json-masker-java

A library for masking field values in JSON. Useful when there is a need to log JSON which potentially contains sensitive data such as PII. This project is a port of Node.js json-masker library.

Installation

Described on bintray page

Usage

import com.github.tcdl.jsonmask.JsonMasker;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

//...
JsonNode jsonNode = new ObjectMapper().readTree("{\"a\":1}");
JsonNode masked = new JsonMasker().mask(jsonNode);

Configuration

json-masker-java can be configured via parameters passed into constructor:

whitelist. A collection of whitelisted fields. The values of whitelisted fields will not be masked. Either a field name or a json-path can be specified. Field names are treated case-insensitive. For json-path see documentation. Default: empty collection
enabled. A boolean flag that toggles masking functionality. If set to false, none of the fields will be masked. Might be useful for debug purposes. Default: true

Example

Collection<String> whitelist = Arrays.asList(
        // by field name:
        "field1", 
        "field2",
        // by json-path:
        "$.myArray[1].someField", 
        "$..path.to.a.field"
    );
boolean maskingEnabled = false;
JsonMasker masker = new JsonMasker(whitelist, maskingEnabled);

Masking strategy

Example of input:

{
  "firstName": "Noëlla",
  "lastName": "Maïté",
  "age": 26,
  "gender": "Female",
  "contacts": {
    "email": "cbentson7@nbcnews.com",
    "phone": "62-(819)562-8538",
    "address": "12 Northview Way"
  },
  "employments": [
    {
      "companyName": "Reynolds-Denesik",
      "startDate": "12/7/2016",
      "salary": "$150"
    }
  ],
  "ipAddress": "107.196.186.197"
}

Output:

{
  "firstName": "Xxxxxx",
  "lastName": "Xxxxx",
  "age": "**",
  "gender": "Xxxxxx",
  "contacts": {
    "email": "xxxxxxxx*@xxxxxxx.xxx",
    "phone": "**-(***)***-****",
    "address": "** Xxxxxxxxx Xxx"
  },
  "employments": [
    {
      "companyName": "Xxxxxxxx-Xxxxxxx",
      "startDate": "**/*/****",
      "salary": "$***"
    }
  ],
  "ipAddress": "***.***.***.***"
}

Rules

strings
- whitespaces remain unchanged
- punctuation marks (non-alphanumeric characters of latin-1) remain unchanged
- latin-1 characters 1-9 become *
- latin-1 characters A-Z become X
- all other UTF-8 characters become x
numbers are converted to strings where each 1-9 character is replaced with * (e.g. 125 becomes "***" or 3.95 becomes "*.**")
booleans: remain unchanged
nulls: remain unchanged

Tests

To run unit tests you can just execute:

mvn test

from project's root directory.

Benchmark

JMH framework is used for benchmarking. To run performance tests:

cd benchmark/jsonmask-java-benchmark
mvn package
java -jar target/benchmarks.jar

tcdl / json-masker-java