View source for Python-for-Automation/C2/File-Encryption-and-Decryption/English



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|-
|| '''Visual Cue'''
|| '''Narration'''
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|| Show slide: 

'''Welcome'''
|| Welcome to the Spoken Tutorial on '''"File Encryption and Decryption".'''
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|| Show slide: 


'''Learning Objectives'''
|| In this tutorial, we will learn to
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Encrypt a folder using Symmetric Encryption'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Generate a '''key'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Decrypt '''the '''folder '''using the '''key'''</div>

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|| Show Slide:

'''System Requirements'''
|| To record this tutorial, I am using
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Ubuntu''' '''Linux OS version 22.04'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Python 3.12.3'''</div>
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|| Show Slide:'''Prerequisites'''

[https://www.spoken-tutorial.org/ https://www.spoken-tutorial.org]
|| To follow this tutorial
* <div style="margin-left:1.27cm;margin-right:0cm;">You must have basic knowledge of using Linux Terminal and Python</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">For pre-requisite Linux and Python Tutorials, please visit this website</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Python libraries required for automation must be installed</div>

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'''Code Files'''
||
* <div style="margin-left:1.27cm;margin-right:0cm;">The files used in this tutorial are provided in the Code files link.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Please download and extract the files.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Make a copy and then use them while practicing.</div>

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|| Show Slide:'''Encryption and Decryption'''
|| '''Encryption '''secures data to prevent unauthorized access.

'''Decryption '''converts '''encrypted '''data back to its original form using a key.

This allows authorized users to access the information
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|| Show Slide:'''Symmetric Encryption'''
|| 
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Symmetric encryption technique '''uses the same key for both '''encryption '''and '''decryption'''.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">This makes it fast and efficient.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''AES '''('''Advanced''' '''Encryption Standard''') is a strong and popular method.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''AES '''supports 128, 192, and 256-bit keys for securing files and communications.</div>
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'''Encryption and Decryption - Libraries'''
|| To automate the '''encryption '''and '''decryption '''of a '''folder''', we need the below libraries:
* <div style="margin-left:1.27cm;margin-right:0cm;">'''os''' manages operating system interfaces like file operations and environment variables</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''cryptography '''offers secure communication and data integrity through algorithms</div>

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|| Show Slide:'''Securing Files with AES Encryption'''
|| In this '''tutorial''', we will see how to '''encrypt '''a folder named '''Sample '''and then '''decrypt '''it.

We will use the '''AES algorithm '''in '''Cipher Block Chaining<span style="color:#ff0000;"> </span>or CBC '''mode with a 128 bit key.
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|| Open the '''Downloads Folder'''
'''Files App > Downloads Folder > Sample'''

|| I have created a folder '''Sample '''which contains some files for demonstration.

Let us see how the '''Encryption and Decryption''' can be automated.
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|| Point to the '''encryption.py''' in downloads folder

Open the Text Editor with the source file
|| I have created the source file '''encryption.py''' for demonstration.

Now, we will go through the source code in the text editor. 
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|| Looking at the Code
|| This source code has '''encryption '''functionalities to provide security.
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|| Highlight:

'''import os'''

'''from cryptography.fernet import Fernet'''
|| First we need to import the '''libraries '''required to '''encrypt '''and '''decrypt '''folders.

The '''fernet class''' is used for '''symmetric encryption'''.
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'''def encrypt_file(file_path, key):'''
|| We define a function to '''encrypt '''each '''file '''by mentioning the path to it.
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'''with open(file_path, 'rb') as file:'''

'''file_data = file.read()'''
|| We then open the '''file '''in '''binary read mode rb''' and read its contents.

'''Binary read''' is used to read raw bytes from a file without any translation or conversion.
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'''fernet = Fernet(key)'''
|| A '''fernet '''instance is created using the provided '''key'''.
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'''encrypted_data = fernet.encrypt(file_data)'''
|| The data read from the file is '''encrypted '''using the '''fernet '''instance.
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'''encrypted_file_path = file_path + '.encrypted''''
|| We then add '''.encrypted''' to the original '''path '''to create a new '''file path'''.
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'''with open(encrypted_file_path, 'wb') as encrypted_file:'''

'''encrypted_file.write(encrypted_data)'''
|| Now, we open the '''file '''in '''binary write mode wb''' and write the '''encrypted '''data to it.

'''Binary Write''' is used to write raw bytes to a file without any translation or conversion.

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'''os.remove(file_path)'''
|| To prevent unauthorized access, only the '''encrypted '''version is retained.

The original files are removed using this command.
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|| This '''function '''stores all the '''encrypted '''files to the specified path. 
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'''encrypted_files = []'''
|| An empty list is initialized to store the paths of the '''encrypted '''files.
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|| We iterate through all '''directories '''and '''files '''mentioned in the path.

We then construct the full path, '''encrypt '''the files and add them to the list.
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'''def main(folder_path):'''
|| Finally, we define the main '''function '''to invoke the '''encryption '''process.
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'''key = Fernet.generate_key()'''
|| We generate a random '''symmetric encryption key '''using this function.
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'''print(f'Encryption Key: {key.decode()}')'''
|| The generated key is decoded and displayed.
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|| We call the '''function '''to '''encrypt '''all files in the specified path using the key.
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|| Highlight:''' '''
|| Now, we iterate over the '''encrypted '''files and print the path of each file.
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|| Finally, we set the '''path '''of the folder and call the '''main function '''with the path.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Save the Code in the '''Downloads '''Folder
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Save the code as '''encryption.py '''in the '''Downloads '''folder.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Open the terminal ('''Ctrl + Alt + T''')

Start Virtual Environment

Type

'''> source Automation/bin/activate'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Open the '''terminal''' by pressing '''Control + Alt + T '''keys simultaneously.

We will open the virtual environment we created for the '''Automation''' series.

Type '''source space Automation forward slash bin forward slash activate.'''

Then press enter.
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| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Running the Code

Type 

'''> <span style="background-color:#ffffff;">cd Downloads'''</span>

'''> python3 encryption.py'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | <span style="background-color:#ffffff;color:#252525;">Now type, </span><span style="background-color:#ffffff;color:#252525;">'''cd space Downloads'''</span><span style="background-color:#ffffff;color:#252525;">.</span>

<span style="color:#252525;">Then type</span><span style="color:#252525;">''' python3 </span><span style="background-color:#ffffff;color:#252525;">space </span>encryption<span style="color:#252525;">.py'''</span><span style="background-color:#ffffff;color:#252525;"> and press </span><span style="color:#252525;">'''Enter'''</span><span style="background-color:#ffffff;color:#252525;"> to run the code.</span>

<div style="color:#252525;">It executes the code and gives the output on the terminal as required.</div>

<span style="background-color:#ffffff;color:#252525;">The </span><span style="background-color:#ffffff;color:#252525;">'''key '''</span><span style="background-color:#ffffff;color:#252525;">displayed here is used while </span><span style="background-color:#ffffff;color:#252525;">'''decrypting '''</span><span style="background-color:#ffffff;color:#252525;">the files. So, let us copy it.</span>
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| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Navigating to Downloads

'''Files App > Downloads > Sample'''

'''Open doc3.txt'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Go back to the '''Downloads folder '''and double click to open the '''Sample '''folder.

The files and folders here are now '''encrypted''' as you can see because of the extension.

If we have any '''sub folders''', the files within them will be '''encrypted '''as well.

Let us open the encrypted file and check.

We can see the content of the file is encrypted and not in a readable format.

We need to decrypt the file to make it readable. Let us see how to do that.
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|| Point to the '''decryption.py''' in downloads folder

Open the Text Editor with the source file
|| I have created the source file '''decryption.py''' for demonstration.

Now, we will go through the source code in the text editor. 
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|| Highlight:
|| The same '''libraries '''we used to '''encrypt '''are used here as well.
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|| Highlight:
|| We define a function to '''decrypt '''each '''encrypted file '''by mentioning the path.
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|| Highlight:

'''fernet = Fernet(key)'''
|| A '''fernet '''instance is created using the provided '''key'''.
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|| Highlight:
|| We then open the '''encrypted file '''in '''binary read mode rb''' and read its contents.
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|| Highlight:
|| The '''encrypted '''data is now '''decrypted '''using the '''fernet '''object.
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|| 
|| Next, we define a path for the '''decrypted '''file after removing '''.encrypted''' from the file path.
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|| 
|| Now, we open a new '''file '''in '''binary write mode wb''' and write the '''decrypted '''data to it.
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|| 
|| Now, we delete the '''encrypted '''version of the file.
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|| 
|| The path of the '''decrypted '''file is displayed on the '''terminal'''.
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|| 
|| The next '''function '''we define''' '''is to store all the '''decrypted '''files.
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|| 
|| We '''iterate '''over the '''directory '''tree and construct the full path for each file.
The function to '''decrypt '''the files is called here.
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|| 
|| The path of the '''decrypted '''folder is displayed on the '''terminal'''.
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|| 
|| We set the path of the folder which contains the encrypted files.

Then, we paste the key which we copied earlier.
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|| 
|| Finally, we call the '''function '''which would '''decrypt '''the folder.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Save the Code in the '''Downloads '''Folder
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Save the code as '''decryption.py '''in the '''Downloads '''folder.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Observing the output on the terminal

'''type'''

'''>python3 decryption.py'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Switch back to the''' terminal'''.

<span style="background-color:#ffffff;color:#252525;">Now type, </span><span style="color:#252525;">'''python3 space </span>decryption<span style="color:#252525;">.py'''</span><span style="background-color:#ffffff;color:#252525;"> and press </span><span style="color:#252525;">'''Enter'''</span><span style="background-color:#ffffff;color:#252525;"> to run the code.</span>

<span style="background-color:#ffffff;color:#252525;">It executes the </span><span style="background-color:#ffffff;color:#252525;">'''script'''</span><span style="background-color:#ffffff;color:#252525;"> and displays the paths of all the </span><span style="background-color:#ffffff;color:#252525;">'''decrypted '''</span><span style="background-color:#ffffff;color:#252525;">files and the folder.</span>
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Navigating to Downloads

'''Files App > Downloads > Sample'''

'''Open a file by double clicking'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Go back to the '''Downloads folder '''and double click to open the '''Sample '''folder.

You can see the list of all the '''files '''we had originally not '''encrypted'''.

Now, you can double click to open the files.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Closing the virtual environment

Type 

'''> deactivate'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Switch back to the terminal to close the virtual environment.

Type '''deactivate'''.
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide:'''Summary'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | This brings us to the end of this tutorial. Let us summarise.

In this tutorial, we have learnt to
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Encrypt a folder using Symmetric Encryption'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Generate a '''key'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Decrypt '''the '''folder '''using the '''key'''</div>

|-
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'''Assignment'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | As an assignment, please do the following:

* <div style="margin-left:1.27cm;margin-right:0cm;">Modify the program '''decryption.py '''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Add exception handling to capture the missing encryption key</div>

|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide:'''About the Spoken Tutorial Project'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | The video at the following link summarises the '''Spoken Tutorial Project.'''Please download and watch it.
|-
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'''Spoken Tutorial Workshops'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | The '''Spoken Tutorial Project''' team conducts workshops and gives certificates.

For more details, please write to us.
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| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide:'''Answers for THIS Spoken Tutorial'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Please post your timed queries in this forum.
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| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide: 

'''FOSSEE Forum'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | For any general or technical questions on '''Python for Automation''', visit the '''FOSSEE forum''' and post your question.
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| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide:'''Acknowledgement'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | The '''Spoken Tutorial Project''' was established by the '''Ministry of Education, Government of India.'''
|-
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | Show Slide:'''Thank You'''
| style="border-top:1pt solid #000000;border-bottom:0.5pt solid #000000;border-left:0.5pt solid #000000;border-right:0.5pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.092cm;padding-right:0.191cm;" | This is '''Sai''' '''Sathwik''', a FOSSEE Semester Long Intern 2024, IIT Bombay signing off.

Thanks for joining.
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