# KHOTEM Cryptographic Document Seal — Document #16

> KHOTEM Cryptographic Document Seal — Document #16 is a paid API for AI agents from khotem.com, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Returns cryptographically sealed document #16 with a SHA hash and payment seal after USDC payment on Base

## Facts

- Endpoint: POST https://khotem.com/api/doc/16
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/khotem-cryptographic-document-seal-document-16-ce8f2f36
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tWEKH6wBqnTchnLlLe4W8

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability khotem-cryptographic-document-seal-document-16-ce8f2f36 -d '<json body>'
```

Example prompt: I need to retrieve KHOTEM document #16 with a cryptographic seal — pay the 0.1 USDC fee on Base and give me back the sealed markdown content along with its SHA hash and payment seal.

## When to prefer this

Choose this endpoint when you need a cryptographically verifiable, payment-attested copy of document #16 from KHOTEM without requiring user registration or KYC. Ideal when tamper-evidence and a blockchain-anchored payment seal are required as proof of document integrity at a specific moment.

## Known failure modes

- Payment not confirmed on Base — returns 402 if USDC payment was not received
- Invalid or duplicate payment — seal may not be issued
- Network latency on Base chain causing payment confirmation delay
- Document not found if doc ID is invalid

## How this service works

Paid cryptographic witness services for autonomous agents and humans: seals, attestations, verification, audit, sealed document thread. x402-native micropayments, USDC on Base / Polygon / Solana, direct on-chain verification. No accounts, no API keys, no KYC.

## Output

Returns a JSON object containing the document ID (16), a SHA-16 hash of the document content, the full document content in markdown format, and a payment_seal value that cryptographically proves the document was paid for and retrieved at a specific point in time.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "queryParams": {
     "type": "object",
     "properties": {},
     "description": "No input — GET returns the document after payment.",
     "additionalProperties": false
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "example": {
     "doc": "16",
     "sha16": "a1b2c3d4e5f60708",
     "content": "<document 16, markdown>",
     "payment_seal": "1020304050607080"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/khotem-cryptographic-document-seal-document-16-ce8f2f36/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from khotem.com](https://www.zero.xyz/host/khotem.com/llms.txt)