Android AES Decrypt decrypt(Context context, String encrypted)

Description

decrypt

Declaration

public static String decrypt(Context context, String encrypted)
            throws Exception 

Method Source Code

//package com.java2s;

import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import android.content.Context;
import android.content.pm.PackageManager;

import android.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;

public class Main {
    public static String decrypt(Context context, String encrypted)
            throws Exception {
        SecretKey skeySpec = generateKey(getSeed(context),
                "edu.uoc.esquelet.app".getBytes());
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decordedValue = Base64.decode(encrypted.getBytes(),
                Base64.DEFAULT);//from  w  ww .ja v  a2 s. co m
        byte[] decValue = cipher.doFinal(decordedValue);
        String decryptedValue = new String(decValue);
        return new String(Base64.decode(decryptedValue, Base64.DEFAULT));
    }

    public static SecretKey generateKey(char[] passphraseOrPin, byte[] salt)
            throws NoSuchAlgorithmException, InvalidKeySpecException {

        final int iterations = 1000;

        final int outputKeyLength = 128;

        SecretKeyFactory secretKeyFactory = SecretKeyFactory
                .getInstance("PBKDF2WithHmacSHA1");
        KeySpec keySpec = new PBEKeySpec(passphraseOrPin, salt, iterations,
                outputKeyLength);
        return secretKeyFactory.generateSecret(keySpec);
    }

    private static char[] getSeed(Context context) {
        long installed = 0;
        try {
            installed = context.getPackageManager().getPackageInfo(
                    "edu.uoc.esquelet.app", 0).firstInstallTime;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return Long.toString(installed).toCharArray();
    }
}

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4. aesDecode(String seed, String encrypted)
5. decrypt(byte[] raw, byte[] encrypted)
6. decrypt(Context context, String encrypted)
7. decode(String seed, String encrypted)
8. decrypt(byte[] raw, byte[] encrypted)
9. decryptedData(String userkey, String encryptedData)