# agentshelf.syntexa.ch BLAKE2b-512 Digest of Hex Bytes (Base64)

> agentshelf.syntexa.ch BLAKE2b-512 Digest of Hex Bytes (Base64) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.008/call, status unknown (last checked 2026-10-02).

Computes a BLAKE2b-512 cryptographic hash of raw bytes supplied as a hex-encoded string, returning the digest encoded as standard Base64.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/digest-blake2b512-base64-rawhex?utm_source=zero.xyz
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-blake2b-512-digest-of-hex-bytes-base64-807d7d2c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3D3MlLCLC8GUyPYM9SfYh

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 agentshelf-syntexa-ch-blake2b-512-digest-of-hex-bytes-base64-807d7d2c -d '<json body>'
```

Example prompt: Can you compute the BLAKE2b-512 hash of this hex string — 'deadbeef0102030405' — and give me the result as Base64?

## When to prefer this

Choose this endpoint when your input data is already represented as a hex-encoded byte string (e.g. raw binary frames, file chunks, protocol payloads) and you need a BLAKE2b-512 digest in standard Base64 format. Use the sibling text-input endpoints instead if your input is plain UTF-8 text rather than hex bytes. Prefer the sandbox (unpaid) version for testing before committing to the $0.008 USDC cost.

## Known failure modes

- Invalid hex string (odd length or non-hex characters) causes a 400 error
- Input text exceeds 100,000 character limit returns a payload-too-large error
- Key exceeds 512-character limit returns a validation error
- Malformed JSON body returns a 400 bad request
- Insufficient USDC balance or payment failure returns a 402 Payment Required

## How this service works

Call when an agent needs a blake2b512 digest of hex bytes, encoded as base64. Exact $0.008 USDC. Prefer unpaid POST /v1/sandbox/digest-blake2b512-base64-rawhex first.

## Output

Returns a Base64-encoded string representing the 512-bit BLAKE2b digest of the raw bytes decoded from the input hex string. If a key is provided, the digest is computed as a keyed BLAKE2b-512 MAC.

## 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": [
    "68656c6c6f"
   ],
   "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/agentshelf-syntexa-ch-blake2b-512-digest-of-hex-bytes-base64-807d7d2c/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)