الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
GSM Cellular network has been under attack for long period. Now
two types of attacks are devised to attack it: active attack utilizing the fact
that it uses one-way authentication, so a rogue GSM network can deceive
a mobile device, convincing the device to connect to the fake network; and
passive attack utilizing the fact that a weak encryption algorithm called
A5/1 is used to encrypt calls, allowing an eavesdropper with an air tapping
device to do cryptanalysis cipher data reaching to the plain data.
Standards were developed to close these data breaches. Universal
SIM (USIM) integrate Authentication and Key Agreement module (AKA)
providing two-way authentication. Also stronger encryption algorithm
(A5/3) and even stronger encryption (A5/4) were standardized.
Another way for securely communicating is to tunnel a secure
connection inside a GSM CSD (Data) connection or an Internet
connection. This is referred to as a mobile crypto phone, and could be
implemented through hardware or software. A core challenge in
implementing it is the limitations in mobile platforms. For a software
implementation, limited processor speed and limited RAM Size, while
requiring a minimum processing delay are core limitations.
Ciphering is a core part of data confidentiality, it is an important
step to prevent data breaching in different modern mobile platforms. In
this work, AES was implemented efficiently in an Android application
written in Java. The Android application was tested for performance and
compared to other work. AES was also implemented in a Windows Phone
application written in C#, and a Windows console application written in
C++. In this work, AES implementation using 32-bit round lookup table
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was much faster than that using 8-bit separate transformation. AES
Encryption can be done efficiently on various platforms. Results were
compared to another software study implementing AES on Android
phones.
In this Thesis, Three Block Cipher modes of operation were
implemented in the C++ Console application. The first is Electronic Code
Book mode (ECB), this is the simplest mode and is only recommended to
encrypts small packets of data. The two other modes implemented in this
work , Cipher Block Chaining mode (CBC) and Counter mode (CTR)
mode. The main difference between the two is that the later allows precomputation;
this pre-computed value could be stored for later use , thus
diminishing the operations required in the real-time of encryption to only
an Exclusive-Or operation, allowing for a faster operation.
Key words:
Encryption, Android, Security, GSM, Advanced Encryption Standard,
A5/1, Software implementation, Windows Phone, Software Defined
Radio, Cryptographic Algorithms, AES, Encryption modes, Android
Security, Windows Phone Security, Rijndael, Java, C++, C#.