Task: Chaocipher
Go: package main

import(
    "fmt"
    "strings"
    "unicode/utf8"
)

type Mode int

const(
    Encrypt Mode = iota
    Decrypt
)

const(
    lAlphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
    rAlphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
)

func Chao(text string, mode Mode, showSteps bool) string {
    len := len(text)
    if utf8.RuneCountInString(text) != len {
        fmt.Println("Text contains non-ASCII characters")
        return ""
    }
    left  := lAlphabet
    right := rAlphabet
    eText := make([]byte, len)
    temp  := make([]byte, 26)

    for i := 0; i < len; i++ {
        if showSteps {
            fmt.Println(left, " ", right)
        }
        var index int
        if mode == Encrypt {
            index = strings.IndexByte(right, text[i])
            eText[i] = left[index]
        } else {
            index = strings.IndexByte(left, text[i])
            eText[i] = right[index]
        }
        if i == len - 1 {
            break
        }

        
        for j := index; j < 26; j++ {
            temp[j - index] = left[j]
        }
        for j := 0; j < index; j++ {
            temp[26 - index + j] = left[j]
        }
        store := temp[1]
        for j := 2; j < 14; j++ {
            temp[j - 1] = temp[j]
        }
        temp[13] = store
        left = string(temp[:])

        

        for j := index; j < 26; j++ {
            temp[j - index] = right[j]
        }
        for j := 0; j < index; j++ {
            temp[26 - index + j] = right[j]
        }
        store = temp[0]
        for j := 1; j < 26; j++ {
            temp[j - 1] = temp[j]
        }
        temp[25] = store
        store = temp[2]
        for j := 3; j < 14; j++ {
            temp[j - 1] = temp[j]
        }
        temp[13] = store
        right = string(temp[:])
    }

    return string(eText[:])
}

func main() {
    plainText := "WELLDONEISBETTERTHANWELLSAID"
    fmt.Println("The original plaintext is :", plainText)
    fmt.Print("\nThe left and right alphabets after each permutation ")
    fmt.Println("during encryption are :\n")
    cipherText := Chao(plainText, Encrypt, true)
    fmt.Println("\nThe ciphertext is :",  cipherText)
    plainText2 := Chao(cipherText, Decrypt, false)
    fmt.Println("\nThe recovered plaintext is :", plainText2)
}

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