tagdrop

about

description

TagDrop turns small files — text, HTML pages, images, audio, SVGs — into self-contained QR codes that work completely offline. Print one on a sticker or sheet of paper and leave it somewhere; anyone with the TagDrop app (or any QR scanner that follows tagdrop: links) can scan it and view the content immediately, with no internet connection, server, or account required. Think of it as a digital geocache: instead of a logbook in a box, the "cache" is the QR code itself. <b>What you can do with it</b> <ul> <li>Drop a single page — encode text, an HTML page, an SVG image, or JSON into one QR code, either in-app (Create Cache) or with the web generator.</li> <li>Drop a whole "paper" — a printable sheet with a directory QR code (a paper manifest) plus one QR per file, built in-app (Create Paper) or with the web generator. Pages can link to each other with ordinary relative links, so a small static site survives being printed and scanned back in.</li> <li>Spread large content across multiple codes — split a payload too big for one QR into multiple sector codes placed along a trail. The app collects sectors in any order, reassembles and verifies them, and can recover a single missing sector from an optional parity code.</li> <li>Build trails, collections, and replies — link papers together with location hints, tag a loose set of stickers with a shared collection so they group into one card on the home screen and map, or mark a code as a reply to another to thread a conversation across drops.</li> <li>Browse offline — scanned pages render in an in-app viewer, with search and #hashtag filtering, and a hex/CBOR inspector for the curious. The Collections, History, and Map tabs let you revisit, locate, and manage everything you've found, and a single file can back up or restore it all.</li> <li>Tap instead of scan — write any TagDrop code to a blank or rewritable NFC tag, then read it back with a tap instead of the camera.</li> <li>Sign your drops — post-quantum (ML-DSA-44) Verified Authorship signing lets anyone who scans your codes recognise them as genuinely yours after the first scan (trust-on-first-use), with a ✅/⚠️/🔏 badge shown on every signed item. Back up your signing identity to a passphrase-protected file to keep the same recognisable signer across devices.</li> </ul> <b>How it works</b> Every code carries a tagdrop: URI — a QDEF container of CBOR Records, Base41-encoded so it packs efficiently into a QR code's alphanumeric mode. Content can optionally be DEFLATE-compressed and split across multiple codes with parity recovery. IDs are content-addressed (SHA-256 based), so identical content always gets the same ID regardless of who created it. The full wire-format spec is browsable in-app, no internet connection required. <b>Status</b> V2.5 — QDEF-based wire container encoding with content split into codes plus optional parity recovery, post-quantum (ML-DSA-44) content signing with trust-on-first-use verification, paper manifests with multi-file directories and relative-link navigation, geographic trails via "related" hints, ad-hoc collections, reply threading, an in-app scanner with a live scan board, NFC tag read/write, search and #hashtag filtering, full backup/restore, a Map tab for located finds, and remote drop-source feeds that pre-populate the map with community drops before you scan them.

publisher

78ce6faa72264387284e647ba6938995735ec8c7d5c5a65737e55130f026307d

first seen

2026-10-08T20:20:58.290716+00:00

last event

2026-08-10 01:22 UTC

install

zapstore.dev or any Zapstore-compatible client

source & build

repository

https://github.com/mofosyne/tagdrop

arch flags

android-arm64-v8a

manifest

missing

releases (kind 30063)

1 release indexed; latest 2.6.2.

assets & verification

Every app, release and asset event is schnorr-verified (NIP-01 id + signature) before it enters the catalog, and assets are content-addressed by sha256. We subscribe read-only to the catalog relay — never write to it.

2.6.2 — com.github.mofosyne.tagdrop_14.apk

sha256

014590dd5e148d511dba592cd4ba47b536adbd0356ba42cdbb67fb8981474b9d

size

10.1 MB

archs

android-arm64-v8a

version code

14

apk cert sha256

f92099033c52b7b8266928947fc0da8d0a88fd59f68e72f07f9107df316f4456

download

com.github.mofosyne.tagdrop_14.apk

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