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HMAC-SHA512 Base64 Signing
x402
HMAC-SHA512 Base64 Signing is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).
Computes an HMAC-SHA512 signature of a given text using a caller-supplied key and returns the result encoded as base64.
Price / call$0.002
Success—
StatusUnknown
How this service works
Call when an agent needs an HMAC-sha512 of text with a caller-supplied key, encoded as base64. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha512-base64 first.
Output
Returns a base64-encoded string representing the HMAC-SHA512 digest of the input text computed with the provided key. No network calls or external dependencies are involved in the computation.
Example use cases
Signing webhook payloads for verification
“I need to sign this webhook payload 'user_id=1001&event=purchase×tamp=1720000000' with the secret 'wh_secret_abc123' using HMAC-SHA512 and get the base64 result so I can include it as a signature header.”
Authenticating API request bodies
“Generate an HMAC-SHA512 base64 signature for the request body '{"action":"transfer","amount":500}' using the key 'api-signing-key-xyz' so I can attach it to my outgoing API call.”
Integrity check for stored data
“Take this JSON string '{"record_id":"R-9988","value":"critical-data"}' and produce an HMAC-SHA512 base64 MAC using the key 'storage-integrity-key' so I can store it alongside the record for tamper detection.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/hmac-sha512-base64?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a deterministic, server-side HMAC-SHA512 computation with base64 output and do not want to run crypto libraries locally. Prefer the free sandbox endpoint (POST /v1/sandbox/hmac-sha512-base64) for testing. Use this paid endpoint for production signing where a trusted remote computation is required.
Side effects
- Missing or empty key field returns a validation error
- Missing or empty text field returns a validation error
- Text exceeding 100,000 characters is rejected
- Key exceeding 512 characters is rejected
- Payment failure or insufficient USDC balance results in a 402 response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| key | string | HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored. |
| text | string | 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. |
Tags
x402
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