CardRedactor

A gem for detecting sensitive credit card PANs in strings, and redacting them. All digits, except the trailing 4, are replaced with X. The original format of the number is kept intact. Supports Visa, Mastercard, AMEX, and Discover. Useful for cases where user input may inadvertently contain credit card numbers, and you want to ensure they aren't stored.

Installation

Add this line to your application's Gemfile:

gem 'card_redactor', '~> 1.0.0'

And then execute:

$ bundle

Or install it yourself as:

$ gem install card_redactor

Usage

Firstly, CardRedactor can be used to detect the presence of a credit card PAN in a string:

>> card = "4111-1111-1111-1111"
=> "4111-1111-1111-1111"
>> CardRedactor.contains_card?(card)
=> true

Secondly, you can redact those PANs, replacing all but the last 4 digits with Xs:

>> CardRedactor.redact(card)
=> "XXXX-XXXX-XXXX-1111"

It'll work with natural language sentences, and leave numbers that aren't credit cards alone:

>> card = "A more complex example, with an NZ bank account 12-1212-343434-01 and a credit card 4111111111111111, wow!"
=> "A more complex example, with an NZ bank account 12-1212-343434-01 and a credit card 4111111111111111, wow!"
>> CardRedactor.contains_card?(card)
=> true
>> CardRedactor.redact(card)
=> "A more complex example, with an NZ bank account 12-1212-343434-01 and a credit card XXXXXXXXXXXX1111, wow!"

and strings that contain more than one PAN:

>> card = "I've got 4111111111111111 and 3759-876513-21001"
=> "I've got 4111111111111111 and 3759-876513-21001"
>> CardRedactor.redact(card)
=> "I've got XXXXXXXXXXXX1111 and XXXX-XXXXXX-X1001"

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/pocketsmith/card-redactor.