# HMAC-RIPEMD160 Hex Digest

> HMAC-RIPEMD160 Hex Digest is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-19).

Computes an HMAC-RIPEMD160 message authentication code for a given text using a caller-supplied key, returning the result as a lowercase hex string.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/hmac-ripemd160-hex?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hmac-ripemd160-hex-digest-78f5dab3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_B-EHBnPtGJ9F5jbqCnpgs

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-ripemd160-hex-digest-78f5dab3 -d '<json body>'
```

Example prompt: Compute the HMAC-RIPEMD160 of the text 'Hello, world!' using the key 'mysecretkey' and give me the result as a hex string.

## When to prefer this

Choose this endpoint when you specifically need HMAC-RIPEMD160 (not SHA-256 or SHA-512 HMAC variants) as a keyed message authentication code, returned in hexadecimal. It is appropriate for legacy systems, cryptocurrency-adjacent workflows (RIPEMD160 is common in Bitcoin address derivation pipelines), or any protocol that mandates RIPEMD160 as the underlying hash. Prefer the free sandbox endpoint (/v1/sandbox/hmac-ripemd160-hex) for testing before committing to paid calls.

## Known failure modes

- Missing or empty 'key' field returns a validation error
- Missing or empty 'text' field returns a validation error
- Text exceeding 100,000 characters rejected with a payload-too-large error
- Key exceeding 512 characters rejected with a validation error
- Payment failure or insufficient USDC balance results in 402 Payment Required
- Malformed JSON body returns a 400 Bad Request

## How this service works

Call when an agent needs an HMAC-ripemd160 of text with a caller-supplied key, encoded as hex. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/hmac-ripemd160-hex first.

## Output

A JSON response containing the HMAC-RIPEMD160 digest of the supplied text computed with the given key, returned as a lowercase hexadecimal string. No external network calls or LLM inference are involved — it is a pure cryptographic computation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "examples": [
    "secret"
   ],
   "maxLength": 512,
   "minLength": 1,
   "description": "HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."
  },
  "text": {
   "type": "string",
   "examples": [
    "hello"
   ],
   "maxLength": 100000,
   "minLength": 1,
   "description": "Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hmac-ripemd160-hex-digest-78f5dab3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)