Data commit

Task/Chaocipher/Go/chaocipher.go

@@ -0,0 +1,95 @@
+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
+        }
+
+        // permute left
+        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[:])
+
+        // permute right
+
+        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)
+}