Is there a better way to mask a Credit Card number in python?

Question

So I have a csv file that contains full credit-card numbers.. We dont need the full number, and so I am writing a quick script to parse through the csv and replace the cc number with a masked representation. (all *'s except the last four). I am pretty new to python and hacked this up, and it works, but in order to learn I want to know if it could be done easier.

Assume that "str" will be a full creditcard number. But for the sake of my example I am just using the string "CREDITCARDNUMBER".

str = "CREDITCARDNUMBER";
strlength = len(str)
masked = strlength - 4
slimstr = str[masked:]
print "*" * masked + slimstr

The output is exactly what I want

************MBER

But I am sure there is a more elegant solution. :) Thanks!

Christianly

by looking at this i'm guessing you an shorter the code 1~2 lines – Odelia

why not just print the last 4 numbers? are the asterisks necessary? – Jenness

You might want to accept one of these answers – Geostatic

So far I wouldn't call the answers more "elegant". They are shorter, but a bit cryptic I think. In general I might prefer the code in the question for readability. – Rayerayfield

Answer 1

Neater still:

>>> s = "CREDITCARDNUMBER"
>>> s[-4:].rjust(len(s), "*")
'************MBER'

Kinetics

Answer 2

Perhaps slightly more elegant:

card = "CREDITCARDNUMBER"
print ("*" * (len(card) - 4) + card[-4:])

Note that I've avoided using the name str because that is already the name of the built-in string type. It's usually not a good idea to use names that shadow the built-in names.

Bassist

Answer 3

For those who want to keep Issuer Identification Number (IIN) (previously called the "Bank Identification Number" (BIN)), which is usually the first 6 digits, that should do the job:

print card[:6] + 'X' * 6 + card[-4:]
'455694XXXXXX6539'

Offing

Answer 4

With Format String and Slicings:

'{:*>16}'.format(card[-4:])

Chalmer

sweet!, i modified it a bit to deal with dynamic length ('{:*>'+str(len(card) - 4)+'}').format(card[-4:]) – Dated

Answer 5

You could make it a little shorter like so:

str = "CREDITCARDNUMBER";
print "*" * (len(str) - 4) + str[-4:];

Corvus

Answer 6

I wanted a flexible way to mask stuff, so I thought I'd share ...

def mask(string, start=0, end=0, chunk=4, char="*"):

    if isinstance(string, str):

        string_len = len(string)

        if string_len < 3:
            return "input len = {}, what's the point?".format(string_len)

        if start <= 0 or end <= 0:
            start = string_len // chunk
            end = start

        if string_len <= 4:
            mask_len = string_len // 2
            start = 1 if mask_len - 1 == 0 else mask_len - 1
            end = start
        else:
            mask_len = string_len - abs(start) - abs(end)

        return string[:abs(start)] + (char * mask_len) + string[-end:]



if __name__ == "__main__":

    s = "abcdefghijklmnopqrstuvwxyz01234567890a0b0c0d0e0f1a1b1c1d1e1f2a2b"
    l = [i for i in s]
    message = "ip: {}\nop: {}\n"
    section = "-"*79

    print("\nSTRINGS")
    print(section)
    print(message.format(s[:4], mask(s[:4])))
    print(message.format(s[:3], mask(s[:3])))
    print(message.format(s[:2], mask(s[:2])))
    print(message.format(s, mask(s)))
    print(message.format(s, mask(s,start=2,end=4,char="#")))
    print(message.format(s, mask(s,start=3,end=3,char="x")))

Photogram

Answer 7

I think you can get a decently readable solution without worrying about the len of the str using a simple regex replace and two string slices:

import re
str = 'CREDITCARDNUMBER'
print(re.sub('.', '*', str[:-4]) + str[-4:])

I am not sure this is more "elegant" than the original, but there it is.

Rayerayfield

Answer 8

We also can use this function:

def maskify(cc):
    if len(cc) < 4:
        return cc
    return "#" * (len(cc)-4) + cc[-4:]

Disini

Answer 9

#Simple code to mask 16-digit credit card number

def cardNumberHider():
    str = input("Enter the card number: ")
    masked = len(str) - 4
    slimstr = str[masked:]
    print("Your masked card number is: ", end="")
    print("*" * masked + slimstr)
cardNumberHider()

Rogerrogerio

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Answer 10

You could also simplify it further with this:

input = str(input("Enter your credit card number (one continuous number): "))
x = input[12:16]
print("************" + x)

Final