100LinesOfCode/Encryption/enc.py at master · josharsh/100LinesOfCode · GitHub

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import base64
import binascii
import string
import re


#Check if a given string consists only of valid hexadecimal characters.
def isHex(message):
    for char in message:
        if char not in string.hexdigits:
            return False
    return True

# Check if a given string or bytes object is valid Base64.
def is_base64(message):
     # If bytes decode to string
    if isinstance(message, bytes):
        try:
            message = message.decode("utf-8")
        except UnicodeDecodeError:
            return False

    #The total length of the Base64 encoded string is always divisible by 4
    if len(message) % 4!= 0:
        return False
    #It consists of uppercase letters (A-Z), lowercase letters (a-z), numbers (0-9), and the symbols '+' and '/'
    if not re.fullmatch(r'^[A-Za-z0-9+/]*={0,2}$', message):
        return False
    #Check for correct padding
    try:
        base64.b64decode(message, validate=True)
        return True
    except Exception:
        return False


# ~~~~~~~~~~~~~~~~~~~~~~ Encryption ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
message = input("Please enter the text you would like to encrypt ")


option = input("Please select the method you'd like to use: base64/morse/hex/caesar cipher: ")
if option == 'base64' or option == 'morse' or option == 'hex' or option == 'caesar cipher':
    if option == 'base64':
            message_bytes = message.encode('ascii')
            base64_bytes = base64.b64encode(message_bytes)
            base64_message = base64_bytes.decode('ascii')
            print("Encrypted Message:" + base64_message)


    if option == 'morse':
        Morse_Dict = {'A':'.-', 'B':'-...','C':'-.-.', 'D':'-..', 'E':'.','F':'..-.', 'G':'--.', 'H':'....','I':'..', 'J':'.---', 'K':'-.-','L':'.-..', 'M':'--', 'N':'-.','O':'---', 'P':'.--.', 'Q':'--.-','R':'.-.', 'S':'...', 'T':'-','U':'..-', 'V':'...-', 'W':'.--','X':'-..-', 'Y':'-.--', 'Z':'--..','1':'.----', '2':'..---', '3':'...--','4':'....-', '5':'.....', '6':'-....','7':'--...', '8':'---..', '9':'----.','0':'-----', ', ':'--..--', '.':'.-.-.-','?':'..--..', '/':'-..-.', '-':'-....-','(':'-.--.', ')':'-.--.-'}

        def encryption(message):
            cipher = ''
            for letter in message:
                if letter != ' ':
                    if letter.upper() not in Morse_Dict:
                        raise SystemExit(f"Unsupported character: {letter}") #Εrror handling for unsupported characters

                    cipher += Morse_Dict.get(letter.upper(), '') + ' ' #With that the message can contain lower case letters
                else:
                    cipher += ' '
            print(cipher)
        encryption(message)


    if option == 'hex':
        print(message.encode("utf-8").hex())

    if option == 'caesar cipher':
        s = int(input("Please enter the shift number you'd like (Exmaple: 4): "))
        def encrypt(message,s):
            result = ""
            # transverse the plain text
            for i in range(len(message)):
                char = message[i]
                # Encrypt uppercase characters in plain text

                if (char.isupper()):
                    result += chr((ord(char) + s-65) % 26 + 65)
                # Encrypt lowercase characters in plain text
                else:
                    result += chr((ord(char) + s - 97) % 26 + 97)
            print(result)
        encrypt(message, s)


# ~~~~~~~~~~~~~~~~~~~~~~ DECRYPTION ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
message = input("Please enter the text you would like to decrypt ")
option = input("Please select the method you'd like to use: base64/morse/hex/caesar cipher: ")
if option == 'base64' or option == 'morse' or option == 'hex' or option == 'caesar cipher':
    if option == 'base64':
            message_bytes = message.encode('ascii')
            if is_base64(message_bytes):
                base64_bytes = base64.b64decode(message_bytes)
                base64_message = base64_bytes.decode('ascii')
                print("Encrypted Message:" + base64_message)
            else:
                print("The text is not a valid base64 string")


    if option == 'morse':
        Morse_Dict = {'A':'.-', 'B':'-...','C':'-.-.', 'D':'-..', 'E':'.','F':'..-.', 'G':'--.', 'H':'....','I':'..', 'J':'.---', 'K':'-.-','L':'.-..', 'M':'--', 'N':'-.','O':'---', 'P':'.--.', 'Q':'--.-','R':'.-.', 'S':'...', 'T':'-','U':'..-', 'V':'...-', 'W':'.--','X':'-..-', 'Y':'-.--', 'Z':'--..','1':'.----', '2':'..---', '3':'...--','4':'....-', '5':'.....', '6':'-....','7':'--...', '8':'---..', '9':'----.','0':'-----', ', ':'--..--', '.':'.-.-.-','?':'..--..', '/':'-..-.', '-':'-....-','(':'-.--.', ')':'-.--.-'}
        def decrypt(message):
            var = '' #variable for concatenating letters
            decode = ''
            for letter in message:
                if (letter != ' '):
                    c = 0          #counter for spaces to keep letters separated
                    var += letter
                else:
                    c += 1
                    if c == 2:
                        decode += ' '
                    else:
                        decode += list(Morse_Dict.keys())[list(Morse_Dict.values()).index(var)]
                        var = ''
            return decode
        result = decrypt(message)
        print (result)


    if option == 'hex':
        #Here we have to check if the given string for decryption is actually a hex string
        if isHex(message):
            hex_bytes = bytes.fromhex(message)
            message_bytes = hex_bytes.decode('utf-8')
            result = message_bytes
            print(result)

        else:
            print("The text is not a valid hexadecimal string")

    if option == 'caesar cipher':
        s = int(input("Please enter the shift number you'd like (Exmaple: 4): "))
        def decrypt2(message,s):
            result = ""
            # transverse the plain text
            for i in range(len(message)):
                char = message[i]
                # Encrypt uppercase characters in plain text

                if (char.isupper()):
                    result += chr((ord(char) - s-65) % 26 + 65)
                # Encrypt lowercase characters in plain text
                else:
                    result += chr((ord(char) - s - 97) % 26 + 97)
            print(result)
        decrypt2(message, s)