iframe-proxy | Sunbelt Computer Software

37 lines (29 loc) · 826 Bytes

def dencrypt(s: str, n: int = 13):

"""

https://en.wikipedia.org/wiki/ROT13

>>> msg = "My secret bank account number is 173-52946 so don't tell anyone!!"

>>> s = dencrypt(msg)

>>> s

"Zl frperg onax nppbhag ahzore vf 173-52946 fb qba'g gryy nalbar!!"

>>> dencrypt(s) == msg

True

"""

out = ""

for c in s:

if "A" <= c <= "Z":

out += chr(ord("A") + (ord(c) - ord("A") + n) % 26)

elif "a" <= c <= "z":

out += chr(ord("a") + (ord(c) - ord("a") + n) % 26)

else:

out += c

return out

def main():

s0 = input("Enter message: ")

s1 = dencrypt(s0, 13)

print("Encryption:", s1)

s2 = dencrypt(s1, 13)

print("Decryption: ", s2)

if __name__ == "__main__":

import doctest

doctest.testmod()

main()

Sunbelt Computer Software