IC Transaction Scanner

Security minded people prefer an air-gapped (AG) setup where they can always keep their private keys offline.

1. Create a transaction on AG computer (e.g. dfx canister sign DFINITY SDK) as a JSON file.
2. Create a QR-Code by cat message.json|gzip -c|base64|qrencode -o message.png.
3. Scan the QR-Code on a non-AG computer (e.g. mobile phone) using this single page app to send it.

This app has been deployed on the IC at https://p5deo-6aaaa-aaaab-aaaxq-cai.raw.ic0.app

Features:

• Send both query and update calls produced by dfx.
• Send update calls with request status produced by quill.
• Support request status for dfx >= 0.7.1.
• Decode message send result in Candid format.
• Reproducible build.
• Switch between text input and camera video.
• Support Add to Home screen from mobile browser.
• Allow input to be passed as a parameter ?msg=... through URL.
• Accept input in 3 formats: JSON text, base64 encoded text, gzipped then base64 encoded text.
• Pick a better default camera (micro-lens) by default, or let user choose.

Note:

• A message has to fit in the QR-Code size limit, which is about 4000 characters. So doing gzip -c|base64 is recommended.
• Blurry image does not work, but you can always enlarge the QR code displayed on your AG computer to help with the scanning.
• The JSON output from quill may be a list of messages, you can extract them one by one using jq to produce multiple QR codes, or use this script to help.

Reproducible build:

You can verify the build by comparing hashes from 3 sources, github release, local build, and the deployed canister:

$ curl -Ls https://github.com/ninegua/ic-qr-scanner/releases/download/v0.1.16/ic-qr-scanner.wasm|sha256sum
54231d1e59ad726b86c4b473005941ffcf276bdd11857f3ed1e894b4eca7b1b8  -

$ cat $(nix-build ic-qr-scanner.nix 2>/dev/null)/bin/ic-qr-scanner.wasm |sha256sum
54231d1e59ad726b86c4b473005941ffcf276bdd11857f3ed1e894b4eca7b1b8  -

$ make dfx.json && dfx canister --no-wallet --network ic info p5deo-6aaaa-aaaab-aaaxq-cai
Controller: ihamg-4yaaa-aaaab-aaafa-cai
Module hash: 0x54231d1e59ad726b86c4b473005941ffcf276bdd11857f3ed1e894b4eca7b1b8

Acknowledgement:

• Single page deployment on IC using the minimalistic tool epic, courtesy of blynn.
• QR scanning is from zbar.wasm.
• CSS is from Simple.css.

To learn more about developing apps on the Internet Computer, see the following documentation available online:

• Quick Start
• SDK Developer Tools
• Motoko Programming Language Guide
• Motoko Language Quick Reference