# BLAKE2b-512 Digest as Base64

> BLAKE2b-512 Digest as Base64 is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-01).

Computes a BLAKE2b-512 cryptographic hash of input text and returns it encoded as Base64, with optional HMAC keying.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/digest-blake2b512-base64?utm_source=zero.xyz
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blake2b-512-digest-as-base64-79bd69fd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lpy5xu7__oatWb0qHimks

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 blake2b-512-digest-as-base64-79bd69fd -d '<json body>'
```

Example prompt: Can you hash the text 'Hello, world!' using BLAKE2b-512 and give me the result as a base64 string?

## When to prefer this

Choose this endpoint when you need a BLAKE2b-512 hash encoded specifically as standard Base64 (not hex, base32, or base64url). It is fully deterministic, requires no network access or LLM, and supports optional keyed HMAC-style digests. Prefer the free sandbox endpoint (/v1/sandbox/digest-blake2b512-base64) for testing; use this paid endpoint for production workloads requiring the stronger BLAKE2b-512 algorithm over MD5, RIPEMD-160, or BLAKE2s-256.

## Known failure modes

- Empty or missing 'text' field returns a validation error
- Key exceeding 512 characters triggers a schema validation rejection
- Text exceeding 100,000 characters is rejected with an input size error
- Payment failure or insufficient USDC balance results in a 402 response
- Malformed JSON body returns a 400 Bad Request

## How this service works

Call when an agent needs a blake2b512 digest of text, encoded as base64. No network and no LLM. Exact $0.006 USDC. Prefer unpaid POST /v1/sandbox/digest-blake2b512-base64 first.

## Output

A JSON response containing the BLAKE2b-512 digest of the submitted text, encoded as a standard Base64 string. No network calls or LLM inference are involved; the result is deterministic and reproducible given the same inputs.

## 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/blake2b-512-digest-as-base64-79bd69fd/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)