android对字符串的加密和解密方法
import java.security.Key;
import java.security.Security;
import javax.crypto.Cipher;
public class DesUtils {
private static String strDefaultKey = "national";
private Cipher encryptCipher = null;
private Cipher decryptCipher = null;
public static String byteArr2HexStr(byte[] arrB) throws Exception {
int iLen = arrB.length;
// 每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍
StringBuffer sb = new StringBuffer(iLen * 2);
for (int i = 0; i < iLen; i++) {
int intTmp = arrB[i];
// 把负数转换为正数
while (intTmp < 0) {
intTmp = intTmp + 256;
}
// 小于0F的数需要在前面补0
if (intTmp < 16) {
sb.append("0");
}
sb.append(Integer.toString(intTmp, 16));
}
return sb.toString();
}
public static byte[] hexStr2ByteArr(String strIn) throws Exception {
byte[] arrB = strIn.getBytes();
int iLen = arrB.length;
// 两个字符表示一个字节，所以字节数组长度是字符串长度除以2
byte[] arrOut = new byte[iLen / 2];
for (int i = 0; i < iLen; i = i + 2) {
String strTmp = new String(arrB, i, 2);
arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
}
return arrOut;
}
public DesUtils() throws Exception {
this(strDefaultKey);
}
public DesUtils(String strKey) {
// Security.addProvider(null);
Key key;
try {
key = getKey(strKey.getBytes());
encryptCipher = Cipher.getInstance("DES");
encryptCipher.init(Cipher.ENCRYPT_MODE, key);
decryptCipher = Cipher.getInstance("DES");
decryptCipher.init(Cipher.DECRYPT_MODE, key);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public byte[] encrypt(byte[] arrB) throws Exception {
return encryptCipher.doFinal(arrB);
}
public String encrypt(String strIn) throws Exception {
return byteArr2HexStr(encrypt(strIn.getBytes()));
}
public byte[] decrypt(byte[] arrB) throws Exception {
return decryptCipher.doFinal(arrB);
}
public String decrypt(String strIn) throws Exception {
return new String(decrypt(hexStr2ByteArr(strIn)));
}
private Key getKey(byte[] arrBTmp) throws Exception {
// 创建一个空的8位字节数组（默认值为0）
byte[] arrB = new byte[8];
// 将原始字节数组转换为8位
for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
arrB[i] = arrBTmp[i];
}
// 生成密钥
Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
return key;
}
public static void main(String[] args) {
try {
String test = "liwc";
//注意这里，自定义的加密的KEY要和解密的KEY一致，这就是钥匙，如果你上锁了，却忘了钥匙，那么是解密不了的
DesUtils des = new DesUtils("leemenz");//自定义密钥
System.out.println("加密前的字符：" + test);
System.out.println("加密后的字符：" + des.encrypt(test);
System.out.println("解密后的字符：" + des.decrypt(des.encrypt(test)));
}
catch (Exception e) {
e.printStackTrace();
}
}
}