\[ \begin{align}\begin{aligned}\newcommand\blank{~\underline{\hspace{1.2cm}}~}\\% Bold symbols (vectors) \newcommand\bs[1]{\mathbf{#1}}\\% Poor man's siunitx \newcommand\unit[1]{\mathrm{#1}} \newcommand\num[1]{#1} \newcommand\qty[2]{#1~\unit{#2}}\\\newcommand\per{/} \newcommand\squared{{}^2} \newcommand\cubed{{}^3} % % Scale \newcommand\milli{\unit{m}} \newcommand\centi{\unit{c}} \newcommand\kilo{\unit{k}} \newcommand\mega{\unit{M}} % % Percent \newcommand\percent{\unit{\%}} % % Angle \newcommand\radian{\unit{rad}} \newcommand\degree{\unit{{}^\circ}} % % Time \newcommand\second{\unit{s}} \newcommand\s{\second} \newcommand\minute{\unit{min}} \newcommand\hour{\unit{h}} % % Distance \newcommand\meter{\unit{m}} \newcommand\m{\meter} \newcommand\inch{\unit{in}} \newcommand\foot{\unit{ft}} % % Force \newcommand\newton{\unit{N}} \newcommand\kip{\unit{kip}} % kilopound in "freedom" units - edit made by Sri % % Mass \newcommand\gram{\unit{g}} \newcommand\g{\gram} \newcommand\kilogram{\unit{kg}} \newcommand\kg{\kilogram} \newcommand\grain{\unit{grain}} \newcommand\ounce{\unit{oz}} % % Temperature \newcommand\kelvin{\unit{K}} \newcommand\K{\kelvin} \newcommand\celsius{\unit{{}^\circ C}} \newcommand\C{\celsius} \newcommand\fahrenheit{\unit{{}^\circ F}} \newcommand\F{\fahrenheit} % % Area \newcommand\sqft{\unit{sq\,\foot}} % square foot % % Volume \newcommand\liter{\unit{L}} \newcommand\gallon{\unit{gal}} % % Frequency \newcommand\hertz{\unit{Hz}} \newcommand\rpm{\unit{rpm}} % % Voltage \newcommand\volt{\unit{V}} \newcommand\V{\volt} \newcommand\millivolt{\milli\volt} \newcommand\mV{\milli\volt} \newcommand\kilovolt{\kilo\volt} \newcommand\kV{\kilo\volt} % % Current \newcommand\ampere{\unit{A}} \newcommand\A{\ampere} \newcommand\milliampereA{\milli\ampere} \newcommand\mA{\milli\ampere} \newcommand\kiloampereA{\kilo\ampere} \newcommand\kA{\kilo\ampere} % % Resistance \newcommand\ohm{\Omega} \newcommand\milliohm{\milli\ohm} \newcommand\kiloohm{\kilo\ohm} % correct SI spelling \newcommand\kilohm{\kilo\ohm} % "American" spelling used in siunitx \newcommand\megaohm{\mega\ohm} % correct SI spelling \newcommand\megohm{\mega\ohm} % "American" spelling used in siunitx % % Inductance \newcommand\henry{\unit{H}} \newcommand\H{\henry} \newcommand\millihenry{\milli\henry} \newcommand\mH{\milli\henry} % % Power \newcommand\watt{\unit{W}} \newcommand\W{\watt} \newcommand\milliwatt{\milli\watt} \newcommand\mW{\milli\watt} \newcommand\kilowatt{\kilo\watt} \newcommand\kW{\kilo\watt} % % Energy \newcommand\joule{\unit{J}} \newcommand\J{\joule} % % Composite units % % Torque \newcommand\ozin{\unit{\ounce}\,\unit{in}} \newcommand\newtonmeter{\unit{\newton\,\meter}} % % Pressure \newcommand\psf{\unit{psf}} % pounds per square foot \newcommand\pcf{\unit{pcf}} % pounds per cubic foot \newcommand\pascal{\unit{Pa}} \newcommand\Pa{\pascal} \newcommand\ksi{\unit{ksi}} % kilopound per square inch \newcommand\bar{\unit{bar}} \end{aligned}\end{align} \]

Oct 24, 2024 | 545 words | 5 min read

11.1.1. Task 1

Learning Objectives

• Encrypt a plaintext into ciphertext.

• Encode the ciphertext into an image at a specified bit offset.

Task Instructions

Save the flowcharts for each of your tasks in tp3_team_teamnumber.pdf. You will also need to include these flowcharts in your final report.

Step 1: Encryption Functions

Similarly to the Vigenère cipher, you implemented in Section 10.2.2, create functions that use the XOR and Caesar cipher to encrypt a string. The functions should take two arguments: the plaintext message to be encrypted and the key. For the Caesar cipher, the key should be an integer representing the shift value. These functions should return the encrypted ciphertext message. You can find details on the XOR and Caesar ciphers in Section 10.1.1.

Note

Teams of 2 only need to implement the Vigenère cipher. Teams of 3 should implement the Vigenère cipher and one other cipher (either XOR or Caesar). Teams of 4 or more should implement all three ciphers.

Step 2: Encoding Function

Update the encoding function you wrote in Section 10.2.3 to embed the binary message into an image, so that it can insert the binary message at a specified bit offset. For example, if the offset is 5, the function should start encoding the message after the 5th bit of the image.

Step 3: Main Function

Create a main function that collects the following inputs from the user:

• a choice of encryption method (Caesar, XOR, or Vigenère)

• a plaintext message

• an encryption key

• the message start sequence

• the message end sequence

• the bit offset for encoding the message

• the path to an input image file

• the path to an output image file

• the path to a comparison image file

The function should encrypt the message using the chosen cipher, add the start and end sequences to the message, then convert the encrypted message to binary, and encode it into the image at the specified bit offset.

If the encoding is not successful, the main function should display an error message and stop. Otherwise, it should display a success message to the user and save and display the modified image.

Finally, building on the image comparison function you wrote in Section 10.2.1, the main function should compare the modified image with the comparison image, displaying the resulting image difference and printing whether the images are the same or different.

Use the files provided in the Table 11.13 to test your code.

Save your program as tp3_team_1_teamnumber.py.

Table 11.13 Image Files

Image File Name	Cipher	Key	Plaintext	Start Sequence	End Sequence	Bit Offset
ref_gry.png	None	None	None	None	None	None
ref_col.png	None	None	None	None	None	None
ref_gry_x.png	XOR	3RR0R	Sunny	12	21	13
ref_col_x.png	XOR	happy	ENGR 133	44	77	18
ref_gry_v.png	Vigenère	Up!	Boiler	22	88	2
ref_col_v.png	Vigenère	is fun	Math 101	31	&&	15
ref_gry_c.png	Caesar	159	Red Rose	5	1	11
ref_col_c.png	Caesar	777	Love ENGR	40	04	9

Sample Output

Use the values in Table 11.14 below to test your program.

Table 11.14 Test Cases

Case	cipher choice	plaintext	cipher key	start_seq	end_seq	bit offset	input image path	output image path	compare image path
1	xor	Sunny	3RR0R	12	21	13	ref_gry.png	gry_x.png	ref_gry_x.png
2	xor	ENGR 133	happy	44	77	18	ref_col.png	col_x.png	ref_col_x.png
3	vigenere	Boiler	Up!	22	88	2	ref_gry.png	gry_v.png	ref_gry_v.png
4	vigenere	Math 101	is fun	31	&&	15	ref_col.png	col_v.png	ref_col_v.png
5	caesar	Red Rose	159	5	1	11	ref_gry.png	gry_c.png	ref_gry_c.png
6	caesar	Love ENGR	777	40	04	9	ref_col.png	col_c.png	ref_col_c.png
7	caesar	Love ENGR	778	40	04	9	ref_col.png	col_c.png	ref_col_c.png
8	caesar	Love ENGR	777	40	04	25	ref_col.png	col_c.png	ref_col_c.png

Ensure your program’s output matches the provided samples exactly. This includes all characters, white space, and punctuation. In the samples, user input is highlighted like this for clarity, but your program should not highlight user input in this way.

Case 1 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: xor Enter the plaintext you want to encrypt: Sunny Enter the key for the cipher: 3RR0R Enter the start sequence: 12 Enter the end sequence: 21 Enter the bit offset before you want to start encoding: 13 Enter the path of the input image: ref_gry.png Enter the path for your encoded image: gry_x.png Enter the path of the image you want to compare: ref_gry_x.png Encrypted Message using XOR Cipher: `'<^+ Binary output message: 00110001 00110010 01100000 00100111 00111100 01011110 00101011 00110010 00110001 Message successfully encoded and saved to: gry_x.png The images are the same.

Fig. 11.1 Case_1_gry_x.png

Fig. 11.2 Case_1_plot_diff_image.png

Fig. 11.3 Case_1_plot_gry_x.png

Case 2 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: xor Enter the plaintext you want to encrypt: ENGR 133 Enter the key for the cipher: happy Enter the start sequence: 44 Enter the end sequence: 77 Enter the bit offset before you want to start encoding: 18 Enter the path of the input image: ref_col.png Enter the path for your encoded image: col_x.png Enter the path of the image you want to compare: ref_col_x.png Encrypted Message using XOR Cipher: -/7"YYRC Binary output message: 00110100 00110100 00101101 00101111 00110111 00100010 01011001 01011001 01010010 01000011 00110111 00110111 Message successfully encoded and saved to: col_x.png The images are the same.

Fig. 11.4 Case_2_col_x.png

Fig. 11.5 Case_2_plot_col_x.png

Fig. 11.6 Case_2_plot_diff_image.png

Case 3 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: vigenere Enter the plaintext you want to encrypt: Boiler Enter the key for the cipher: Up! Enter the start sequence: 22 Enter the end sequence: 88 Enter the bit offset before you want to start encoding: 2 Enter the path of the input image: ref_gry.png Enter the path for your encoded image: gry_v.png Enter the path of the image you want to compare: ref_gry_v.png Encrypted Message using Vigenère Cipher: Vdcftl Binary output message: 00110010 00110010 01010110 01100100 01100011 01100110 01110100 01101100 00111000 00111000 Message successfully encoded and saved to: gry_v.png The images are the same.

Fig. 11.7 Case_3_gry_v.png

Fig. 11.8 Case_3_plot_diff_image.png

Fig. 11.9 Case_3_plot_gry_v.png

Case 4 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: vigenere Enter the plaintext you want to encrypt: Math 101 Enter the key for the cipher: is fun Enter the start sequence: 31 Enter the end sequence: && Enter the bit offset before you want to start encoding: 15 Enter the path of the input image: ref_col.png Enter the path for your encoded image: col_v.png Enter the path of the image you want to compare: ref_col_v.png Encrypted Message using Vigenère Cipher: Usmm 489 Binary output message: 00110011 00110001 01010101 01110011 01101101 01101101 00100000 00110100 00111000 00111001 00100110 00100110 Message successfully encoded and saved to: col_v.png The images are the same.

Fig. 11.10 Case_4_col_v.png

Fig. 11.11 Case_4_plot_col_v.png

Fig. 11.12 Case_4_plot_diff_image.png

Case 5 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: caesar Enter the plaintext you want to encrypt: Red Rose Enter the key for the cipher: 159 Enter the start sequence: 5 Enter the end sequence: 1 Enter the bit offset before you want to start encoding: 11 Enter the path of the input image: ref_gry.png Enter the path for your encoded image: gry_c.png Enter the path of the image you want to compare: ref_gry_c.png Encrypted Message using Caesar Cipher: Uhg Urvh Binary output message: 00110101 01010101 01101000 01100111 00100000 01010101 01110010 01110110 01101000 00110001 Message successfully encoded and saved to: gry_c.png The images are the same.

Fig. 11.13 Case_5_gry_c.png

Fig. 11.14 Case_5_plot_diff_image.png

Fig. 11.15 Case_5_plot_gry_c.png

Case 6 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: caesar Enter the plaintext you want to encrypt: Love ENGR Enter the key for the cipher: 777 Enter the start sequence: 40 Enter the end sequence: 04 Enter the bit offset before you want to start encoding: 9 Enter the path of the input image: ref_col.png Enter the path for your encoded image: col_c.png Enter the path of the image you want to compare: ref_col_c.png Encrypted Message using Caesar Cipher: Ilsb BKDO Binary output message: 00110100 00110000 01001001 01101100 01110011 01100010 00100000 01000010 01001011 01000100 01001111 00110000 00110100 Message successfully encoded and saved to: col_c.png The images are the same.

Fig. 11.16 Case_6_col_c.png

Fig. 11.17 Case_6_plot_col_c.png

Fig. 11.18 Case_6_plot_diff_image.png

Case 7 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: caesar Enter the plaintext you want to encrypt: Love ENGR Enter the key for the cipher: 778 Enter the start sequence: 40 Enter the end sequence: 04 Enter the bit offset before you want to start encoding: 9 Enter the path of the input image: ref_col.png Enter the path for your encoded image: col_c.png Enter the path of the image you want to compare: ref_col_c.png Encrypted Message using Caesar Cipher: Jmtc CLEP Binary output message: 00110100 00110000 01001010 01101101 01110100 01100011 00100000 01000011 01001100 01000101 01010000 00110000 00110100 Message successfully encoded and saved to: col_c.png The images are different.

Fig. 11.19 Case_7_col_c.png

Fig. 11.20 Case_7_plot_col_c.png

Fig. 11.21 Case_7_plot_diff_image.png

Case 8 Sample Output

$ python3 tp3_team_1_teamnumber.py Enter the cipher you want to use for encryption: caesar Enter the plaintext you want to encrypt: Love ENGR Enter the key for the cipher: 777 Enter the start sequence: 40 Enter the end sequence: 04 Enter the bit offset before you want to start encoding: 25 Enter the path of the input image: ref_col.png Enter the path for your encoded image: col_c.png Enter the path of the image you want to compare: ref_col_c.png Given message is too long to be encoded in the image. Encrypted Message using Caesar Cipher: Ilsb BKDO Binary output message: 00110100 00110000 01001001 01101100 01110011 01100010 00100000 01000010 01001011 01000100 01001111 00110000 00110100