bc-lifehash - The C++/C Implementation
- part of the crypto commons technology family
Watch the LifeHash explainer video!
LifeHash is a method of hash visualization based on Conway’s Game of Life that creates beautiful icons that are deterministic, yet distinct and unique given the input data.
The basic concept is to take a SHA256 hash of the input data (which can be any data including another hash) and then use the 256-bit digest as a 16x16 pixel "seed" for running the cellular automata known as Conway’s Game of Life.
After the pattern becomes stable (or begins repeating) the resulting history is used to compile a grayscale image of all the states from the first to last generation. Using Game of Life provides visual structure to the resulting image, even though it was seeded with entropy.
Some bits of the initial hash are then used to deterministically apply symmetry and color to the icon to add beauty and quick recognizability.
Notes on This Implementation
We intend this C++/C implementation to become the "canonical" implementation, and to be suitable for binding to other languages such as Java, Python, and cross-compilation into WebAssembly. In order to work from a single main codebase, we also expect this implementation to eventually replace the pure Swift implementation.
bc-lifehash-cli is a command line tool written in C++ that generates LifeHash images as PNG files.
The LifeHash library is self-contained and has no dependencies.
$ ./build.sh $ sudo make install
Note: If on Linux, you'll have to install
$ sudo apt-get install zsh
- Link against
- Include the umbrella header in your code:
The output image structure contains the image width and height, and an array of RGB byte tuples in row-major order starting from the upper-left corner. The caller is responsible for translating this structure into a displayable format.
LifeHashes In Five Flavors
version1The Original. DEPRECATED
version2Bug fixes and CMYK-friendly.
detailedNow with twice the resolution, and CMYK-friendly.
fiducialFiducials are symbols specifically optimized for recognition by machine vision algorithms like those in Apple's ARKit. Now CMYK-friendly.
grayscaleFiducialHighest contrast for low-light situations.
Version 1 (DEPRECATED)
From the "LifeHash Example" demo app:
"LifeHash Example" (part of the Swift implementation) lets you scroll through an endless table of LifeHashes generated from sequential integers, and tap on any of them to get a closer look. The selector at the top lets you choose to browse
From the "LifeHash Gallery" demo app:
"LifeHash Gallery" shows an elegant, artistic presentation of various collections of LifeHashes that automatically change every ten seconds. The latest version shows
From the Mathematica implementation:
Tips for Presenting LifeHash Images
- Don't vignette or round the corners of a LifeHash image, every pixel contributes to the security of the image, so show the image as a square. If you really want to round the corners, make the radius small enough to still show the corner pixels.
- Don't interpolate or blur a LifeHash image: show every pixel crisply. On iOS UIKit this is accomplished by setting
layer.magnificationFilter = .neareston a
UIImageView. Under SwiftUI you call
myImage.interpolation(.none). The iOS LifeHash library already does this for you.
- The iOS/Mac LifeHash library renders LifeHash images asynchronously and caches the result, so if you pass in the same Fingerprint you'll get the same image back right away. But if LifeHash rendering seems slow, be sure you're compiling the Release configuration of your target: LifeHash is really fast when compiled for Release.
LifeHash is available under the BSD-2-Clause license. See LICENSE.md for more info.
LifeHash is a project of Blockchain Commons. We are proudly a "not-for-profit" social benefit corporation committed to open source & open development. Our work is funded entirely by donations and collaborative partnerships with people like you. Every contribution will be spent on building open tools, technologies, and techniques that sustain and advance blockchain and internet security infrastructure and promote an open web.
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The following people directly contributed to this repository. You can add your name here by getting involved — the first step is to learn how to contribute from our CONTRIBUTING.md documentation.
|Wolf McNally||Originator, Project Lead||@WolfMcNally||<Wolf@WolfMcNally.com>||9436 52EE 3844 1760 C3DC 3536 4B6C 2FCF 8947 80AE|
|Christopher Allen||Principal Architect||@ChristopherA||<ChristopherA@LifeWithAlacrity.com>||FDFE 14A5 4ECB 30FC 5D22 74EF F8D3 6C91 3574 05ED|
We want to keep all our software safe for everyone. If you have discovered a security vulnerability, we appreciate your help in disclosing it to us in a responsible manner. We are unfortunately not able to offer bug bounties at this time.
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Reporting a Vulnerability
Please report suspected security vulnerabilities in private via email to ChristopherA@BlockchainCommons.com (do not use this email for support). Please do NOT create publicly viewable issues for suspected security vulnerabilities.
The following keys may be used to communicate sensitive information to developers:
|Christopher Allen||FDFE 14A5 4ECB 30FC 5D22 74EF F8D3 6C91 3574 05ED|
You can import a key by running the following command with that individual’s fingerprint:
gpg --recv-keys "<fingerprint>" Ensure that you put quotes around fingerprints that contain spaces.