cdrop

Overview

cdrop is transport only. It does not verify signatures or certificate chains: it checks the text format and total size, stores the text for a limited time, and returns it over a short link. Receivers must verify the artifact themselves with their own tools.

The scope is derived from the artifact class: cnet, pem or ssh. A scoped token is limited to the scopes listed in its configuration.

Artifact types

Allowed PEM blocks

Allowed SSH types: ssh-rsa, ssh-ed25519, ecdsa-sha2-nistp256/384/521, sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com and their -cert-v01@openssh.com certificate forms; GOST 2012 keys ssh-gost2012-256 and ssh-gost2012-512 (no certificate forms).

Blocked: private keys and private-key containers — RSA PRIVATE KEY (PKCS#1), PRIVATE KEY (PKCS#8), ENCRYPTED PRIVATE KEY, EC PRIVATE KEY, DSA PRIVATE KEY, OPENSSH PRIVATE KEY — as well as arbitrary text. Binary PKCS#12/PFX containers are not accepted. One publication may contain at most 16 blocks or SSH lines and is limited by the total body size.

Publish an artifact

Request body is the artifact text as text/plain; charset=utf-8. The class is recognized from the armor or from the SSH line.

curl -X POST https://lab917.ftp.sh/api/v1/objects \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: text/plain; charset=utf-8" \
  -H "X-CDROP-GRANT: request=3" \
  -H "X-CDROP-TTL: 24h" \
  --data-binary @invite.txt

Response 201 Created:

{
  "id": "7Q2M9K4TABCD",
  "url": "https://lab917.ftp.sh/o/7Q2M9K4TABCD",
  "expires_at": "2026-11-05T12:00:00Z",
  "remaining": 3,
  "sha256": "9f2c...",
  "grant": {
    "kind": "request",
    "url": "https://lab917.ftp.sh/p/cdg_...",
    "remaining": 3,
    "expires_at": "2026-11-05T12:00:00Z"
  }
}

remaining is fixed at publication (1–3, server default 3). sha256 is the digest of the stored text. grant is present only when a grant was requested or the request used a grant token.

A no-token web form with captcha is available at /publish.

Limited publication grants

A publish token may issue a grant: a full link to this same service, for example https://lab917.ftp.sh/p/cdg_.... The link lets the recipient publish the next artifact a limited number of times without a publish token. The full link is embedded into the published artifact itself: as an X-CDROP-GRANT header in cnet armor or PEM, or as a # X-CDROP-GRANT: ... comment in SSH text.

Allowed kinds: request (and other cnet kinds) for cnet, pem for PEM, ssh-key/ssh-cert for SSH. Grants are not tied to cnet. A grant is bound to its parent publication row and disappears with it; it cannot be used for metadata, deletion, the admin panel, or to issue another grant. Expired or exhausted grants return 410 Gone.

The captcha form at /publish has an "issue a grant" checkbox; it uses the server default number of publications (grants.uses).

Fetch an artifact

The HTML page shows the artifact with a copy button, a status line, and a link to the text version. The .txt endpoint returns the exact armored text as text/plain.

• Every successful fetch (HTML or .txt) decrements remaining by one.
• HEAD does not decrement and does not count as a fetch.
• When remaining reaches zero or the TTL expires, both endpoints return 410 Gone.
• An unknown ID returns 404 Not Found.
• Concurrent requests never return more bodies than the remaining count.

Page responses set Cache-Control: no-store, X-Robots-Tag: noindex, Referrer-Policy: no-referrer, and a restrictive Content-Security-Policy.

curl https://lab917.ftp.sh/o/7Q2M9K4TABCD.txt

Metadata

Returns publication metadata without consuming a fetch. Requires the publish token.

curl https://lab917.ftp.sh/api/v1/objects/7Q2M9K4TABCD \
  -H "Authorization: Bearer $TOKEN"

{
  "id": "7Q2M9K4TABCD",
  "kind": "invite",
  "scope": "cnet",
  "size": 1302,
  "sha256": "9f2c...",
  "created_at": "2026-11-04T12:00:00Z",
  "expires_at": "2026-11-05T12:00:00Z",
  "remaining": 2
}

kind is one of invite, request, passport, pem, ssh-key, ssh-cert; scope is cnet, pem or ssh. Expired, exhausted, or deleted objects return 410 Gone; unknown IDs return 404.

Delete an artifact

Requires the publish token. Deletion is immediate but soft: the remaining count is set to zero and the object returns 410 Gone until the cleanup cycle removes the row.

curl -X DELETE https://lab917.ftp.sh/api/v1/objects/7Q2M9K4TABCD \
  -H "Authorization: Bearer $TOKEN"

Utility endpoints

200 ok when the database is reachable, 503 otherwise.

Operational metrics are available only to operators.

This page. The site root lab917 is a separate landing page.

Limits and defaults

Errors

The API returns a compact JSON object:

{"error": "object not found"}

CLI

The cdrop executable reads its configuration from the path given by -config (or CDROP_CONFIG) and the publish token from CDROP_TOKEN (or the publish_token field in the config).

# Publish and print the short URL
cdrop publish -config cdrop.yaml -file invite.txt

# Publish with a terminal QR and a PNG copy
cdrop publish -config cdrop.yaml -file invite.txt -qr -qr-out invite.png

# Fetch the text
cdrop get -config cdrop.yaml 7Q2M9K4TABCD

# Metadata
cdrop status -config cdrop.yaml 7Q2M9K4TABCD

# QR in the console, or as a PNG file
cdrop qr -config cdrop.yaml 7Q2M9K4TABCD
cdrop qr -config cdrop.yaml -out link.png 7Q2M9K4TABCD

In the examples above -qr prints the QR code to the console; -qr-out and -out write a PNG file.

Security notes

• Tokens are never returned in responses or written to logs.
• Artifact bodies are not written to logs.
• Fetches are best-effort: a receiver can save the text, so the 3-fetch limit is not a secrecy guarantee.
• Use HTTPS. A reverse proxy may terminate TLS, but the service should not be exposed over plain HTTP.