Class for text ciphering.

ciphertext.py

#!/usr/bin/env python3
import base64

class CipherText:
    """Class for text ciphering."""

    KEY_SECRET = "123"

    @staticmethod
    def encrypt(original_text: str) -> str:
        enc = list()
        for i, ch in enumerate(original_text):
            key_c = CipherText.KEY_SECRET[i % len(CipherText.KEY_SECRET)]
            enc_c = chr((ord(ch) + ord(key_c)) % 256)
            enc.append(enc_c)
        encrypted = base64.b64encode("".join(enc).encode()).decode("utf-8")
        return encrypted

    @staticmethod
    def decrypt(encrypted_text: str) -> str:
        dec = list()
        enc = base64.b64decode(encrypted_text).decode()
        for i, ch in enumerate(enc):
            key_c = CipherText.KEY_SECRET[i % len(CipherText.KEY_SECRET)]
            dec_c = chr((256 + ord(ch) - ord(key_c)) % 256)
            dec.append(dec_c)
        original_text = "".join(dec)
        return original_text

if __name__ == "__main__":
    # Testing ...

    original_text  = "Hello world! :-)"

    CipherText.KEY_SECRET = "my-secret-key"

    encrypted_text = CipherText.encrypt(original_text)
    original_text  = CipherText.decrypt(encrypted_text)

    print("encrypted_text:", encrypted_text)
    print("original_text:", original_text)