This is a substitution cypherEach letter is replaced by another letter with no repetitionIgnore spaces and punctuationYou must account for spaces (I ignored them, but there are other legitimate responses.)The best program will also account for punctuation and other symbols. (Ignoring them is fine.) Your program can ignore these special characters when they occur, but it should not crash if it encounters a strange character.Manage CapitalizationIn most cryptographic applications, all letters are converted to uppercase. Please follow this convention or deal with potential case conversion problems in another way.Use FunctionsYou may not make significant changes to the main function. Determine which functions are necessary and create them. (The blackbelt project does allow for one slight modification, noted below.) Do not turn in a program with only a main() function!! Write the code necessary for Python to run the main function as expectedPass data between functionsYour functions may require some input and return some output. Part of the task is to determine how the methods are to be created.Using a keyThere's several workable answers, but I used a string with all the alphabet characters and a second string with a "scrambled" version of the alphabet.Useful String methodsThis program is all about string manipulation, so you may want to use help("str") in your python shell to look up some useful techniques. Here are a few things you might need to know how to do:determine the length of a stringconvert a string to upper casefind the position of a character in a stringDetermine the character at a certain position in a string Create a program that assists in a basic form of cryptography, a substitution cypher. Write a program that will accept a phrase and convert it into code by substitutingletters according to a key.This program will also be an example of functions. You will be given a main function body. This function refers to a number of other functions which you will have tocreate. It's part of your job to figure out how these functions should be created and what their parameters and output should be.The program is based on a standard text-based menu. You'Ill need to create methods (function) to display the menu, get input from it, and handle the details. Yourprogram should encrypt and decrypt messages.Sample RunHere's a sample run of the basic program in action.SECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 1text to be encoded: Python Rocks!AQULEWKEMNJSECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 2code to be decyphered: AQULEWKEMNJΡΥTHONROCKSSECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 0Thanks for doing secret spy stuff with me. Starter CodeYou may copy and paste the following code into your editor to get started. You may also type the code by hand, but your main method must be identical to the oneposted here:crypto.pyImplements a simple substitution cypherII IIII(alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"key"XPMGTDHLYONZBWEARKJUFSCIQV".def main():keepGoing = Truewhile keepGoing:response = menu()if response =="1":plain = input("text to be encoded: ")print(encode(plain))elif response == "2":coded = input("code to be decyphered: ")print (decode(coded))elif response == "0":print ("Thanks for doing secret spy stuff with me.")keepGoing = Falseelse:print ("I don't know what you want to do...")#my starter code.if name_ ==__main__":main()

Question

This is a substitution cypherEach letter is replaced by another letter with no repetitionIgnore spaces and punctuationYou must account for spaces (I ignored them, but there are other legitimate responses.)The best program will also account for punctuation and other symbols. (Ignoring them is fine.) Your program can ignore these special characters when they occur, but it should not crash if it encounters a strange character.Manage CapitalizationIn most cryptographic applications, all letters are converted to uppercase. Please follow this convention or deal with potential case conversion problems in another way.Use FunctionsYou may not make significant changes to the main function. Determine which functions are necessary and create them. (The blackbelt project does allow for one slight modification, noted below.) Do not turn in a program with only a main() function!! Write the code necessary for Python to run the main function as expectedPass data between functionsYour functions may require some input and return some output. Part of the task is to determine how the methods are to be created.Using a keyThere's several workable answers, but I used a string with all the alphabet characters and a second string with a &#34;scrambled&#34; version of the alphabet.Useful String methodsThis program is all about string manipulation, so you may want to use help(&#34;str&#34;) in your python shell to look up some useful techniques. Here are a few things you might need to know how to do:determine the length of a stringconvert a string to upper casefind the position of a character in a stringDetermine the character at a certain position in a string Create a program that assists in a basic form of cryptography, a substitution cypher. Write a program that will accept a phrase and convert it into code by substitutingletters according to a key.This program will also be an example of functions. You will be given a main function body. This function refers to a number of other functions which you will have tocreate. It's part of your job to figure out how these functions should be created and what their parameters and output should be.The program is based on a standard text-based menu. You'Ill need to create methods (function) to display the menu, get input from it, and handle the details. Yourprogram should encrypt and decrypt messages.Sample RunHere's a sample run of the basic program in action.SECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 1text to be encoded: Python Rocks!AQULEWKEMNJSECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 2code to be decyphered: AQULEWKEMNJΡΥTHONROCKSSECRET DECODER MENU0) Quit1) Encode2) DecodeWhat is your choice: 0Thanks for doing secret spy stuff with me. Starter CodeYou may copy and paste the following code into your editor to get started. You may also type the code by hand, but your main method must be identical to the oneposted here:crypto.pyImplements a simple substitution cypherII IIII(alpha = &#34;ABCDEFGHIJKLMNOPQRSTUVWXYZ&#34;key&#34;XPMGTDHLYONZBWEARKJUFSCIQV&#34;.def main():keepGoing = Truewhile keepGoing:response = menu()if response ==&#34;1&#34;:plain = input(&#34;text to be encoded: &#34;)print(encode(plain))elif response == &#34;2&#34;:coded = input(&#34;code to be decyphered: &#34;)print (decode(coded))elif response == &#34;0&#34;:print (&#34;Thanks for doing secret spy stuff with me.&#34;)keepGoing = Falseelse:print (&#34;I don't know what you want to do...&#34;)#my starter code.if name_ ==__main__&#34;:main()

Accepted Answer

import string
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
key = "XPMGTDHLYONZBWEARKJUFSCIQV"
def…