Change of masking mechanism

[zbalkan]

Generally PAN is masked excluding the first 6 and last 4 numbers, allowing further investigations. The line below fully replaces the number with as substitute.

fluent-plugin-pan-anonymizer/lib/fluent/plugin/pan/masker.rb

Line 38 in 0e021c4

match = @mask

It would be better to allow the masking to be configurable like this:

  <pan>
    # mastercard
    formats /(5[1-5][0-9]{2}(?:\ |\-|)[0-9]{2})[0-9]{2}(?:\ |\-|)[0-9]{4}(?:\ |\-|)([0-9]{4})/
    checksum_algorithm luhn
    mask \\1******\\2
  </pan>

This can be possible by changing the replacement code:

 match = match.gsub(@regexp, @mask)