ARBoR (Authenticated Resources in Hashed Block Registry)

Clinical laboratories return the results of clinical testing to the ordering physician as a signed report. This report is often a PDF, but can also be a physical paper copy or a structured data format. Here, we present ARBoR, a simple and efficient approach that addresses the difficulties of monitoring report authenticity by providing a record of cryptographically signed, versioned reports, stored in a replicated ledger. This approach augments the secure delivery path between clinical labs and a downstream Electronic Health Record (EHR) system by providing a durable method to verify the authenticity of files and detect whether newer files are known to exist. More details at ARBoR.

The overall ARBoR system consists of three parts:

• ARBoR Service (ledger_generator.py) stores records in a public ledger. It only accepts trusted records from the clinical pipeline.
• ARBoR Client (ledger_validator.py) is typically run by an institutional end user as part of the ingestion process for new clinical reports and related files. It fetches new blocks from the ARBoR Service and uses its local copy of the ledger to validate and identify files.
• ARBoRScan is a mobile app for both iOS and Android platforms and is typically run by an end user to fetch metadata about existing reports and check the authenticity and versions of these reports. It also maintains a local copy of the ledger. It's primary input is scanning QR codes from existing reports.

ARBoR is built using Python and is available for public use. Instructions on building a ledger and validating the contents of a ledger are provided.

Requirements:

• Python:
  • 2.7
  • 3.6
  • 3.7
• Packages:
  • Beautiful Soup 4.6+
  • PyCrypto 2.6+
• Ledger File (eg. arbor-ledger.json)
• Public Key (eg. arbor-public.key)

Installation

Using pip to install into the active environment:

pip install -r requirements.txt

Using conda to install into the active environment using user channel settings:

conda install --file requirements.txt

Using conda to create a new environment:

conda create -c defaults --override-channels -n py37-arbor python=3.7 --file requirements.txt

Usage:

Generating the ledger

To generate a ledger, pass in a directory of reports and a private key. The generator currently requires XML files that provide the metadata for associated PDF files. This command will generate a ledger for all files in a folder:

python ledger_generator.py -h  # for help
python ledger_generator.py --ledger=arbor-ledger.json --privatekey=arbor-private.key --publickey=arbor-public.key --recursive reportdir/

Verifying that a file is current and unaltered

To verify files against a ledger, pass in either individual files or directories along with a public key that corresponds to the private key used when generating the ledger. Running the following command on a folder of reports or a single report will identify if the report(s) are valid and up to date:

python ledger_validator.py -h  # for help
python ledger_validator.py --ledger=arbor-ledger.json --publickey=arbor-public.key --check-latest reportdir

Automated Testing

Testing also requires pytest:

Using conda:

conda install pytest

Using pip:

pip install pytest

Execution:

pytest