# SHAKE256 Digest Base64URL Encoder

> SHAKE256 Digest Base64URL Encoder is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.007/call, status unknown (last checked 2026-10-01).

Computes a SHAKE256 hash of input text with an optional key and returns the digest encoded as base64url

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/digest-shake256-base64url?utm_source=zero.xyz
- Price: $0.007/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/shake256-digest-base64url-encoder-f6435695
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4dP-2L4Etd59MRnweQWJR

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 shake256-digest-base64url-encoder-f6435695 -d '<json body>'
```

Example prompt: Hash the text 'Hello, world!' using SHAKE256 and give me the result as a base64url-encoded digest, using key 'mySecretKey'.

## When to prefer this

Choose this endpoint when you need a cryptographically sound SHAKE256 hash with base64url output and no side effects — especially when you want a local-equivalent, deterministic digest without setting up cryptographic libraries. Prefer the free sandbox endpoint (/v1/sandbox/digest-shake256-base64url) for testing; use this paid endpoint in production pipelines where cost is acceptable for guaranteed uptime and service terms.

## Known failure modes

- Missing or empty 'text' field returns a validation error
- Text exceeding 100,000 characters is rejected
- Key exceeding 512 characters is rejected
- Payment of exactly $0.007 USDC must be provided; incorrect payment amount causes a 402 error
- Malformed request body returns a 400 error

## How this service works

Call when an agent needs a shake256 digest of text, encoded as base64url. No network and no LLM. Exact $0.007 USDC. Prefer unpaid POST /v1/sandbox/digest-shake256-base64url first.

## Output

Returns a SHAKE256 digest of the provided text, encoded as a base64url string. The response is deterministic — identical input text and key will always produce the same digest. No network calls or LLM inference are involved in the computation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "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/shake256-digest-base64url-encoder-f6435695/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)