我有一个像这样的哭泣课：
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
* Usage:
*
* String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
* ...
* String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
*
* @author ferenc.hechler
*/
public class SimpleCrypto {
public static String encrypt(String seed, String cleartext) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] result = encrypt(rawKey, cleartext.getBytes());
return toHex(result);
}
public static String decrypt(String seed, String encrypted) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes());
byte[] enc = toByte(encrypted);
byte[] result = decrypt(rawKey, enc);
return new String(result);
}
private static byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(seed);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}
private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return encrypted;
}
private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}
public static String toHex(String txt) {
return toHex(txt.getBytes());
}
public static String fromHex(String hex) {
return new String(toByte(hex));
}
public static byte[] toByte(String hexString) {
int len = hexString.length()/2;
byte[] result = new byte[len];
for (int i = 0; i < len; i++)
result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
return result;
}
public static String toHex(byte[] buf) {
if (buf == null)
return "";
StringBuffer result = new StringBuffer(2*buf.length);
for (int i = 0; i < buf.length; i++) {
appendHex(result, buf[i]);
}
return result.toString();
}
private final static String HEX = "0123456789ABCDEF";
private static void appendHex(StringBuffer sb, byte b) {
sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
}
}
这是我的activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="xmaxsoft.delsifremax.MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="80dp"
android:text="tv1"
android:id="@+id/tv1"
android:background="#120b0b"
android:textColor="#f75555"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="tvText"
android:id="@+id/tvText"
android:background="#120b0b"
android:textColor="#f75555"
android:layout_below="@+id/tv1"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="10dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="tvTextEnc"
android:id="@+id/tvTextEnc"
android:background="#120b0b"
android:textColor="#f75555"
android:layout_below="@+id/tvText"
android:layout_centerHorizontal="true"
android:layout_marginTop="50dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="encrypt"
android:id="@+id/btnEncrypt"
android:layout_below="@+id/tvText"
android:layout_centerHorizontal="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/etPw"
android:layout_below="@+id/tvText"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_toLeftOf="@+id/btnEncrypt"
android:layout_toStartOf="@+id/btnEncrypt"
android:background="#110f0f"
android:paddingTop="10dp"
android:layout_marginTop="10dp"
android:text="etPw"
android:textColor="#28bf25" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Decrypt"
android:id="@+id/btnDecrypt"
android:layout_below="@+id/tvTextEnc"
android:layout_toRightOf="@+id/etPw"
android:layout_toEndOf="@+id/etPw" />
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:text="tvTextDec"
android:id="@+id/tvTextDec"
android:background="#120b0b"
android:textColor="#f75555"
android:layout_below="@+id/btnDecrypt"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>
这是我的MainActivity：
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
public class MainActivity extends AppCompatActivity {
TextView tv1;
TextView tvText;
TextView tvTextEnc;
TextView tvTextDec;
Button btnEncrypt;
Button btnDecrypt;
EditText etPw;
private GoogleApiClient client;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv1 = (TextView) findViewById(R.id.tv1);
tvText = (TextView) findViewById(R.id.tvText);
tvTextEnc = (TextView) findViewById(R.id.tvTextEnc);
tvTextDec = (TextView) findViewById(R.id.tvTextDec);
btnEncrypt = (Button) findViewById(R.id.btnEncrypt);
btnDecrypt = (Button) findViewById(R.id.btnDecrypt);
etPw = (EditText) findViewById(R.id.etPw);
btnEncrypt.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String normalText = tvText.getText().toString().trim();
String normalTextEnc = "";
String seedValue = etPw.getText().toString().trim();
try {
normalTextEnc = SimpleCrypto.encrypt(seedValue,normalText.trim());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
tvTextEnc.setText(normalTextEnc.toString().trim());
}
});
btnDecrypt.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String normalTextEnc = tvTextEnc.getText().toString().trim();
String normalTextDec = "";
String seedValue = etPw.getText().toString().trim();
try {
normalTextDec = SimpleCrypto.decrypt(seedValue, normalTextEnc.trim());
tvTextDec.setText(normalTextDec.toString().trim());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
tvTextDec.setText(e.toString());
}
}
});
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
@Override
public void onStart() {
super.onStart();
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://xmaxsoft.delsifremax/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://xmaxsoft.delsifremax/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
我可以加密字符串，但我无法再次解密加密字符串。为什么？这段代码有什么问题？我得到＆＃34; javax.crypto.BadPaddingException：pad block corrupted＆＃34;错误。
答案 0 :(得分：0)
我有一个使用密码和盐对某些String进行加密和解密的类：
public class Crypto {
private static String IV = "IV_VALUE_16_BYTE";
private static String PASSWORD = "some-hash-password";
private static String SALT = "some-hash-salt";
public static String encryptAndEncode(String raw) {
try {
Cipher c = getCipher(Cipher.ENCRYPT_MODE);
byte[] encryptedVal = c.doFinal(getBytes(raw));
String s = Base64.encodeToString(encryptedVal, Base64.DEFAULT);
return s;
} catch (Throwable t) {
throw new RuntimeException(t);
}
}
public static String decodeAndDecrypt(String encrypted) throws Exception {
byte[] decodedValue = Base64.decode(getBytes(encrypted),Base64.DEFAULT);
Cipher c = getCipher(Cipher.DECRYPT_MODE);
byte[] decValue = c.doFinal(decodedValue);
return new String(decValue);
}
private String getString(byte[] bytes) throws UnsupportedEncodingException {
return new String(bytes, "UTF-8");
}
private static byte[] getBytes(String str) throws UnsupportedEncodingException {
return str.getBytes("UTF-8");
}
private static Cipher getCipher(int mode) throws Exception {
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] iv = getBytes(IV);
c.init(mode, generateKey(), new IvParameterSpec(iv));
return c;
}
private static Key generateKey() throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
char[] password = PASSWORD.toCharArray();
byte[] salt = getBytes(SALT);
KeySpec spec = new PBEKeySpec(password, salt, 65536, 128);
SecretKey tmp = factory.generateSecret(spec);
byte[] encoded = tmp.getEncoded();
return new SecretKeySpec(encoded, "AES");
}
}
加密：
Crypto.encryptAndEncode("String_to_encrypt");
解密：
Crypto.decodeAndDecrypt("String_encrypted");
希望有帮助！