Preparation of Papers in Two-Column Format

For Conference Proceedings Sponsored by IEEE

J.Q. Author

IEEE Conference Publishing

445 Hoes LanePiscataway, NJ 08854 USA

Abstract-

I. INTRODUCTION

Main Cryptography science is the study of hiding and verification information. It is often referred to as “the study of secret” when data exchanged over the internet, networks or other media. It’s the Art of protecting data and Information from unauthorized access by transforming it into a non-readable format, called ciphertext.

Only those who have a secret key can decrypt or decipher the encrypted message into plain text. It includes the algorithms, protocols, and methodologies to secure and prevent or delay unapproved access to sensitive information and enable verifiability of every component in a communication. A cryptographic algorithm, which is also called a cipher, is the mathematical function or equation used for encryption and decryption.

Generally, encryption and decryption are two related functions for the cryptographic system. decryption/encryption protects data and information from being attacked by the attacker. decryption/encryption is a security system where cipher or encryption algorithms are carried out together with a secret key to encrypt/decrypt data so that they are unreadable in the event that they are intercepted.

With the fast improvement of Internet and communication technologies, image communication plays a very important role in transmitting information, what’s more, the image encryption/decryption has attracted more and more attention. (Due to the fast growth of the internet in the digital world today, the security of digital images has become more important and been given more attention.) Digital images have essential properties that are different from texts, such as strong correlation among pixels and bulk data capacity, which make some traditional encryption methods are not very suitable for digital image encryption 1,2.

Encryption methods of digital images are very important and should be used to frustrate antagonist attacks from unauthorized access.

As the number of Internet users has grown exponentially around the world, the need to protect data, information, and multimedia on the Internet has become a high priority. Most operations in governments, military installations, financial institutions, hospitals and private companies deal heavily with data that is in the form of an image or multiple media, most encryption algorithms today are based on text-only data.

In this paper a modified cryptographic algorithm system based on binary codes (0,1) bits by using a mathematical equation. The main idea of this algorithm is converting 0-bit value to 1-bit value and 1-bit value to 0-bit value by using a mathematical equation depends on the bit values of secret key and target message by using logic functions. The target message is divided into bytes each of which is composed of 8 bits. The secret key length is modified to be equal to the target message length. Changing the value of the bits depends on a truth table which the secret key and target message act as main elements in it. The decryption procedure is similar in process to the encryption in the same order. The proposed algorithm system can regenerate the original binary data byte with no loss of data or information for the encryption and decryption process. By using unlimited secret keys length, the algorithm is more secure and it’s hard to guess the key value or attacked. The proposed algorithm has been compared with other recent algorithm and it was fast, simple and flexible enough. Validation of our new algorithm the security requirements have been applied and it has been suitable for using it in many software and hardware applications.

The second section Related Work, demonstrate the problem formulation, the proposed algorithm (CryptoBin) will be explained in the third section, the fourth section discusses the Architecture of the Algorithm System, the implementation of the system in the fifth section, the sixth section proves the strength, the Performance and Security Analysis for cryptographic system and its results, and finally the conclusion will be introduced.

2. Related Work

Security issues are ubiquitous. Both senders as well

as receiver faces the security issues. This section describes

the existing work.

Recently, a new cryptographic algorithm system for binary codes based on a proposed mathematical equation was created and approved by Statistical Tests for Cryptographic Applications and the Results were good and acceptable compared to other cryptographic algorithms. The main idea of that algorithm is converting zero to one and one to zero by using a mathematical equation uses the values, which generated from the inserted two keys by mathematical function using based on logic functions. The message is divided into bytes each of which is composed of 8 bits. The first key specifies the bit where the change of bit value (0 to 1, 1 to 0) occurs till the end of each byte of the message. The second key value is used to calculate how many bytes used with the first key value before it decreased by one-bit value. The decryption procedure is similar in process to the encryption in the same order. The proposed algorithm system can regenerate the original binary data byte with no loss of data or information for the encryption and decryption process. By using two secret keys, the algorithm is more secure and it’s hard to guess the keys value or attacked.

3 Proposed Work

The cryptographic algorithm system for binary codes which discussed and published after many tests and trials to attack it found that it has some drawbacks and weakness in the secret key system.

The security of communication network has been widely studied by researchers. This article will perform a comparative study between DES, 3DES, AES and CryptoBin algorithm (ours). So that A new method for secure communication of information and multimedia encryption proposed here. This method includes advantages of both multimedia (Audio, Image, and video) cryptography and normal encryption data. This article is used to achieve and solve the problem of the weakness and drawbacks of the former system that mentioned before and it strengthens the secret key to be unbreakable.

This cryptographic algorithm system is called CryptoBin which deals with Binary codes (0&1) bits. The proposed secret key is a binary number which characterized by an unlimited size of bits, the bits can be less, equal or greater than the target message (plain text). The algorithm system compares the bit value of the secret key with the bit value of the target message and generates a new encrypted message that has an equal length of the target message. The algorithm system compares the bit value of the secret key and the target message using logical equations based on a truth table, resulting in the encrypted message. For example, if the bit value of the secret key is equal to “1”, the bit value of the target message will change from “1” to “0” or “0” to “1”, else if the bit value of the secret key is “0”, the bit value of the target message will be left as it “0” is “0” and “1” is “1” unchanged.

4. Architecture of The Algorithm System

The CryptoBin algorithm consists of the secret key which is a binary number known by the two parties, the target message which will be sent from the sender to the receiver, and a truth table which controls the output bit’s value (encrypted bit).

A) encryption system

For example;

plain text = “Hello World”

binary input = “0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100”

secret key = “723”in decimal form

Secret key = “1011010011”in binary form

To obtain a modified secret key to be equal in bit’s length to the target message it should be repeated.

Modified secret key = “1011010011101101001110110100111011010011101101001110110100111011010011101101001110110100”

Truth Table =

66929047625 Unchanged Values

Key

0

0

1

1

0

MsgEnc Msg0

1

1

0

1

0

1

Changed Values

00 Unchanged Values

Key

0

0

1

1

0

MsgEnc Msg0

1

1

0

1

0

1

Changed Values

The common idea of Truth Table that if the key’s bit value is “0” then the encrypted bit value will be unchanged, else if the key’s bit value is “1” then the encrypted bit value will be changed from “1” to “0” or “0” to “1”.

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1

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0

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0

1

0

0

1

0

0

0

1

1

1

1

1

0

1

0

(c)

First 8-bits

of the Encrypted Message

(b)

First 8-bits

of the Target Message

(a)

First 8-bits

of the Secret key

yes

no

yes

yes

no

no

yes

no

Bit Changed

00+

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1

0

1

1

0

0

1

0

0

1

0

0

1

0

0

0

1

1

1

1

1

0

1

0

(c)

First 8-bits

of the Encrypted Message

(b)

First 8-bits

of the Target Message

(a)

First 8-bits

of the Secret key

yes

no

yes

yes

no

no

yes

no

Bit Changed

Plain message

Bit no. 1 2 3 4 5 6 7 8 9 10 11 12 0 1 0 0 1 0 0 0 0 1 1 0 13 0 1 0 1 0 1 1 0 1 1 0 0 24

25 0 1 1 0 1 1 0 0 0 1 1 0 36

37 1 1 1 1 0 0 1 0 0 0 0 0 48

49 0 1 0 1 0 1 1 1 0 1 1 0 60

61 1 1 1 1 0 1 1 1 0 0 1 0 72

73 0 1 1 0 1 1 0 0 0 1 1 0 84

85 0 1 0 0 88 Key

Bit no. 1 2 3 4 5 6 7 8 9 10 1 2 1 0 1 1 0 1 0 0 1 1 1 0 3 1 1 0 1 0 0 1 1 1 0 1 1 4

5 0 1 0 0 1 1 1 0 1 1 0 1 6

7 0 0 1 1 1 0 1 1 0 1 0 0 8

9 1 1 1 0 1 1 0 1 0 0 1 1 10

1 1 0 1 1 0 1 0 0 1 1 1 0 2

3 1 1 0 1 0 0 1 1 1 0 1 1 4

5 0 1 0 0 8 Encrypted Message

Bit no. 1 2 3 4 5 6 7 8 9 10 11 12 1 1 1 1 1 1 0 0 1 0 0 0 13 1 0 0 0 0 1 0 1 0 1 1 1 24

25 0 0 1 0 0 0 1 0 1 0 1 1 36

37 1 1 0 0 1 0 0 1 0 1 0 0 48

49 1 0 1 1 1 0 1 0 0 1 0 1 60

61 0 1 0 0 0 0 1 1 1 1 0 0 72

73 1 0 1 1 1 1 1 1 1 1 0 1 84

85 0 0 0 0 88 Encrypted Binary = “1111110010001000010101110010001010111100100101001011101001010100001111001011111111010000”

Encrypted text = “üˆW”¼”ºT<¿Ð”

B) decryption system

For Decrypting the same example;

Encrypted text = “üˆW”¼”ºT<¿Ð”

Encrypted Binary = “1111110010001000010101110010001010111100100101001011101001010100001111001011111111010000”

secret key = “723”in decimal form

Secret key = “1011010011”in binary form

To obtain a modified secret key to be equal in bit’s length to the target message it should be repeated.

Modified secret key = “1011010011101101001110110100111011010011101101001110110100111011010011101101001110110100”

Truth Table =

Unchanged Values

Key

0

0

1

1

0

Enc MsgDec Msg0

1

1

0

1

0

1

Changed Values

Unchanged Values

Key

0

0

1

1

0

Enc MsgDec Msg0

1

1

0

1

0

1

Changed Values

+

+

+

+

+

+

+

+

1

0

1

1

0

0

1

0

1

1

1

1

1

0

1

0

0

1

0

0

1

0

0

0

(c)

First 8-bits

of the Decrypted Message

(b)

First 8-bits

of the Encrypted Message

(a)

First 8-bits

of the Secret key

yes

no

yes

yes

no

no

yes

no

Bit Changed

+

+

+

+

+

+

+

+

1

0

1

1

0

0

1

0

1

1

1

1

1

0

1

0

0

1

0

0

1

0

0

0

(c)

First 8-bits

of the Decrypted Message

(b)

First 8-bits

of the Encrypted Message

(a)

First 8-bits

of the Secret key

yes

no

yes

yes

no

no

yes

no

Bit Changed

Encrypted Message

Bit no. 1 2 3 4 5 6 7 8 9 10 11 12 1 1 1 1 1 1 0 0 1 0 0 0 13 1 0 0 0 0 1 0 1 0 1 1 1 24

25 0 0 1 0 0 0 1 0 1 0 1 1 36

37 1 1 0 0 1 0 0 1 0 1 0 0 48

49 1 0 1 1 1 0 1 0 0 1 0 1 60

61 0 1 0 0 0 0 1 1 1 1 0 0 72

73 1 0 1 1 1 1 1 1 1 1 0 1 84

85 0 0 0 0 88 Key

Bit no. 1 2 3 4 5 6 7 8 9 10 1 2 1 0 1 1 0 1 0 0 1 1 1 0 3 1 1 0 1 0 0 1 1 1 0 1 1 4

5 0 1 0 0 1 1 1 0 1 1 0 1 6

7 0 0 1 1 1 0 1 1 0 1 0 0 8

9 1 1 1 0 1 1 0 1 0 0 1 1 10

1 1 0 1 1 0 1 0 0 1 1 1 0 2

3 1 1 0 1 0 0 1 1 1 0 1 1 4

5 0 1 0 0 8 Decrypted message

Bit no. 1 2 3 4 5 6 7 8 9 10 11 12 0 1 0 0 1 0 0 0 0 1 1 0 13 0 1 0 1 0 1 1 0 1 1 0 0 24

25 0 1 1 0 1 1 0 0 0 1 1 0 36

37 1 1 1 1 0 0 1 0 0 0 0 0 48

49 0 1 0 1 0 1 1 1 0 1 1 0 60

61 1 1 1 1 0 1 1 1 0 0 1 0 72

73 0 1 1 0 1 1 0 0 0 1 1 0 84

85 0 1 0 0 88 Decrypted binary output = “0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100”

Decrypted text = “Hello World”

5. CryptoBin IMPLEMENTATION

Now we propose the Cryptobin algorithm encryption by using simple coding language such as VB.NET. For simplicity, we use a simple series of binary codes for plaintext and secret key.

111379062230Key m-bits

00Key m-bits

97155081915Modified key n-bits

00Modified key n-bits

2042160168910O n-bits

00O n-bits

332105168910I n-bits

00I n-bits

3898905397500

‘Encryption Process

‘plain text = “Hello World”

Dim input_str = “0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100”

Dim key = “1011010011” ‘723 in decimal form

Dim key_bit = “”

Dim txt_bit = “”

Dim res_bit = “”

Dim result = “”

Dim key_lengthFor x = 0 To input_str.Length – 1 Step key.Length key_length = key.Length’if no. of bits of plaintext length ; no. of bits of key length

If (input_str.Length) – x ; key.Length Then key_length = (input_str.Length) – x

For n = 1 To key_length txt_bit = Mid(input_str, x + n, 1)

key_bit = Mid(key, n, 1)

If key_bit = “0” And txt_bit = “0” Then

res_bit = “0”

ElseIf key_bit = “0” And txt_bit = “1” Then

res_bit = “1”

ElseIf key_bit = “1” And txt_bit = “0” Then

res_bit = “1”

ElseIf key_bit = “1” And txt_bit = “1” Then

res_bit = “0”

End If

result = result + res_bit Next n

Next x

result = “1111110010001000010101110010001010111100100101001011101001010100001111001011111111010000” ‘Encrypted

‘————————————————————————

‘Decryption Process

‘Encrypted text = “1111110010001000010101110010001010111100100101001011101001010100001111001011111111010000”

Dim input_str = “1111110010001000010101110010001010111100100101001011101001010100001111001011111111010000”

Dim key = “1011010011” ‘723 in decimal form

Dim key_bit = “”

Dim txt_bit = “”

Dim res_bit = “”

Dim result = “”

Dim key_lengthFor x = 0 To input_str.Length – 1 Step key.Length key_length = key.Length’if no. of bits of plaintext length ; no. of bits of key length

If (input_str.Length) – x ; key.Length Then key_length = (input_str.Length) – x

For n = 1 To key_length txt_bit = Mid(input_str, x + n, 1)

key_bit = Mid(key, n, 1)

If key_bit = “0” And txt_bit = “0” Then

res_bit = “0”

ElseIf key_bit = “0” And txt_bit = “1” Then

res_bit = “1”

ElseIf key_bit = “1” And txt_bit = “0” Then

res_bit = “1”

ElseIf key_bit = “1” And txt_bit = “1” Then

res_bit = “0”

End If

result = result + res_bit Next n

Next x

result = “0100100001100101011011000110110001101111001000000101011101101111011100100110110001100100” ‘Decrypted

we can use this code for encrypting images also. For example, we use image file “m.png” and the encrypted file named “m-Encrypt.png”, figure () shows the image before and after encryption or decryption

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3 Performance and Security Analysis

A good encryption scheme and image cipher should resist all kinds of known attacks, such as the man in middle attack, cipher-text attack, dictionary attack, side channel attack, differential attack, and various brute-force attacks. Some security analysis techniques perform on the CryptoBin encryption scheme, including the statistical, analysis and key space analysis.

In this section, we discuss the security analysis of the proposed CryptoBin encryption for image encryption, such as Histogram Analysis, Correlation between Plain and Cipher Images, Information Entropy, and Key Space Analysis to prove that the proposed image cipher is effective and secure against the most common attacks. Experiments are carried out using the Matlab software.

The key parameter is key)Decimal = 723 or key)Binary = 1011010011 This parameter must be kept secret. The same key is used to decrypt the cipher-images.

3.1 Statistical Analysis

To demonstrate the strength of the proposed encryption system, a statistical analysis was performed showing superior confusion and diffusion characteristics in the nature of strong resistance against statistical attacks This is done by the study of Histogram Analysis, Correlation between Plain and Cipher Images, Information Entropy, and Key Space Analysis between the original and ciphered images.

Statistical analysis has been performed on the CryptoBin, demonstrating its superior confusion and diffusion properties which strongly defend against statistical attacks. This is shown by a test on the histograms of the enciphered image and on the correlation of adjacent pixels in the ciphered image.

3.1.1 Histogram Analysis

Shannon pointed that there are two methods of diffusion and

confusion in order to defeat the powerful attacks based on statistical analysis 18. Histogram test is one of Shannon methods and it is applied to ciphered images. We have a grey-scale image (256×256) has different contents, and we calculate its histogram which shows the distribution of pixel intensities of the image. the attacker uses frequency analysis to obtain the secret key or the plain-pixels. This attack type is called a statistical attack. To prevent that statistical attack, the histogram of original image and histogram of the encrypted image shouldn’t have a statistical similarity. Therefore, the histogram of encrypted image should be relatively flat or with a uniform statistical distribution, indicating the strength and quality of the encryption system 6.

Figure () (a) and (b) show histograms of image ‘m.png’ before and after encryption. Histogram of the encrypted image looks relatively flat and with a uniform statistical distribution and different from the histogram of the original image. Based on the experiment results above, we find that encryption process returns noisy image, histograms of encrypted image are very close to uniform distribution, significantly different from that of the original image and contain no statistical similarity to the original image flat histogram in Encrypted images can make an attacker’s task very difficult to infer pixel values or secret keys using a statistical attack. This corresponds to the ideal security set by Shannon 27, and the encryption system resists against known attack.

Histogram of original image

Histogram of original image

Original image

Original image

Encrypted image

Encrypted image

Histogram of Encrypted image

Histogram of Encrypted image

Fig. 3 Histograms of the plain image and ciphered image

Fig. 3 Histograms of the plain image and ciphered image

3.1.2 Correlation between Plain and Cipher Images

Correlation is some of a wide class of statistical relationships involving dependence, though in keeping usage it usually identifies how close two variables are to presenting a linear relationship together. We’ve also analyzed the correlation between two vertically, horizontally, and diagonally adjacent pixels in several plain images and their corresponding encrypted images. The correlation coefficient analysis indicates the partnership among pixels in the cipher image.

In the newest scheme, the correlation among adjacent pixels is less than that of the original image. This low correlation value between the original images and their encryption indicates less resemblance between them, which supplies more resistance to attacks. The Statistical correlation is a measure that states the effectiveness of linear relationship between two random variables.

Let x and y are two random variables, each consisting of n elements, the correlation coefficient of both random variables is calculated by the equation:

rxy= covx.yDxDyDx=1ni=1nxi-Ex2covx.y=1ni=1nxi-Exyi-EyEx=1nnxiOriginal image (Fig 3a) Encrypted image (Fig 3e)

Horizontal 0.9427 0.0082

Vertical 0.9858 -0.0005

Diagonal 0.9358 -0.4020

We observe from correlation charts and Table 4 that there’s a negligible correlation between both adjacent pixels in the ciphered image. However, both adjacent pixels in the original image are strongly correlated. Correlation in the encrypted images is exceptionally little or insignificant when the proposed encryption scheme is utilized. Hence the proposed scheme has great change and substitution properties.

3.1.3 Information EntropyThe information entropy is the mathematical theory of data communication and storage founded in 1949 by Shannon 12. information entropy is an important indicator of randomness and can be calculated by Eq. (14)

Hm=-i=02N-1Pmilog2Pmiwhere P(mi) is the emergence probability of mi. If every symbol has an equal probability, i.e., m={m0,m1,m2,…m28 -1} and P(mi)=1/28(i=0,1,…255), then the entropy is H(m)=8 which corresponds to an ideal case. Practically, the information entropies of encrypted images are less compared to the ideal case. To design a good image encryption scheme, the entropy of encrypted image close to the ideal case is expected. The closer the information entropy is to 8, we can say the image is more random in some way. The entropies of some plaintext images and their corresponding cipher images are shown in Table2.

Image Entropy value

Original Image(plain Image) 7.1200

Encrypted Image (Cipher Image) 7.9919

3.2 Key space Analysis

A good encryption scheme should be sensitive to the secret

keys, and the key space should be large enough to make brute force attacks infeasible. In our case, the key space size is unlimited. It can be large enough to resist at all type of brute force attacks. The experimental results also demonstrate that

CryptoBin is very sensitive to the secret key. Table () illustrates the sensitivity of CryptoBin to the secret key ki. As can be seen when the secret key ki is changed slightly the correlation coefficients becomes absolutely different. as shown in Table II.

Correlation Horizontal Vertical

Plain Image 0.9427 0.9858

Encrypted Image by K1 -0.0174 0.0160

Encrypted Image by K1 0.0711 0.0785

Encrypted Image by K1 0.0078 0.0068

The important difference between image encryption and text encryption is the image size which is almost always much greater than the text size. For that, the use of traditional cryptosystems needs much time to encrypt the image. The other difference is related to decryption, the decrypted image allowed to some changing from the original image while this case not allowed in text decryption 5

A new algorithm is presented, which concatenates two or more images of different types and

sizes and performs lossless mixing and encryption in three steps. These steps include a shuffling

step and a substitution step, combining stream cipher with the block cipher. The algorithm was

implemented and tested. Analysis showed the effectiveness of the cipher and its resistance to attacks.

CONCLUSION and future work