SharedPreference에 대한 암호화/복호화

http://www.androidside.com/bbs/board.php?bo_table=B46&wr_id=44823&sca=유용한TIP&point=1

 

sharedPreference를 다들 많이 이용하시죠?

근데 만일 여기에 로그인정보같은 중요한 정보를 저장한다면 위험하겠죠?

루팅된 폰에선 금방 읽을수 있으니까요..

이걸 막을수 있는것이 바로 암호화입니다.

import java.util.Map;

import java.util.Set;

import javax.crypto.Cipher;

import javax.crypto.SecretKey;

import javax.crypto.SecretKeyFactory;

import javax.crypto.spec.PBEKeySpec;

import javax.crypto.spec.PBEParameterSpec;

import android.content.Context;

import android.content.SharedPreferences;

import android.provider.Settings;

import android.util.Base64;

public class ObscuredSharedPreferences implements SharedPreferences {

protected static final String UTF8 = "utf-8";

private static final char[] SEKRIT = "ninelab.co.kr".toCharArray(); // INSERT

// A

// RANDOM

// PASSWORD

// HERE.

// Don't use anything you wouldn't want to

// get out there if someone decompiled

// your app.

protected SharedPreferences delegate;

protected Context context;

public ObscuredSharedPreferences(Context context, SharedPreferences delegate) {

this.delegate = delegate;

this.context = context;

}

public class Editor implements SharedPreferences.Editor {

protected SharedPreferences.Editor delegate;

public Editor() {

this.delegate = ObscuredSharedPreferences.this.delegate.edit();

}

@Override

public Editor putBoolean(String key, boolean value) {

delegate.putString(key, encrypt(Boolean.toString(value)));

return this;

}

@Override

public Editor putFloat(String key, float value) {

delegate.putString(key, encrypt(Float.toString(value)));

return this;

}

@Override

public Editor putInt(String key, int value) {

delegate.putString(key, encrypt(Integer.toString(value)));

return this;

}

@Override

public Editor putLong(String key, long value) {

delegate.putString(key, encrypt(Long.toString(value)));

return this;

}

@Override

public Editor putString(String key, String value) {

delegate.putString(key, encrypt(value));

return this;

}

@Override

public void apply() {

delegate.apply();

}

@Override

public Editor clear() {

delegate.clear();

return this;

}

@Override

public boolean commit() {

return delegate.commit();

}

@Override

public Editor remove(String s) {

delegate.remove(s);

return this;

}

@Override

public android.content.SharedPreferences.Editor putStringSet(

String arg0, Set<String> arg1) {

// TODO Auto-generated method stub

return null;

}

}

public Editor edit() {

return new Editor();

}

@Override

public Map<String, ?> getAll() {

throw new UnsupportedOperationException(); // left as an exercise to the

// reader

}

@Override

public boolean getBoolean(String key, boolean defValue) {

final String v = delegate.getString(key, null);

return v != null ? Boolean.parseBoolean(decrypt(v)) : defValue;

}

@Override

public float getFloat(String key, float defValue) {

final String v = delegate.getString(key, null);

return v != null ? Float.parseFloat(decrypt(v)) : defValue;

}

@Override

public int getInt(String key, int defValue) {

final String v = delegate.getString(key, null);

return v != null ? Integer.parseInt(decrypt(v)) : defValue;

}

@Override

public long getLong(String key, long defValue) {

final String v = delegate.getString(key, null);

return v != null ? Long.parseLong(decrypt(v)) : defValue;

}

@Override

public String getString(String key, String defValue) {

final String v = delegate.getString(key, null);

return v != null ? decrypt(v) : defValue;

}

@Override

public boolean contains(String s) {

return delegate.contains(s);

}

@Override

public void registerOnSharedPreferenceChangeListener(

OnSharedPreferenceChangeListener onSharedPreferenceChangeListener) {

delegate.registerOnSharedPreferenceChangeListener(onSharedPreferenceChangeListener);

}

@Override

public void unregisterOnSharedPreferenceChangeListener(

OnSharedPreferenceChangeListener onSharedPreferenceChangeListener) {

delegate.unregisterOnSharedPreferenceChangeListener(onSharedPreferenceChangeListener);

}

protected String encrypt(String value) {

try {

final byte[] bytes = value != null ? value.getBytes(UTF8)

: new byte[0];

SecretKeyFactory keyFactory = SecretKeyFactory

.getInstance("PBEWithMD5AndDES");

SecretKey key = keyFactory.generateSecret(new PBEKeySpec(SEKRIT));

Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");

pbeCipher.init(

Cipher.ENCRYPT_MODE,

key,

new PBEParameterSpec(Settings.Secure.getString(

context.getContentResolver(),

Settings.System.ANDROID_ID).getBytes(UTF8), 20));

return new String(Base64.encode(pbeCipher.doFinal(bytes),

Base64.NO_WRAP), UTF8);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

protected String decrypt(String value) {

try {

final byte[] bytes = value != null ? Base64.decode(value,

Base64.DEFAULT) : new byte[0];

SecretKeyFactory keyFactory = SecretKeyFactory

.getInstance("PBEWithMD5AndDES");

SecretKey key = keyFactory.generateSecret(new PBEKeySpec(SEKRIT));

Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");

pbeCipher.init(

Cipher.DECRYPT_MODE,

key,

new PBEParameterSpec(Settings.Secure.getString(

context.getContentResolver(),

Settings.System.ANDROID_ID).getBytes(UTF8), 20));

return new String(pbeCipher.doFinal(bytes), UTF8);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public Set<String> getStringSet(String arg0, Set<String> arg1) {

// TODO Auto-generated method stub

return null;

}

}

이 클래스를 정의해주고요..

SharedPreferences mSPref = new ObscuredSharedPreferences(mContext,

mContext.getSharedPreferences(SETTING_TABLE_NAME, 0)); 로 이용하시면 됩니다.

아주 유용할거예욤..

[출처] 안드로이드사이드 - http://www.androidside.com/B46/44823