def play():
"""
Asks the user what cipher he wants to use,
in order to encrypt or decrypt a text message.
Gives user the option to return the cipher text in 5 characters blocks.
Asks user for different input based on cipher selection.
Adds a onetime pad as an additional security layer.
If encrypting:
Returns cipher text encrypted with the chosen cipher and onetime pad.
If decrypting:
Returns text decrypted with the chosen cipher and onetime pad.
"""
working = True
cipher_choice = True
enc_dec = True
letters = string.ascii_uppercase
while working:
clear_screen()
print(
"This is the Secret Messages project for the Treehouse Techdegree. \n"
"These are the current available ciphers: \n"
"- Affine \n"
"- Atbash \n"
"- Caesar \n"
"- Keyword \n"
"- Type (Q) to quit. \n")
while cipher_choice:
choice = input(
"Type the name of the cipher would you like to use? \n")
if choice.upper() == 'Q':
exit()
elif choice.upper() == 'AFFINE':
cipher = Affine()
break
elif choice.upper() == 'ATBASH':
cipher = Atbash()
break
elif choice.upper() == 'CAESAR':
cipher = Caesar()
break
elif choice.upper() == 'KEYWORD':
cipher = Keyword()
break
else:
print('Type the name of any available cipher. \n')
user_text = input('What is your message?(Letters only) \n')
while enc_dec:
e_or_d = input('Are we going to encrypt or decrypt? \n')
if e_or_d.upper() == 'ENCRYPT' and isinstance(cipher, Affine):
alpha, beta = get_keys()
ot_pad = input('Type your one time pad. \n')
ot_val = cipher.one_time_pad(user_text, ot_pad)
value = cipher.encrypt(ot_val, alpha, beta)
block_choice = yes_or_no()
if block_choice.upper() == 'Y':
value = cipher.add_padding(value)
print(value + '\n')
repeat()
break
else:
print(value + '\n')
repeat()
break
elif e_or_d.upper() == 'DECRYPT' and isinstance(cipher, Affine):
alpha, beta = get_keys()
ot_pad = input(
'Type your one time pad, must be the same used for encrypting. \n'
)
block_choice = y_o_n()
if block_choice.upper() == 'Y':
no_block = cipher.remove_padding(user_text)
value = cipher.decrypt(no_block, alpha, beta)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
else:
value = cipher.decrypt(user_text, alpha, beta)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
elif e_or_d.upper() == 'ENCRYPT' and isinstance(cipher, Atbash):
ot_pad = input('Type your one time pad. \n')
ot_val = cipher.one_time_pad(user_text, ot_pad)
value = cipher.encrypt(ot_val)
block_choice = yes_or_no()
if block_choice.upper() == 'Y':
value = cipher.add_padding(value)
print(value + '\n')
repeat()
break
else:
print(value + '\n')
repeat()
break
elif e_or_d.upper() == 'DECRYPT' and isinstance(cipher, Atbash):
ot_pad = input(
'Type your one time pad, must be the same used for encrypting. \n'
)
block_choice = y_o_n()
if block_choice.upper() == 'Y':
no_block = cipher.remove_padding(user_text)
value = cipher.decrypt(no_block)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
else:
value = cipher.decrypt(user_text)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
elif e_or_d.upper() == 'ENCRYPT' and isinstance(cipher, Caesar):
ot_pad = input('Type your one time pad. \n')
ot_val = cipher.one_time_pad(user_text, ot_pad)
value = cipher.encrypt(ot_val)
block_choice = yes_or_no()
if block_choice.upper() == 'Y':
value = cipher.add_padding(value)
print(value + '\n')
repeat()
break
else:
print(value + '\n')
repeat()
break
elif e_or_d.upper() == 'DECRYPT' and isinstance(cipher, Caesar):
ot_pad = input(
'Type your one time pad, must be the same used for encrypting. \n'
)
block_choice = y_o_n()
if block_choice.upper() == 'Y':
no_block = cipher.remove_padding(user_text)
value = cipher.decrypt(no_block)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
else:
value = cipher.decrypt(user_text)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
elif e_or_d.upper() == 'ENCRYPT' and isinstance(cipher, Keyword):
ot_pad = input('Type your one time pad. \n')
keyword_choice = get_keyword()
ot_val = cipher.one_time_pad(user_text, ot_pad)
value = cipher.encrypt(ot_val, keyword_choice)
block_choice = yes_or_no()
if block_choice.upper() == 'Y':
value = cipher.add_padding(value)
print(value + '\n')
repeat()
break
else:
print(value + '\n')
repeat()
break
elif e_or_d.upper() == 'DECRYPT' and isinstance(cipher, Keyword):
ot_pad = input(
'Type your one time pad, must be the same used for encrypting. \n'
)
block_choice = y_o_n()
keyword_choice = get_keyword()
if block_choice.upper() == 'Y':
no_block = cipher.remove_padding(user_text)
value = cipher.decrypt(no_block, keyword_choice)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break
else:
value = cipher.decrypt(user_text, keyword_choice)
ot_val = cipher.one_time_pad(value, ot_pad, encrypt=False)
print(ot_val + '\n')
repeat()
break