Task: Chaocipher







Python: 



def main():
    
    lalpha = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
    ralpha = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
    msg = "WELLDONEISBETTERTHANWELLSAID"

    print("L:", lalpha)
    print("R:", ralpha)
    print("I:", msg)
    print("O:", do_chao(msg, lalpha, ralpha, 1, 0), "\n")
    
    do_chao(msg, lalpha, ralpha, 1, 1)

def do_chao(msg, lalpha, ralpha, en=1, show=0):
    msg = correct_case(msg)
    out = ""    
    if show:
        print("="*54)        
        print(10*" " + "left:" + 21*" " + "right: ")
        print("="*54)        
        print(lalpha, ralpha, "\n")
    for L in msg:
        if en:
            lalpha, ralpha = rotate_wheels(lalpha, ralpha, L)
            out += lalpha[0]
        else:
            ralpha, lalpha = rotate_wheels(ralpha, lalpha, L)
            out += ralpha[0]
        lalpha, ralpha = scramble_wheels(lalpha, ralpha)
        if show:
            print(lalpha, ralpha)            
    return out
    
def makealpha(key=""):
    alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    z = set()
    key = [x.upper() for x in (key + alpha[::-1])
           if not (x.upper() in z or z.add(x.upper()))]
    return "".join(key)

def correct_case(string):
    return "".join([s.upper() for s in string if s.isalpha()])

def permu(alp, num):
    alp = alp[:num], alp[num:]
    return "".join(alp[::-1])

def rotate_wheels(lalph, ralph, key):
    newin = ralph.index(key)
    return permu(lalph, newin), permu(ralph, newin)    

def scramble_wheels(lalph, ralph):
    
    
    lalph = list(lalph)
    lalph = "".join([*lalph[0],
                    *lalph[2:14],
                    lalph[1],
                    *lalph[14:]])
    
    
    
    
    ralph = list(ralph)
    ralph = "".join([*ralph[1:3],
                     *ralph[4:15],
                     ralph[3],
                     *ralph[15:],
                     ralph[0]])
    return lalph, ralph

main()


VB: Module Module1

    ReadOnly L_ALPHABET As String = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
    ReadOnly R_ALPHABET As String = "PTLNBQDEOYSFAVZKGJRIHWXUMC"

    Enum Mode
        ENCRYPT
        DECRYPT
    End Enum

    Function Exec(text As String, mode As Mode, Optional showSteps As Boolean = False) As String
        Dim left = L_ALPHABET.ToCharArray()
        Dim right = R_ALPHABET.ToCharArray()
        Dim eText(text.Length - 1) As Char
        Dim temp(25) As Char

        For i = 0 To text.Length - 1
            If showSteps Then Console.WriteLine("{0} {1}", String.Join("", left), String.Join("", right))
            Dim index As Integer
            If mode = Mode.ENCRYPT Then
                index = Array.IndexOf(right, text(i))
                eText(i) = left(index)
            Else
                index = Array.IndexOf(left, text(i))
                eText(i) = right(index)
            End If
            If i = text.Length - 1 Then Exit For

            

            For j = index To 25
                temp(j - index) = left(j)
            Next
            For j = 0 To index - 1
                temp(26 - index + j) = left(j)
            Next
            Dim store = temp(1)
            For j = 2 To 13
                temp(j - 1) = temp(j)
            Next
            temp(13) = store
            temp.CopyTo(left, 0)

            

            For j = index To 25
                temp(j - index) = right(j)
            Next
            For j = 0 To index - 1
                temp(26 - index + j) = right(j)
            Next
            store = temp(0)
            For j = 1 To 25
                temp(j - 1) = temp(j)
            Next
            temp(25) = store
            store = temp(2)
            For j = 3 To 13
                temp(j - 1) = temp(j)
            Next
            temp(13) = store
            temp.CopyTo(right, 0)
        Next

        Return eText
    End Function

    Sub Main()
        Dim plainText = "WELLDONEISBETTERTHANWELLSAID"
        Console.WriteLine("The original plaintext is : {0}", plainText)
        Console.WriteLine(vbNewLine + "The left and right alphabets after each permutation during encryption are :" + vbNewLine)
        Dim cipherText = Exec(plainText, Mode.ENCRYPT, True)
        Console.WriteLine(vbNewLine + "The ciphertext is : {0}", cipherText)
        Dim plainText2 = Exec(cipherText, Mode.DECRYPT)
        Console.WriteLine(vbNewLine + "The recovered plaintext is : {0}", plainText2)
    End Sub

End Module