java DES加密

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.security.MessageDigest;
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";

/**
* 生成key
*
* @param password
* @return
* @throws Exception
*/
private static Key generateKey(String password) throws Exception {
MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
messageDigest.update(password.getBytes("UTF-8"));
String encodestr = byte2Hex(messageDigest.digest());

DESKeySpec dks = new DESKeySpec(encodestr.getBytes(CHARSET));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
return keyFactory.generateSecret(dks);
}

/**
* 将byte转为16进制
*
* @param bytes
* @return
*/
private static String byte2Hex(byte[] bytes) {
StringBuffer stringBuffer = new StringBuffer();
String temp = null;
for (int i = 0; i < bytes.length; i++) {
temp = Integer.toHexString(bytes[i] & 0xFF);
if (temp.length() == 1) {
// 1得到一位的进行补0操作
stringBuffer.append("0");
}
stringBuffer.append(temp);
}
return stringBuffer.toString();
}

/**
* 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
return new String(Base64.getEncoder().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);
return new String(cipher.doFinal(Base64.getDecoder().decode(data.getBytes(CHARSET))), 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;
}
}