# HMAC String Signing

> HMAC String Signing is a paid API for AI agents from pyfile-agent.taile3ff35.ts.net:10000, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Computes an HMAC (Hash-based Message Authentication Code) of an input string using a specified algorithm and secret key

## Facts

- Endpoint: GET https://pyfile-agent.taile3ff35.ts.net:10000/data/hmac
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hmac-string-signing-7196f93b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_n6Zm-nX_4qrr-TCfviyy4

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 hmac-string-signing-7196f93b
```

Example prompt: Can you compute the HMAC-SHA256 of the string 'hello world' using the secret key 'mysecretkey'?

## When to prefer this

Use this endpoint when you need a quick, stateless HMAC computation without setting up a local cryptography library — especially useful in agent workflows where you need to sign payloads, authenticate API requests, or verify message integrity on the fly using SHA256 or similar algorithms.

## Known failure modes

- Missing required 'input' parameter returns an error
- Unsupported algorithm value returns an error
- Empty or missing key may result in an error or weakened HMAC
- Invalid or malformed query parameters return a 400-style error
- Network or server unavailability returns a 5xx error

## How this service works

HMAC a string. ?algo=sha256&key=k&input=hello

## Output

Returns the HMAC digest of the input string computed with the specified algorithm (e.g. sha256) and secret key, typically as a hex-encoded string representing the cryptographic signature.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "key": {
       "type": "string"
      },
      "algo": {
       "type": "string"
      },
      "input": {
       "type": "string"
      }
     }
    }
   }
  },
  "output": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hmac-string-signing-7196f93b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pyfile-agent.taile3ff35.ts.net:10000](https://www.zero.xyz/host/pyfile-agent.taile3ff35.ts.net%3A10000/llms.txt)