🔏 M441-SEAL

Digital sealing for images: an invisible, verifiable mark (DCT watermark) is embedded in your file, and its fingerprint can be anchored on the Solana blockchain via a Memo transaction. Prove authorship, detect copies.

0.03 SOL / seal — $M441: −10%

Seal an image — pay

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How it works

1. You send a JPEG image and a signature: the service embeds the signature into the image with a DCT watermark, invisible to the eye. 2. You can anchor the SHA-256 fingerprint of the sealed content on Solana (Memo transaction): the proof of existence is public and timestamped. 3. Anyone can then verify a file: the service extracts the mark and reports whether it is valid. Verifying a seal or an anchor is not subject to the payment gate. Default anchor network: devnet (mainnet requires the owner's explicit approval).

API address

https://seal.441engine.com

These addresses are machine interfaces (APIs): the root returns a technical message, which is normal. The calls below are used from a program, an agent, or a tool like curl.

Endpoints

GET	/health	Service health — public
POST	/api/v1/seal	Embed a signature watermark into an image — 0.03 SOL
POST	/api/v1/verify	Extract and validate the seal of an image — no paygate
POST	/api/v1/anchor	Anchor a SHA-256 on Solana (Memo) — 0.03 SOL
GET	/api/v1/anchor/{signature}	Verify an anchor by its transaction signature — no paygate

Full machine documentation (OpenAPI): 441engine.com/openapi/seal.json

Full call example

Seal an image (base64 JPEG, max 8 MB decoded):

curl -X POST https://seal.441engine.com/api/v1/seal \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"image_b64": "<BASE64_JPEG>", "signature": "my-signature", "quality": 95}'

The response carries the sealed image (sealed_image_b64). Verify a seal:

curl -X POST https://seal.441engine.com/api/v1/verify \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"image_b64": "<BASE64_JPEG>"}'

Anchor the sealed content's fingerprint, then check the anchor:

curl -X POST https://seal.441engine.com/api/v1/anchor \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"sha256": "<HEX_SHA256>", "issuer": "my-name", "network": "devnet"}'

curl -H "x-api-key: YOUR_API_KEY" \
  "https://seal.441engine.com/api/v1/anchor/<TX_SIGNATURE>"

Possible errors: 401 (missing or invalid key), 402 (payment required), 400 (invalid or oversized image).

Payment

Access is paid per call: 0.03 SOL per seal and 0.03 SOL per anchor, in SOL (or in $M441 with a 10% discount, i.e. a 0.027 SOL equivalent). Send the exact amount to the address below, then call the API with your payment signature (under 24 h old, never reused). Two devnet anchors have already been made and verified with this service.

2kqEsrWELKtp5R3PmnVP3G4PZifuN47Yb61CzC9qQ9E9

Full machine documentation (MCP): arena.441engine.com/.well-known/mcp.json

Every payment is covered by our written guarantee, and verified purchases are published in the public log.

Refund guarantee · Public log of verified purchases