = "hello base64 啊啊ADCDEFG";
//AES加解密
//必须为16位
String key = "9230967890982316";
//生成加密密钥
String key2 = byte2hex(key.getBytes());
System.out.println(key2);
String encryptStr = encryptAES(str, key2);
System.out.println(encryptStr);
System.out.println(decryptAES(encryptStr, key2));
}
RSA加密。典型的不对称加密算法，存在公钥和私钥。因为存在大量的运算，所以加解密的耗时会比对称加密算法更长。
