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HMAC-SHA384 Base64 Signer
x402
HMAC-SHA384 Base64 Signer is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-09-29).
Computes an HMAC-SHA384 signature of input text using a caller-supplied key and returns it encoded as Base64.
Price / call$0.009
Success—
StatusUnknown
How this service works
Call when an agent needs an HMAC-sha384 of text with a caller-supplied key, encoded as base64. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha384-base64 first.
Output
Returns a Base64-encoded string containing the HMAC-SHA384 digest of the input text computed with the provided secret key. This is a fixed-length, deterministic authentication code that can be used for message integrity verification or authentication.
Example use cases
Signing webhook payloads securely
“I need to sign the webhook body '{"event":"order.created","id":"ord_789"}' with the secret key 'whsec_abc123XYZ' using HMAC-SHA384 and get the Base64 digest so I can include it in the webhook signature header.”
Authenticating API request integrity
“Before sending this API request body 'user_id=42&action=transfer&amount=500' to our payment service, sign it with the key 'api-signing-key-prod-2024' using HMAC-SHA384 Base64 so the server can verify it wasn't tampered with.”
Generating checksum for file content
“Take the text content of this config file — 'host=db.internal\nport=5432\npassword=secret' — and compute an HMAC-SHA384 Base64 signature using the key 'config-integrity-key' so I can store it alongside the file to detect future changes.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/hmac-sha384-base64?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need HMAC-SHA384 specifically (stronger than SHA256) and want the output as Base64. If cost is a concern, try the free sandbox endpoint at /v1/sandbox/hmac-sha384-base64 first. Prefer this paid endpoint for production use or when the sandbox is unavailable.
Side effects
- Empty or missing key (minLength:1 violated) returns validation error
- Text exceeds 100,000 character limit returns 413 or validation error
- Missing required fields returns 400 bad request
- Payment of $0.009 USDC not provided or declined returns 402 Payment Required
- Malformed JSON body returns 400
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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