New encryption algorithm - Columnar Transposition

.gitignore

@@ -11,4 +11,5 @@ dist/
 build/
 *.egg-info/
 
-.env
+.env
+.vscode

encryptor/__init__.py

@@ -164,6 +164,35 @@ def aes_decrypt(text):
             "content": Aes.decrypt(text, key, nonce)
         })
 
+    @app.route("/api/transposition/encrypt")
+    def transposition_encrypt():
+        key = request.args.get("key")
+        if key:
+            key = int(key)
+        else:
+            key = 0
+        message = request.args.get("text")
+        return jsonify({
+            "status": 200,
+            "content": Transposition.encrypt(key, message)
+        })
+
+
+    @app.route("/api/transposition/decrypt")
+    def transposition_decrypt():
+        key = int(request.args.get("key",0))
+        key = request.args.get("key")
+        if key:
+            key = int(key)
+        else:
+            key = 0
+        message = request.args.get("text")
+        message = request.args.get("text")
+        return jsonify({
+            "status": 200,
+            "content": Transposition.decrypt(key, message)
+        })
+
 
     @app.route("/api/error")
     def trigger_error():

encryptor/encryptors/__init__.py

@@ -4,3 +4,4 @@
 from .vigenere import *
 from .rsa import *
 from .aes import *
+from .transposition import *

encryptor/encryptors/transposition.py

@@ -0,0 +1,41 @@
+import math
+from flask import jsonify
+
+class Transposition:
+
+    @staticmethod
+    def encrypt(key, message):
+        ciphertext = [] 
+        for col in range(key):
+            position = col
+            while position < len(message):
+                ciphertext.append(message[position])
+                position += key
+        return ''.join(ciphertext)
+
+    @staticmethod
+    def decrypt(key, message):
+        numOfRows = math.ceil(len(message) / key)
+        plaintext = []
+        cipher = [*message]
+        remainder = len(message)%key
+        count=0
+        if(remainder != 0):
+            for i in range(0,len(message),numOfRows):
+                count += 1
+                if(count > remainder):
+                    cipher.insert(i+numOfRows-1,'#')
+            cipher.append('#')
+            for row in range(numOfRows):
+                position = row
+                while(position < len(cipher)):
+                    plaintext.append(cipher[position])
+                    position += numOfRows
+            plaintext = [ele for ele in plaintext if ele != '#']
+        else:
+            for row in range(numOfRows):
+                position = row
+                while(position < len(message)):
+                    plaintext.append(message[position])
+                    position += numOfRows
+        return ''.join(plaintext)

tests/api/api_transposition_test.py

@@ -0,0 +1,11 @@
+import pytest
+
+def test_transposition_encrypt_api(client):
+    response = client.get("/api/transposition/encrypt?key=3&text=test text").get_json()
+    assert response["status"] == 200
+    assert response["content"] == "ttee xstt"
+
+def test_transposition_decrypt_api(client):
+    response = client.get("/api/transposition/decrypt?key=3&text=ttee xstt").get_json()
+    assert response["status"] == 200
+    assert response["content"] == "test text"

tests/encryptors/transposition_test.py

@@ -0,0 +1,8 @@
+import pytest
+from encryptor.encryptors import Transposition
+
+def test_encrypt():
+    assert Transposition.encrypt(3, "TEST MESSAGE") == "TTEAE SGSMSE"
+
+def test_decrypt():
+    assert Transposition.decrypt(3, "TTEAE SGSMSE") == "TEST MESSAGE"