Caesar's Cipher using python, could use a little help

Question

I\'m trying to make a \"Caesar\'s Cipher\" while using python..this is what I have so far. Could anyone tell me how this is looking? Am I going in the right direction? What

Answer 1

This code should work pretty well. It also handles arbitrary offsets, including negative.

phrase = raw_input("Please enter plaintext to Cipher: ")
shift = int(raw_input("Please enter shift: "))

result = ''
for char in phrase:
    x = ord(char)

    if char.isalpha():
        x = x + shift

        offset = 65
        if char.islower():
            offset = 97

        while x < offset:
            x += 26

        while x > offset+25:
            x -= 26

        result += chr(x)

print result

The other way to do it, with a slightly different cipher, is simply rotate through all characters, upper and lower, or even all ascii > 0x20.

phrase = raw_input("Please enter plaintext to Cipher: ")
shift = int(raw_input("Please enter shift: "))

result = ''
for char in phrase:
    x = ord(char)

    x = x + shift

    while x < 32:
        x += 96

    while x > 127:
        x -= 96

    result += chr(x)

print result

Answer 2

I like kaizer.se's answer, but I think I can simplify it using the string.maketrans function:

import string

first = raw_input("Please enter Plaintext to Cipher: ")
k = int(raw_input("Please enter the shift: "))

shifted_lowercase = ascii_lowercase[k:] + ascii_lowercase[:k]

translation_table = maketrans(ascii_lowercase, shifted_lowercase)

print first.translate(translation_table)

Answer 3

Barring the syntax errors, your code seems to work.

However, I took the liberty of removing all duplicates, and cleaning it up:

first = raw_input("Please enter Plaintext to Cipher: ")
k = int(raw_input("Please enter the shift: "))

result = ''
for second in first:
    x=ord(second)
    x=x+k
    if x>90 and x<122:
        x=x-26
    elif x>122:
        x=x-26
    result += chr(x)

print first    
print result

Also "first" and "second" are really bad names for those variables. "Input" and "letter" is probably better.

Answer 4

Here is a oneliner.

>>> brutus=lambda message,cipher,direction:''.join([chr((ord(letter)+(cipher*direction))%256) for letter in message])
>>> encrypted= brutus('Message to be encrypted',14,1) #direction=1 for encryption
>>> encrypted
'[s\x81\x81ous.\x82}.ps.s|q\x80\x87~\x82sr'
>>> brutus(encrypted,14,-1) # direction=-1 for decryption
'Message to be encrypted'
>>>

Answer 5

For Python 3.3, try using the ord(), chr() and .isalpha functions:

m = input("What is your message?: ")
s = int(input("What is the shift?: "))
for i in m:
    if i.isalpha():
        if (ord(i)+s)>90:
            print(chr(ord(i)+s-26),end=""),
        elif chr(ord(i)+s-26)<65:
            print("The shift is invalid")
        else:
            print(chr(ord(i)+s),end=""),
    else:
        pass

Answer 6

Put a comma after each print statement; it will still put a space between the characters, but they'll all be on the same line. If you need to print them without the spaces, build them all into a single string and print that at the end.