ABE in Health Care

Master: Develop:

This repository contains the experiments framework as used in my master's thesis. In this thesis, we try to investigate the feasibility of Attribute Based Encryption (ABE) in a realistic scenario, with requirements for authentication, write access and access revocation.

ABE is an encryption approach in which multiple attributes can be used in a boolean formular to encrypt data. We focus on the so called Ciphertext Policy based ABE (CP-ABE), where the data is encrypted using the attributes, and the keys for the attributes are issued to the users.

Bob, an insured, submits an encrypted photo to an insurance company to be checked by a reviewing doctor in order to qualify for compensation. Only qualified doctors which act as reviewers for this insurance company are allowed to decrypt the ciphertext. Bob encrypts the photo using the policy Reviewer ^ Doctor. Only users who own keys for these attributes are able to decrypt the photo. When the image is reviewed, the access should be revoked. Attributes from multiple authorities are used to describe the role of the users.

For the implementation, the Charm framework is utilized. Part of our contribution involves the implementation of several ABE schemes which could be of interest for our scenario.

Requirements

• Python 3
• Charm (link)

We created a fork from Charm with the added implementations. The fork can be found here.

Charm has its own requirements, see their website for more info.

Python 3 is required because we utilized some new features which are only present in Python 3 (typing).

Installation and tests

• See .travis.yml for up to date details of how to install and execute tests.

Experiments

The different experiments can be found in experiments. All experiments extend BaseExperiment and should define one or more cases of type ExperimentCase.

The ExperimentRunner in experiments_runner.py runs an for all implementations for each case.

Execution

The experiments can be started with:

python main.py

Output

The experiments use a (temporal) location for data storage. This data can be found in data/experiments/{experiment_name}.

The results of the experiments can be found in the results/{experiment_name}/{device_name}/{datetime} directory. The experiments.experiment_output.ExperimentOutput class is responsible for the output of the results.

CPU

Percentage of CPU during entire experiment

Timings

outdated

The .txt file is the result of a dump of pstats.Stats.

The .csv file is this result converted to CSV.

Memory

outdated

rss is what is used, in total, and almost equal to uss,

data is what is available for data only

swap is what is in swap

rss + swap is used mem

See psutil.Process.memory_info.

• rss: aka “Resident Set Size”, this is the non-swapped physical memory a process has used. On UNIX it matches “top“‘s RES column (see doc). On Windows this is an alias for wset field and it matches “Mem Usage” column of taskmgr.exe.
• vms: aka “Virtual Memory Size”, this is the total amount of virtual memory used by the process. On UNIX it matches “top“‘s VIRT column (see doc). On Windows this is an alias for pagefile field and it matches “Mem Usage” “VM Size” column of taskmgr.exe.
• shared: (Linux) memory that could be potentially shared with other processes. This matches “top“‘s SHR column (see doc).
• text (Linux, BSD): aka TRS (text resident set) the amount of memory devoted to executable code. This matches “top“‘s CODE column (see doc).
• data (Linux, BSD): aka DRS (data resident set) the amount of physical memory devoted to other than executable code. It matches “top“‘s DATA column (see doc).
• lib (Linux): the memory used by shared libraries.
• dirty (Linux): the number of dirty pages.
• uss (Linux, OSX, Windows): aka “Unique Set Size”, this is the memory which is unique to a process and which would be freed if the process was terminated right now.
• pss (Linux): aka “Proportional Set Size”, is the amount of memory shared with other processes, accounted in a way that the amount is divided evenly between the processes that share it. I.e. if a process has 10 MBs all to itself and 10 MBs shared with another process its PSS will be 15 MBs.
• swap (Linux): amount of memory that has been swapped out to disk.

Relevant link: What is the simplest and most accurate way to measure the memory used by a program in a programming contest environment?

source:

VIRT stands for the virtual size of a process, which is the sum of memory it is actually using, memory it has mapped into itself (for instance the video card’s RAM for the X server), files on disk that have been mapped into it (most notably shared libraries), and memory shared with other processes. VIRT represents how much memory the program is able to access at the present moment.

RES stands for the resident size, which is an accurate representation of how much actual physical memory a process is consuming. (This also corresponds directly to the %MEM column.) This will virtually always be less than the VIRT size, since most programs depend on the C library.

SHR indicates how much of the VIRT size is actually sharable (memory or libraries). In the case of libraries, it does not necessarily mean that the entire library is resident. For example, if a program only uses a few functions in a library, the whole library is mapped and will be counted in VIRT and SHR, but only the parts of the library file containing the functions being used will actually be loaded in and be counted under RES.