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HMAC-SHA224 Base64 Signing
x402
HMAC-SHA224 Base64 Signing is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).
Computes an HMAC-SHA224 message authentication code over a given text using a caller-supplied key and returns the result encoded as base64.
Price / call$0.001
Success—
StatusUnknown
How this service works
Call when an agent needs an HMAC-sha224 of text with a caller-supplied key, encoded as base64. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha224-base64 first.
Output
A JSON response containing the base64-encoded HMAC-SHA224 digest of the input text, computed using the provided secret key. The output is a deterministic, fixed-length string suitable for use in authentication headers, integrity checks, or storage alongside records.
Example use cases
Webhook signature verification
“I need to sign the webhook payload '{"event":"order.completed","id":"abc123"}' using HMAC-SHA224 with the key 'wh_secret_xyz' and get the base64 result so I can include it in my signature header.”
API request authentication
“Generate an HMAC-SHA224 base64 signature for the string 'GET/v2/users1700000000' using the key 'api_secret_456' — I need to attach it as an auth token to my outgoing API request.”
Data integrity tagging
“Compute the HMAC-SHA224 of the text 'invoice-2024-09-01:$4200.00:client-789' with key 'ledger_key_001' and return it as base64 so I can store it alongside the record as a tamper-evident tag.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/hmac-sha224-base64?utm_source=zero.xyzWhen to prefer
Prefer this endpoint when you specifically need HMAC-SHA224 (not SHA256 or SHA512) with base64 output encoding and a caller-supplied key. It is a pure computational endpoint with no side effects, making it safe to call repeatedly. Use the free sandbox endpoint POST /v1/sandbox/hmac-sha224-base64 for testing before incurring the $0.001 USDC charge on this paid endpoint.
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 (insufficient USDC balance) results in a 402 response
- Network timeout if the service is temporarily unavailable
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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