前言
各位同学大家好，最近工作中用到了DES 对称加密 遇到了一些问题所以就总结出来 希望能帮助到各位同学工作和学习，那么废话不多说 DES是比较常见的堆成加密方式
对称加密
对称加密就是公钥好私钥是同一把 加密解密都用这个 与之对应的就是res非堆成加密 我们这边就讲一下对称加密的
具体实现
设置好偏移量 算法 和工作模式 编码
/**
* 偏移变量，固定占8位字节
*/
private final static String IV_PARAMETER = "12345678";
/**
* 密钥算法
*/
private static final String ALGORITHM = "DES";
/**
* 加密/解密算法-工作模式-填充模式
*/
private static final String CIPHER_ALGORITHM = "DES/CBC/PKCS5Padding";
/**
* 默认编码
*/
private static final String CHARSET = "utf-8";
生成key
/**
* 生成key
*
* @param password
* @return
* @throws Exception
*/
private static Key generateKey(String password) throws Exception {
DESKeySpec dks = new DESKeySpec(password.getBytes(CHARSET));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
return keyFactory.generateSecret(dks);
}
加密
/**
* DES加密字符串
*
* @param password 加密密码，长度不能够小于8位
* @param data 待加密字符串
* @return 加密后内容
*/
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
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(Base64.getEncoder().encode(bytes));
}else{
return Base64Utils.encode(bytes);
}
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
image.png
我们加密之后要进行base64编码处理一下但是Android SDK 里面提供的api 只能在android 8.0 api26以上才能使用的 .所以我们要在这里兼容下低版本
低版本android api 26以下 base 64 工具类
package com.example.desdemo;
import java.io.UnsupportedEncodingException;
public class Base64Utils {
private static char[] base64EncodeChars = new char[]
{ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', '+', '/' };
private static byte[] base64DecodeChars = new byte[]
{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29,
30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1,
-1, -1, -1 };
/**
* 加密
*
* @param data
* @return
*/
public static String encode(byte[] data) {
StringBuffer sb = new StringBuffer();
int len = data.length;
int i = 0;
int b1, b2, b3;
while (i < len) {
b1 = data[i++] & 0xff;
if (i == len){
sb.append(base64EncodeChars[b1 >>> 2]);
sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
sb.append("==");
break;
}
b2 = data[i++] & 0xff;
if (i == len) {
sb.append(base64EncodeChars[b1 >>> 2]);
sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
sb.append("=");
break;
}
b3 = data[i++] & 0xff;
sb.append(base64EncodeChars[b1 >>> 2]);
sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
sb.append(base64EncodeChars[b3 & 0x3f]);
}
return sb.toString();
}
/**
* 解密
*
* @param str
* @return
*/
public static byte[] decode(String str) {
try{
return decodePrivate(str);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return new byte[]
{};
}
private static byte[] decodePrivate(String str) throws UnsupportedEncodingException {
StringBuffer sb = new StringBuffer();
byte[] data = null;
data = str.getBytes("US-ASCII");
int len = data.length;
int i = 0;
int b1, b2, b3, b4;
while (i < len){
do {
b1 = base64DecodeChars[data[i++]];
} while (i < len && b1 == -1);
if (b1 == -1)
break;
do {
b2 = base64DecodeChars[data[i++]];
} while (i < len && b2 == -1);
if (b2 == -1)
break;
sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));
do{
b3 = data[i++];
if (b3 == 61)
return sb.toString().getBytes("iso8859-1");
b3 = base64DecodeChars[b3];
} while (i < len && b3 == -1);
if (b3 == -1)
break;
sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));
do {
b4 = data[i++];
if (b4 == 61)
return sb.toString().getBytes("iso8859-1");
b4 = base64DecodeChars[b4];
} while (i < len && b4 == -1);
if (b4 == -1)
break;
sb.append((char) (((b3 & 0x03) << 6) | b4));
}
return sb.toString().getBytes("iso8859-1");
}
}
解密
/**
* DES解密字符串
*
* @param password 解密密码，长度不能够小于8位
* @param data 待解密字符串
* @return 解密后内容
*/
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);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(cipher.doFinal(Base64.getMimeDecoder().decode(data.getBytes(CHARSET))), CHARSET);
}else {
return new String(cipher.doFinal(Base64Utils.decode(data)), CHARSET);
}
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
解密中遇到的坑
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(cipher.doFinal(Base64.getDecoder().decode(data.getBytes(CHARSET))), CHARSET);
}
这是原来写写法
会报出类似这种错误
java.lang.IllegalArgumentException: Input byte array has incorrect ending byte at 40
这是网友的回答
image.png
-
正确的写法 就能正常解开其他语言加密后的字符串
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(cipher.doFinal(Base64.getMimeDecoder().decode(data.getBytes(CHARSET))), CHARSET);
}else {
return new String(cipher.doFinal(Base64Utils.decode(data)), CHARSET);
}
加密文件
/**
* DES加密文件
*
* @param srcFile 待加密的文件
* @param destFile 加密后存放的文件路径
* @return 加密后的文件路径
*/
public static String encryptFile(String password, String srcFile, String destFile) {
if (password== null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
try {
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, generateKey(password), iv);
InputStream is = new FileInputStream(srcFile);
OutputStream out = new FileOutputStream(destFile);
CipherInputStream cis = new CipherInputStream(is, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = cis.read(buffer)) > 0) {
out.write(buffer, 0, r);
}
cis.close();
is.close();
out.close();
return destFile;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
解密文件
/**
* DES解密文件
*
* @param srcFile 已加密的文件
* @param destFile 解密后存放的文件路径
* @return 解密后的文件路径
*/
public static String decryptFile(String password, String srcFile, String destFile) {
if (password== null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
try {
File file = new File(destFile);
if (!file.exists()) {
file.getParentFile().mkdirs();
file.createNewFile();
}
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, generateKey(password), iv);
InputStream is = new FileInputStream(srcFile);
OutputStream out = new FileOutputStream(destFile);
CipherOutputStream cos = new CipherOutputStream(out, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = is.read(buffer)) >= 0) {
cos.write(buffer, 0, r);
}
cos.close();
is.close();
out.close();
return destFile;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
测试
private void initview() {
String s = "你好，HelloWorld！";
// 加密
String s2 = null;
s2 = DESUtil.encrypt("环保NB1233", s);
Log.e(TAG, "环保NB1233:s --- >加密 s2 -- > "+s2);
System.out.println("s2===="+s2);
//解密
String s3 = null;
s3 = DESUtil.decrypt("环保NB1233 -- >解密 ", s2);
Log.e(TAG, "环保NB1233:s --- >加密 s3 --- > "+s3);
System.out.println("s3===="+s3);
}
我们看到日志输出加密解密是可以的
image.png
完整代码
package com.example.desdemo;
import android.os.Build;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
public class DESUtil {
/**
* 偏移变量，固定占8位字节
*/
private final static String IV_PARAMETER = "12345678";
/**
* 密钥算法
*/
private static final String ALGORITHM = "DES";
/**
* 加密/解密算法-工作模式-填充模式
*/
private static final String CIPHER_ALGORITHM = "DES/CBC/PKCS5Padding";
/**
* 默认编码
*/
private static final String CHARSET = "utf-8";
public static void main(String[] args) {
String s = "你好，HelloWorld！";
// 加密
String s2 = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
s2 = encrypt("环保NB1233", s);
}
System.out.println("s2===="+s2);
//解密
String s3 = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
s3 = decrypt("环保NB1233", s2);
}
System.out.println("s3===="+s3);
}
/**
* 生成key
*
* @param password
* @return
* @throws Exception
*/
private static Key generateKey(String password) throws Exception {
DESKeySpec dks = new DESKeySpec(password.getBytes(CHARSET));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
return keyFactory.generateSecret(dks);
}
/**
* DES加密字符串
*
* @param password 加密密码，长度不能够小于8位
* @param data 待加密字符串
* @return 加密后内容
*/
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
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(Base64.getEncoder().encode(bytes));
}else{
return Base64Utils.encode(bytes);
}
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
/**
* DES解密字符串
*
* @param password 解密密码，长度不能够小于8位
* @param data 待解密字符串
* @return 解密后内容
*/
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);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
return new String(cipher.doFinal(Base64.getMimeDecoder().decode(data.getBytes(CHARSET))), CHARSET);
}else {
return new String(cipher.doFinal(Base64Utils.decode(data)), CHARSET);
}
} catch (Exception e) {
e.printStackTrace();
return data;
}
}
/**
* DES加密文件
*
* @param srcFile 待加密的文件
* @param destFile 加密后存放的文件路径
* @return 加密后的文件路径
*/
public static String encryptFile(String password, String srcFile, String destFile) {
if (password== null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
try {
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, generateKey(password), iv);
InputStream is = new FileInputStream(srcFile);
OutputStream out = new FileOutputStream(destFile);
CipherInputStream cis = new CipherInputStream(is, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = cis.read(buffer)) > 0) {
out.write(buffer, 0, r);
}
cis.close();
is.close();
out.close();
return destFile;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
/**
* DES解密文件
*
* @param srcFile 已加密的文件
* @param destFile 解密后存放的文件路径
* @return 解密后的文件路径
*/
public static String decryptFile(String password, String srcFile, String destFile) {
if (password== null || password.length() < 8) {
throw new RuntimeException("加密失败，key不能小于8位");
}
try {
File file = new File(destFile);
if (!file.exists()) {
file.getParentFile().mkdirs();
file.createNewFile();
}
IvParameterSpec iv = new IvParameterSpec(IV_PARAMETER.getBytes(CHARSET));
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, generateKey(password), iv);
InputStream is = new FileInputStream(srcFile);
OutputStream out = new FileOutputStream(destFile);
CipherOutputStream cos = new CipherOutputStream(out, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = is.read(buffer)) >= 0) {
cos.write(buffer, 0, r);
}
cos.close();
is.close();
out.close();
return destFile;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
}
最后总结：
这种DES对称加密在我们实战中用也是比较多的 在这里我就记录一下 文章参考了其他博主 但是那些博客是有缺陷的 在android 8.0下是不能使用的 我这边处理掉了,希望能帮助各位同学工作和学习 。如果觉得文章还不错希望能给我一个star 和转发