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@aliab
Created September 9, 2014 10:47
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this is java class for encrypt/decrypt any Android resource, o bye[] file
package net.appersian.android.wod.common;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class Encryptor {
public static byte[] generateKey(String password) throws Exception
{
byte[] keyStart = password.getBytes("UTF-8");
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
sr.setSeed(keyStart);
kgen.init(128, sr);
SecretKey skey = kgen.generateKey();
return skey.getEncoded();
}
public static byte[] encodeFile(byte[] key, byte[] fileData) throws Exception
{
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(fileData);
return encrypted;
}
public static byte[] decodeFile(byte[] key, byte[] fileData) throws Exception
{
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(fileData);
return decrypted;
}
}
package net.appersian.android.wod.common;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.http.util.ByteArrayBuffer;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
public class EncryptorHelper {
public static byte[] encrypt(Context ctx,int resource,String pswd) throws Exception{
InputStream is = ctx.getResources().openRawResource(resource);
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
int current = 0;
try {
while ((current = bis.read()) != -1) {
baf.append((byte) current);
}
} catch (IOException e) {
e.printStackTrace();
}
byte[] b = baf.toByteArray();
byte[] filesBytes = null;
byte[] yourKey = null;
yourKey = Encryptor.generateKey(pswd);
filesBytes = Encryptor.encodeFile(yourKey, b);
return filesBytes;
}
public static byte[] decrypt(Context ctx,int resource,String pswd) throws Exception{
InputStream is = ctx.getResources().openRawResource(resource);
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
int current = 0;
try {
while ((current = bis.read()) != -1) {
baf.append((byte) current);
}
} catch (IOException e) {
e.printStackTrace();
}
byte[] b = baf.toByteArray();
byte[] filesBytes = null;
byte[] yourKey = null;
yourKey = Encryptor.generateKey(pswd);
filesBytes = Encryptor.decodeFile(yourKey, b);
return filesBytes;
}
public static Bitmap bitmapDecrypt(Context ctx,int resource,String pswd) throws Exception{
byte[] b = decrypt(ctx, resource, pswd);
return getBitmap(b);
}
public static BitmapDrawable drawableDecrypt(Context ctx,int resource,String pswd,Resources res) throws Exception{
return new BitmapDrawable(res, bitmapDecrypt(ctx,resource,pswd));
}
public static Bitmap getBitmap(byte[] b){
return BitmapFactory.decodeByteArray(b, 0, b.length);
}
}
@juanEdukathe
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What do you mean by resource into decrypt and encrypt methods?

@aliab
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aliab commented Apr 11, 2021

What do you mean by resource into decrypt and encrypt methods?

It's pretty old but what I remember is this resource int is the id from R file.

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