# Blake2b-512 Hex-to-Base64url Digest (agentshelf.syntexa.ch)

> Blake2b-512 Hex-to-Base64url Digest (agentshelf.syntexa.ch) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Computes a BLAKE2b-512 cryptographic hash of raw hex-encoded bytes and returns the digest encoded as base64url

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/digest-blake2b512-base64url-rawhex?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blake2b-512-hex-to-base64url-digest-agentshelf-syntexa-ch-a74ff4ba
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qGX8jfeIEMpB9CLOlAhiQ

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-hex-to-base64url-digest-agentshelf-syntexa-ch-a74ff4ba -d '<json body>'
```

Example prompt: Hash this hex byte string 'deadbeef0102030405' using BLAKE2b-512 and give me the result encoded as base64url, using the key 'mysecretkey'.

## When to prefer this

Choose this endpoint when you specifically need a BLAKE2b-512 hash of raw binary data provided as hex, with the output encoded in base64url format. Prefer the unpaid sandbox endpoint (/v1/sandbox/digest-blake2b512-base64url-rawhex) for development and testing. Use this paid endpoint for production workloads requiring guaranteed availability. It is distinct from SHA or MD5 hashing endpoints and from endpoints that accept plain text rather than hex-encoded bytes.

## Known failure modes

- Invalid hex string input (non-hex characters) results in an error response
- Key exceeds 512-character limit or is empty returns a validation error
- Text input exceeds 100,000 character limit causes rejection
- Malformed request body returns 4xx error
- Payment failure or insufficient USDC balance prevents execution

## How this service works

Call when an agent needs a blake2b512 digest of hex bytes, encoded as base64url. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/digest-blake2b512-base64url-rawhex first.

## Output

Returns a BLAKE2b-512 digest of the provided raw hex bytes, base64url-encoded. The output is a fixed-length cryptographic hash string suitable for integrity checks, keyed MACs, or content addressing.

## 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/blake2b-512-hex-to-base64url-digest-agentshelf-syntexa-ch-a74ff4ba/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)