BOB SHARE

Android Fundamentals

Aapplications are written in the Java programming language
.apk is android package
Dalvik Executable (.dex) run by Dalvik

Each application lives in its own security sandbox
Multi-user Linux system, each application is a different user
Each application a unique Linux user ID
Each process has its own virtual machine

Application Components


Essential building blocks of an Android application
Different point through which the system can enter your application

Four different types of application components


Activities
Services
Content providers
Broadcast receivers

Activities


Represents a single screen with a user interface
Email application might have one activity that shows a list of new emails, another activity to compose an email
Different application can start any one of these activities

Services


Runs in the background
Play music in the background
Another component, such as an activity, can start the service

Content providers


Manages Shared set of application data
File system, an SQLite database, on the web
For eg: users contact information

Broadcast receivers


Responds to system-wide broadcast announcements
For eg: screen has turned off, the battery is low, or a picture was captured
No user interface but may create a status bar notification

The Manifest File
Does number of things
User permissions the application requires
Minimum API Level
Hardware and software features
API libraries the application needs

<?xml version="1.0" encoding="utf-8"?>
<manifest ... >
    <application android:icon="@drawable/app_icon.png" ... >
        <activity android:name="com.example.project.ExampleActivity"
                  android:label="@string/example_label" ... >
        </activity>
        ...
    </application>
</manifest>

Application Resources
Composed of more than just code,  images, audio files etc
animations, menus, styles, colors, layout with XML
Different language, device etc

Data Liberation Front

We insert our data in 3rd party service
For eg: email, documents and pictures
As our data grows we become tied to 3rd party service

Imagine this, thousands of emails in your mailbox but dont like the service.
If you switch the mail provider you lose access to thousands of emails
Else stuck with the bad provider
Its just like not being able to take your belongings from the apartment you have leased

Data Liberation Front


Users should be able to control the data they store in any of Googles products.
Goal is to make it easier to move data in and out.
Designed to help you liberate your data from any Google service with as little pain as possible
Youre not locked into Gmail, for example, just because all your old email is there.

Three questions before starting to use a product that will store their data:
Can I get my data out in an open, interoperable, portable format?
How much is it going to cost to get my data out?
How much of my time is it going to take to get my data out?
The ideal answers to these questions are:
Yes.
Nothing more than Im already paying.
As little as possible.

Currently supports export of data in:
Buzz
Contacts
Google+ Stream
Picasa Web Albums
Profiles
Voice

Data Liberation Front
BOD, Eric Schmidt at that time CEO of Google
“How do you be big without being evil?  We dont trap end users. So if you dont like Google, if for whatever reason we do a bad job for you, we make it easy for you to move to our competitor.”
Limitation
Work in progress
Doesnt support all products
No support of import of data

Download the ppt slides for Data Liberation Front presentation from here.

Securing Data With Truecrypt

Objectives

Why Secure and how to
What is encryption
Why encrypt
Truecrypt
Disadvantages of encryption

Why secure data


In the electronic age, information that could otherwise benefit or educate a group or individual can also be used against such groups or individuals.
A letter to your girlfriend may result in a letter from your wifes lawyer.

How to secure data


Hiding
Authenticating
Password and Security
Locking
Destroying
Steganography
Law
Changing form(encryption)‏

What is encryption?


Encryption is the conversion of data into a form, called a cipher text, that cannot be easily understood by unauthorized people.
Encryption is the process of transforming information using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key.

Simple email

Hello bad guy,

I am giving you a valuable information regarding my company. With that information you can ruin my company.

Regards,
Unaware Employee

Encrypted email
�韨Á¤ ␤W ¦1≤¼ôÓ[Œ┌LS†Y␌¬üT†O─Œ¾␌YÓ7¤Þ]”ð°T¼“B◆ÜÊ‹┘‹EâÉ┐Ñ,␌<ÁÜÀ⎻¢²P┤Bž¯<ŒŒƒÉ»┴)û
           ßàÇ┼┬ÀN.‹ÁúÍ[≠–ÎQ©íÎ▒ŠQä ù-™Z"ghë8¹⎼=Ր˵™Ø.─5]ÂÀ⎽×Ϗ┬%(;F›MJ¹âZπ␤ ¿‡æE-= ¶ÒÊïž•"┤9
  ┴┬└┌⎼ÕŽÃð<L £6Å3┘óB”®ÈïXI
␋3þóéÔSKžï┐Ü┬ô▒ýŒ,Ʊ┌ùD±ÃÜ≥▒
Ü‚“€*,QÉ                      ž£6Ù¼ËZ=_-ÒÔ¡*NGY=ƒÜ›„ü/VV─

We need tool so that we cay easily encrypt and decrypt our data
Many commercial and free version available
Built in technology in OS
T r u e C r y p t is free open-source disk encryption software for  Linux, Mac and Windows.


Features of Truecrypt


Creates a virtual encrypted disk within a file and mounts it as a real disk.
Encrypts an entire partition or storage device such as USB flash drive or hard drive.
Encryption is automatic, real-time (on-the-fly) and transparent

Main Features


Provides two levels of plausible deniability, in case an adversary forces you to reveal the password:
1) No TrueCrypt volume can be identified
2) Hidden volume (steganography)   and hidden operating system.

• Standard Truecrypt volume
• Hidden volume

Truecrypt can be found at http://www.truecrypt.org/
Truecrypt tutorial can be found athttp://www.truecrypt.org/docs/?s=tutorial http://www.truecrypt.org/docs/

Disadvantages of encryption


Extra processing
Slow access to data
Extra memory consumed
Data can be rendered useless if the key is lost
Forceful retrieve of key makes encryption useless

Question
?

Download the ppt slides for Securing Data With Truecrypt presentation from here.

IPv4 and Addressing

Introduction


Your introduction here

Objectives


Learn about IP address
Learn about IP allocation
Concept of public and private IP
Concept of loopback IP
Concept of Network and Broadcast ID

Learn about IP address


IP (Internet protocol) is numeric identification of  device in computer network.
Every device in computer network has a unique IP address.
IP is 32 bit long.
Binary but represented as decimal
Separated by . in four octets.
Example of IP address
00000100.00000010.00000010.00000010
is an example of IP address in binary form.
Notice . in every octet
4.2.2.2 is the same IP address in human readable decimal form. (dot-decimal notation)
116.197.164.1, 202.63.242.6, 10.10.5.211 are other examples.
74.125.45.100 is one of the IP of google.com

IP allocation


Originally, an IP address was divided into two parts:
Host and Network
Only 256 Network possible with this allocation
To overcome this problem IP allocated as classful Network
Allocated as CIDR
Classful Network
IP address divided into five class.
Class A,B,C,D and E
Each class defines size of the network and type(unicast or multicast).
In each network there is 2N-2 host address available where N is number of bits for host part.
IP with all bits 0 and all bits 1 cant be used for hosts.
Replace by CIDR from 1993.

CIDR


Classless Inter-Domain Routing
Main problem of classful network - too small for most enterprises, and the next larger block contained 65,536 addresses—too large to be used efficiently by even large organizations
Uses CIDR notation to specify IP address.
134.13.1.0/21 example of CIDR notation

Public and Private IP


Private IP addresses are unroutable address
Private IP address are not globally assigned
Private IP addresses created due to shortage of public IP
One IP range in class A,B and C separated as private IP
Private IP cant be used in Internet
Private IP
Localhost
address range 127.0.0.0–127.255.255.255
Packets sent to this address returns to the same interface
Called as loopback

Network and Broadcast ID


IP address with all bits zero in the host part is the network ID.
For example 192.168.0.0 is network ID for /24 network.
IP address with all bits one in the host part is the broadcast ID for the network.
For example 192.168.0.255 is broadcast ID for /24 network.
Broadcast ID used for sending packets to all device under the network.

Conclusion


We are running out of address in IPv4
IPnG or Ipv6 is currently being implemented to solve this issue.
IPv4 is 32 bit whilst IPv6 is 128 bit.
IPv6 is supported on Linux, Mac OS and Windows.
IP allocated as CIDR.
Private IP cant be used in Internet.

Question

Download the ppt slides for IPv4 And Addressing presentation from here.