Pith Number

pith:7VUBPIL2

pith:2019:7VUBPIL2B7AKIHGMLQEZZU2OBC

not attested not anchored not stored refs pending

Typer vs. CAPTCHA: Private information based CAPTCHA to defend against crowdsourcing human cheating

Jianyi Zhang, Xiali Hei, Zhiqiang Wang

arxiv:1904.12542 v1 · 2019-04-29 · cs.CR

Open paper page JSON Open Graph Bundle Merged state Verified badge What is a Pith Number?

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{7VUBPIL2B7AKIHGMLQEZZU2OBC}

Prints a linked badge after your title and injects PDF metadata. Compiles on arXiv. Learn more · Embed verified badge

Record completeness

1 Bitcoin timestamp

2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

✓ Portable graph bundle live · download bundle · merged state

The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Receipt and verification

First computed	2026-05-17T23:47:34.883047Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

fd6817a17a0fc0a41ccc5c099cd34e089e84745923f3efcb786e334642ac8ab7

Aliases

arxiv: 1904.12542 · arxiv_version: 1904.12542v1 · doi: 10.48550/arxiv.1904.12542 · pith_short_12: 7VUBPIL2B7AK · pith_short_16: 7VUBPIL2B7AKIHGM · pith_short_8: 7VUBPIL2

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/7VUBPIL2B7AKIHGMLQEZZU2OBC \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: fd6817a17a0fc0a41ccc5c099cd34e089e84745923f3efcb786e334642ac8ab7

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "1c974d259edf1fc92779f50716d9f1cf53dc1418e296dfd3ccc67f45375359dc",
    "cross_cats_sorted": [],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "cs.CR",
    "submitted_at": "2019-04-29T09:52:29Z",
    "title_canon_sha256": "9fda4a2154ef0037037a17f9fee0aa2bab6d61a2c49ee5741d15886453b62890"
  },
  "schema_version": "1.0",
  "source": {
    "id": "1904.12542",
    "kind": "arxiv",
    "version": 1
  }
}