Welcome!

Mobile IoT Authors: Mehdi Daoudi, Carmen Gonzalez, Kevin Jackson, Plutora Blog, Ruxit Blog

Related Topics: Release Management , Mobile IoT, Microservices Expo, Containers Expo Blog, Agile Computing, @CloudExpo

Release Management : Blog Feed Post

Android Encrypted Databases

Encryption as a security topic is perhaps the weakest link in that community

The Android development community, as might be expected, is a pretty vibrant community with a lot of great contributors helping people out. Since Android is largely based upon Java, there is a lot of skills reusability between the Java client dev community and the Android Dev community.

As I mentioned before, encryption as a security topic is perhaps the weakest link in that community at this time. Perhaps, but since that phone/tablet could end up in someone else’s hands much more easily than your desktop or even laptop, it is something that needs a lot more attention from business developers.

When I set out to write my first complex app for Android, I determined to report back to you from time-to-time about what needed better explanation or intuitive solutions. Much has been done in the realm of “making it easier”, except for security topics, which still rank pretty low on the priority list. So using encrypted SQLite databases is the topic of this post. If you think it’s taking an inordinate amount of time for me to complete this app, consider that I’m doing it outside of work. This blog was written during work hours, but all of the rest of the work is squeezed into two hours a night on the nights I’m able to dedicate time. Which is far from every night.

For those of you who are not developers, here’s the synopsis so you don’t have to paw through code with us: It’s not well documented, but it’s possible, with some caveats. I wouldn’t use this method for large databases that need indexes over them, but for securing critical data it works just fine. At the end I propose a far better solution that is outside the purview of app developers and would pretty much have to be implemented by the SQLite team.

Okay, only developers left? Good.

In my research, there were very few useful suggestions for designing secure databases. They fall into three categories:

  1. Use the NDK to write a variant of SQLite that encrypts at the file level. For most Android developers this isn’t an option, and I’m guessing the SQLite team wouldn’t be thrilled about you mucking about with their database – it serves a lot more apps than yours.
  2. Encrypt the entire SD card through the OS and then store the DB there. This one works, but slows the function of the entire tablet/phone down because you’ve now (again) mucked with resources used by other apps. I will caveat that if you can get your users to do this, it is the currently available solution that allows indices over encrypted data.
  3. Use one of several early-beta DB encryption tools. I was uncomfortable doing this with production systems. You may feel differently, particularly after some of them have matured.

I didn’t like any of these options, so I did what we’ve had to do in the past when a piece of data was so dangerous in the wrong hands it needed encrypting. I wrote an interface to the DB that encrypts and decrypts as data is inserted and removed. In Android the only oddity you won’t find in other Java environments – or you can more easily get around in other Java environments – is filling list boxes from the database. For that I had to write a custom provider that took care of on-the-fly decryption and insertion to the list.

My solution follows. There are a large varieties of ways that you could solve this problem in Java, this one is where I went because

  1. I don’t have a lot of rows for any given table.
  2. The data does not need to be indexed.

If either of these items is untrue for your implementation, you’ll either have to modify this implementation or find an alternate solution.

So first the encryption handler. Note that in this sample, I chose to encode encrypted arrays of bytes as Strings. I do not guarantee this will work for your scenario, and suggest you keep them as arrays of bytes until after decryption. Also note that this sample was built from a working one by obfuscating what the actual source did and making some modifications for simplification of example. It was not tested after the final round of simplification, but should be correct throughout.

package com.company.monitor;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

import android.util.Base64;

public class DBEncryptor {
private static byte[] key;
private static String cypherType = cypherType;

public DBEncryptor(String localPass) {

// save the encoded key for future use
// - note that this keeps it in memory, and is not strictly safe
key = encode(localPass.getBytes()).getBytes();
String keyCopy = new String(key);
while(keyCopy.length() < 16)
keyCopy = keyCopy + keyCopy;

byte keyA[] = keyCopy.getBytes();
if(keyA.length > 16)
key = System.arraycopy(keyA, 0, key, 0, 16);
}

public String encode(byte [] s) {

return Base64.encodeToString(s, Base64.URL_SAFE);
}

public byte[] decode(byte[] s) {
return Base64.decode(s, Base64.URL_SAFE);
}


public byte[] getKey() {
// return a copy of the key.
return key.clone();
}

public String encrypt(String toEncrypt) throws Exception {

//Create your Secret Key Spec, which defines the key transformations
SecretKeySpec skeySpec = new SecretKeySpec(key, cypherType);

//Get the cipher
Cipher cipher = Cipher.getInstance(cypherType);

//Initialize the cipher
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

//Encrypt the string into bytes
byte[ ] encryptedBytes = cipher.doFinal(toEncrypt.getBytes());

//Convert the encrypted bytes back into a string
String encrypted = encode(encryptedBytes);

return encrypted;
}

public String decrypt(String encryptedText) throws Exception {

// Get the secret key spec
SecretKeySpec skeySpec = new SecretKeySpec(key, cypherType);

// create an AES Cipher
Cipher cipher = Cipher.getInstance(cypherType);

// Initialize it for decryption
cipher.init(Cipher.DECRYPT_MODE, skeySpec);

// Get the decoded bytes
byte[] toDecrypt = decode(encryptedText.getBytes());

// And finally, do the decryption.
byte[] clearText = cipher.doFinal(toDecrypt);

return new String(clearText);
}
}

So what we are essentially doing is base-64 encoding the string to be encrypted, and then encrypting the base-64 value using standard Java crypto classes. We simply reverse the process to decrypt a string. Note that this class is also useful if you’re storing values in the Properties file and wish them to be encrypted, since it simply operates on strings.

The value you pass in to create the key needs to be something that is unique to the user or tablet. When it comes down to it, this is your password, and should be treated as such (hence why I changed the parameter name to localPass).

For seasoned Java developers, there’s nothing new on Android at this juncture. We’re just encrypting and decrypting data.

Next it does leave the realm of other Java platforms because the database is utilizing SQLite, which is not generally what you’re writing Java to outside of Android. Bear with me while we go over this class.

The SQLite database class follows. Of course this would need heavy modification to work with your database, but the skeleton is here. Note that not all fields have to be encrypted. You can mix and match, no problems at all. That is one of the things I like about this solution, if I need an index for any reason, I can create an unencrypted field of a type other than blob and index on it.

package com.company.monitor;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DBManagernames extends SQLiteOpenHelper {
public static final String TABLE_NAME = "Map";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_LOCAL = "Local";
public static final String COLUMN_WORLD = "World";


private static int indexId = 0;
private static int indexLocal = 1;
private static int indexWorld = 2;

private static final String DATABASE_NAME = "Mappings.db";
private static final int DATABASE_VERSION = 1;

// SQL statement to create the DB
private static final String DATABASE_CREATE = "create table "
+ TABLE_NAME + "(" + COLUMN_ID
+ " integer primary key autoincrement, " + COLUMN_LOCAL
+ " BLOB not null, " + COLUMN_WORLD +" BLOB not null);";

public DBManagernames(Context context, CursorFactory factory) {
super(context, DATABASE_NAME, factory, DATABASE_VERSION);

}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE);


}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
// Yeah, this isn't implemented in production yet either. It's low on the list, but definitely "on the list"

}

// Assumes DBEncryptor was used to convert the fields of name before calling insert
public void insertToDB(DBNameMap name) {
ContentValues cv = new ContentValues();

cv.put(COLUMN_LOCAL, name.getName().getBytes());
cv.put(COLUMN_WORLD, name.getOtherName().getBytes());

getWritableDatabase().insert(TABLE_NAME, null, cv);
}

// returns the encrypted values to be manipulated with the decryptor.   
public DBNameMap readFromDB(Integer index) {

SQLiteDatabase db = getReadableDatabase();
DBNameMap hnm = new DBNameMap();
Cursor cur = null;
try {
cur = db.query(TABLE_NAME, null, "_id='"+index.toString() +"'", null, null, null, COLUMN_ID);
// cursors connsistently return before the first element. Move to the first.
cur.moveToFirst();
byte[] name = cur.getBlob(indexLocal);
byte [] othername = cur.getBlob(indexWorld);

hnm = new DBNameMap(new String(name), new String(othername), false);
} catch(Exception e) {
System.out.println(e.toString());
// Do nothing - we want to return the empty host name map.
}
return hnm;

}

// NOTE: This routine assumes "String name" is the encrypted version of the string.   
public DBNameMap getFromDBByName(String name) {
SQLiteDatabase db = getReadableDatabase();
Cursor cur = null;
String check = null;
try {
// Note - the production version of this routine actually uses the "where" field to get the correct
// element instead of looping the table. This is here for your debugging use.
cur = db.query(TABLE_NAME, null, null, null, null, null, null);
for(cur.moveToFirst();(!cur.isLast());cur.moveToNext()) {
check = new String(cur.getBlob(indexLocal));
if(check.equals(name))
return new DBNameMap(check, new String(cur.getBlob(indexWorld)), false);

}
if(cur.isLast())
return new DBNameMap();

return new DBNameMap(cur.getString(indexLocal), cur.getString(indexWorld), false);
} catch(Exception e) {
System.out.println(e.toString());
return new DBNameMap();
}

}


// used by our list adapter - coming next in the blog.
public Cursor getCursor() {
try {

return getReadableDatabase().query(TABLE_NAME, null, null, null, null, null, null);
} catch(Exception e) {
System.out.println(e.toString());
return null;
}
}

// This is used in our list adapter for mapping to fields.
public String[] listColumns() {
return new String[] {COLUMN_LOCAL};
}


}

I am not including the DBNameMap class, as it is a simple container that has two string fields and maps one name to another.

Finally, we have the List Provider. Android requires that you populate lists with a provider, and has several base ones to work with. The problem with the SimpleCursorAdapter is that it assumes an unencrypted database, and we just invested a ton of time making the DB encrypted. There are several possible solutions to this problem, and I present the one I chose here. I extended ResourceCursorAdapter and implemented decryption right in the routines, leaving not much to do in the list population section of my activity but to assign the correct adapter.

package com.company.monitor;

import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ResourceCursorAdapter;
import android.widget.TextView;

public class EncryptedNameAdapter extends ResourceCursorAdapter {

private String pw;

public EncryptedHostNameAdapter(Context context, int layout, Cursor c,
boolean autoRequery) {
super(context, layout, c, autoRequery);
}

public EncryptedHostNameAdapter(Context context, int layout, Cursor c,
int flags) {
super(context, layout, c, flags);
}

// This class must know what the encryption key is for the DB before filling the list,
// so this call must be made before the list is populated. The first call after the constructor works.
public void setPW(String pww) {
pw = pww;
}


@Override
public View newView(Context context, Cursor cur, ViewGroup parent) {
LayoutInflater li = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
return li.inflate(R.layout.my_list_entry, parent, false);
}

@Override
public void bindView(View arg0, Context arg1, Cursor arg2) {
// Get an encryptor/decryptor for our data.
DBEncryptor enc = new DBEncryptor(pw);

// Get the TextView we're placing the data into.
TextView tvLocal = (TextView)arg0.findViewById(R.id.list_entry_name);
// Get the bytes from the cursor
byte[] bLocal = arg2.getBlob(arg2.getColumnIndex(DBManagerNames.COLUMN_LOCAL ));
// Convert bytes to a string
String local = new String(bSite);

try {
// decrypt the string
local = enc.decrypt(local);
} catch(Exception e) {
System.out.println(e.toString());

// local holds the encrypted version at this point, fix it.

// We’ll return an empty string for simplicity
local = new String();  
}
tvSite.setText(local);
}

}

The EncryptedNameAdapter can be set as the source for any listbox just like most examples set an ArrayAdapter as the source. Of course, it helps if you’ve put some data in the database first Winking smile.

That’s it for this time. There’s a lot more going on with this project, and I’ll present my solution for SSL certificate verification some time in the next couple of weeks, but for now if you need to encrypt some fields of a database, this is one way to get it done. Ping me on any of the social media outlets or here in the comments if you know of a more elegant/less resource intensive solution, always up for learning more.

And please, if you find an error, it was likely introduced in the transition to something I was willing to throw out here publicly, but let me know so others don’t have problems. I’ve done my best not to introduce any, but always get a bit paranoid if I changed it after my last debug session – and I did to simplify and sanitize.

Read the original blog entry...

More Stories By Don MacVittie

Don MacVittie is founder of Ingrained Technology, A technical advocacy and software development consultancy. He has experience in application development, architecture, infrastructure, technical writing,DevOps, and IT management. MacVittie holds a B.S. in Computer Science from Northern Michigan University, and an M.S. in Computer Science from Nova Southeastern University.

@ThingsExpo Stories
TechTarget storage websites are the best online information resource for news, tips and expert advice for the storage, backup and disaster recovery markets. By creating abundant, high-quality editorial content across more than 140 highly targeted technology-specific websites, TechTarget attracts and nurtures communities of technology buyers researching their companies' information technology needs. By understanding these buyers' content consumption behaviors, TechTarget creates the purchase inte...
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Ge...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry’s single source for the cloud. Fusion’s advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including cloud...
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, will provide a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services ...
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Have you ever noticed how some IT people seem to lead successful, rewarding, and satisfying lives and careers, while others struggle? IT author and speaker Don Crawley uncovered the five principles that successful IT people use to build satisfying lives and careers and he shares them in this fast-paced, thought-provoking webinar. You'll learn the importance of striking a balance with technical skills and people skills, challenge your pre-existing ideas about IT customer service, and gain new in...
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this ca...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business. Though, IoT is far more complex than most firms expected with a majority of IoT projects having failed. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, Chief IoTologist at Wipro, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology portfolios and business models to adopt and leverage IoT. He will delve in...
In the enterprise today, connected IoT devices are everywhere – both inside and outside corporate environments. The need to identify, manage, control and secure a quickly growing web of connections and outside devices is making the already challenging task of security even more important, and onerous. In his session at @ThingsExpo, Rich Boyer, CISO and Chief Architect for Security at NTT i3, will discuss new ways of thinking and the approaches needed to address the emerging challenges of securit...
As cloud adoption continues to transform business, today's global enterprises are challenged with managing a growing amount of information living outside of the data center. The rapid adoption of IoT and increasingly mobile workforce are exacerbating the problem. Ensuring secure data sharing and efficient backup poses capacity and bandwidth considerations as well as policy and regulatory compliance issues.
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions with...
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
It is one thing to build single industrial IoT applications, but what will it take to build the Smart Cities and truly society changing applications of the future? The technology won’t be the problem, it will be the number of parties that need to work together and be aligned in their motivation to succeed. In his Day 2 Keynote at @ThingsExpo, Henrik Kenani Dahlgren, Portfolio Marketing Manager at Ericsson, discussed how to plan to cooperate, partner, and form lasting all-star teams to change the...
What are the new priorities for the connected business? First: businesses need to think differently about the types of connections they will need to make – these span well beyond the traditional app to app into more modern forms of integration including SaaS integrations, mobile integrations, APIs, device integration and Big Data integration. It’s important these are unified together vs. doing them all piecemeal. Second, these types of connections need to be simple to design, adapt and configure...
"I think that everyone recognizes that for IoT to really realize its full potential and value that it is about creating ecosystems and marketplaces and that no single vendor is able to support what is required," explained Esmeralda Swartz, VP, Marketing Enterprise and Cloud at Ericsson, in this SYS-CON.tv interview at @ThingsExpo, held June 7-9, 2016, at the Javits Center in New York City, NY.
In his General Session at 16th Cloud Expo, David Shacochis, host of The Hybrid IT Files podcast and Vice President at CenturyLink, investigated three key trends of the “gigabit economy" though the story of a Fortune 500 communications company in transformation. Narrating how multi-modal hybrid IT, service automation, and agile delivery all intersect, he will cover the role of storytelling and empathy in achieving strategic alignment between the enterprise and its information technology.