json-salt

json-salt is a command-line tool written in Go that reads in arbitrary valid JSON from a file and given a particular key string will salt and hash it in a standard manner.

The goal is to obfuscation/pseudo-anonymisation|anonymization with a consistent method. This tool was built in the light of hashing identifying information to profile users across disparate data sources for further group analysis.

• Information
  • Limitations
• Usage
  • Arguments
  • Switches
• Limitations
• Examples

Information

Currently, json-salt outputs by default in JSON line format because it's typically easier to handle than pretty printed JSON.

The hashing method implemented is md5. The salting method implemented is basic and prepends the salt like so:

yoursaltkeyvalue

Limitations & Possible Bugs

• Only hashes one key per run, usually one field is enough to identify a user across multiple disparate datasets
• Only one method for salting currently by pre-pending the salt, custom pattern flag could be implemented
• Only md5sum hashing has been implemented, other hashing methods could be implemented
• Has not been tested with referencing keys, objects or JSON documents inside arrays
• Has not been tested with first level fields that require hashing

Let me know what doesn't work for you in the issues page.

Usage

Currently json-salt outputs the hashed JSON to stdout and prints program information to stderr. If it has troubles decoding JSON it will probably freak out.

Arguments

Flag	Example	Description
-f	/path/to/file.json	Specify the path to the JSON file to salt and hash.
-k	outer.inner.third.key	The path to the key name to hash, separated by delimiter for nested keys`.
-s	astringofsalt	Salt to hash the value with.
-d	.	Specify custom delimiter for nested key path in case you have dots in your field names, dot delimiter by default.

Switches

Flag	Description
-h	Displays the usage information.
-lc	Convert key value to lower-case before hashing.
-uc	Convert key value to upper-case before hashing.
-w	Strip trailing and leading white-space on key value before hashing.
-pretty	Pretty print the JSON output instead of JSON lines.k
-version	Print the program version.

Examples

Run json-salt without the salt flag and it will prompt you to enter it without echoing the salt to the terminal:

~$ json-salt -k source.user.uid -w -lc -f ~/path/to/file.json > outputfile.json
Enter salt to hash with: 

Run json-salt with the salt flag to batch hash a series of JSON files:

~$ for file in *.json; do json-salt -k source.user.uid -f $file -s yoursalt > ${file/.json/-hashed.json}