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First solution in Clear category for Scytale Encryption by akitspace
from typing import Optional
def scytale_decipher(ciphertext: str, crib: str) -> Optional[str]:
res = []
for step in range(1,len(ciphertext)):
text = ''.join([chr for start in range(step) for chr in (ciphertext)[start::step]])
if crib in text:
res.append(text)
if len(res) == 1:
return res[0]
if __name__ == "__main__":
print("Example:")
print(scytale_decipher("aaaatctwtkdn", "dawn"))
# These "asserts" are used for self-checking and not for an auto-testing
assert scytale_decipher("aaaatctwtkdn", "dawn") == "attackatdawn"
assert scytale_decipher("hdoeerlallrdow", "world") == "hellodearworld"
assert (
scytale_decipher("totetshpmeecisendysescwticsriasraytlaegphet", "sicret")
== None
), "Crib is not in plaintext"
assert (
scytale_decipher("aaaatctwtkdn", "at") == None
), "More than one possible decryptions"
print("Coding complete? Click 'Check' to earn cool rewards!")
Jan. 19, 2022
