Scytale cipher added

[LuminousLizard]

I wrote a algorithm for the Scytale Cipher if you want to use it for your package. Maybe the algorithm can be written shorter/prettier because I'm a programming novice .... but it works.

LuminousLizard

[tigertv]

Hi, @LuminousLizard, thanks for the PR! I think it would be useful, but it breaks down on Python 2.7. Yeah, I'm still supporting it.

[LuminousLizard]

[...] but it breaks down on Python 2.7. [...]

I never worked with Python2 but I think it's because line 28 und 46 with ceil(len(text) / key) .. right ?! In Python3 ceil(16 / 5) = 4 <- the desired result In Python2 ceil(16 / 5) = 3

I'm looking for a solution

[tigertv]

I get the following on Python 2.7:

ciphers/scytale.py", line 29, in __enc
    for block_count in range(0, ceil(len(text) / key)):
TypeError: range() integer end argument expected, got float.

Also when I execute the code(Python 3) with key = 4

from secretpy import Scytale, CryptMachine
from secretpy import alphabets

def encdec(machine, plaintext):
    print(plaintext)
    enc = machine.encrypt(plaintext)
    print(enc)
    print(machine.decrypt(enc))
    print("-------------------------------")

key = 4
cm = CryptMachine(Scytale(), key)
plaintext = "I am hurt very badly help".replace(' ', '').lower()
encdec(cm, plaintext)

I'm getting not the same result from wiki ("iryyatbhmvaehedlurlp"):

iamhurtverybadlyhelp
iueaharrdemtyllhvbyp
iamhurtverybadlyhelp
-------------------------------

[LuminousLizard]

ciphers/scytale.py", line 29, in __enc for block_count in range(0, ceil(len(text) / key)): TypeError: range() integer end argument expected, got float.

Because e.g.: in python2 => "floor(16/5) = 3.0" in python3 => "floor(16/5) = 3"

I added an explicit conversion to int to fix it. I tested it with python2.7 and python3.9 and it works.

I'm looking for the wrong result ....

[tigertv]

in python2 => "floor(16/5) = 3.0"
in python3 => "floor(16/5) = 3"

There is an operator //:

16 // 5 = 3

[LuminousLizard]

Contains mistakes

[tigertv]

@LuminousLizard, that's not a problem. I suppose you can fix it. I will add your code after that.