Security · x402 · early usage

Audit DKIM selector records

by api.zfinia.com · discovered, not yet claimed by its owner · updated 2026-10-04

30d calls1

30d payers1

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Audit DKIM selector records. The key length follows from the length of the encoded public key, so a short RSA key is readable from the record itself with no cryptography. Reports a key shorter than a stated minimum; a selector left in testing mode, which asks receivers to treat a failure as unsigned so it cannot contribute to DMARC alignment however correctly it signs; a revoked key, with its consequence; and a key type verifiers do not implement.

Tags: dkim · email authentication · domain trust · key management · developer tooling · bazaar

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-04

Input example from Bazaar metadata

{
  "minimum_key_bits": 2048,
  "records": [
    {
      "record": "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDLiL1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijQIDAQAB",
      "selector": "legacy2019"
    },
    {
      "record": "v=DKIM1; k=rsa; t=y; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB",
      "selector": "rollout2026"
    },
    {
      "record": "v=DKIM1; k=rsa; p=",
      "selector": "retired2024"
    },
    {
      "record": "v=DKIM1; k=rsa; s=tlsa; rotation=90d; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0000000000abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB",
      "selector": "odd"
    }
  ]
}

Output example

{
  "assumptions": [
    "The key length is derived from the length of the encoded public key, so a short key is readable from the record itself without any cryptography. The figure is rounded to the nearest common size.",
    "An empty p tag is the documented way to revoke a key, so it is reported as a revocation with its consequence rather than as a malformed record.",
    "A selector in testing mode is reported because it asks receivers to ignore failures, which means the selector cannot contribute to DMARC alignment however correctly it signs."
  ],
  "complete": true,
  "finding_count": 7,
  "findings": [
    {
      "code": "KEY_SHORTER_THAN_REQUIRED",
      "detail": "Selector legacy2019 publishes an RSA key of about 896 bits and 2048 was required. The length follows from the encoded key, so this is readable from the record without any cryptography.",
      "selector": "legacy2019"
    },
    {
      "code": "KEY_SHORTER_THAN_REQUIRED",
      "detail": "Selector rollout2026 publishes an RSA key of about 1536 bits and 2048 was required. The length follows from the encoded key, so this is readable from the record without any cryptography.",
      "selector": "rollout2026"
    },
    {
      "code": "TESTING_FLAG_SET",
      "detail": "Selector rollout2026 declares t=y, which asks receivers to treat a failure as though the message were unsigned. A selector left in testing mode cannot contribute to DMARC alignment.",
      "selector": "rollout2026"
    }
  ],
  "findings_by_code": {
    "KEY_REVOKED": 1,
    "KEY_SHORTER_THAN_REQUIRED": 3,
    "SERVICE_TYPE_EXCLUDES_EMAIL": 1,
    "TAG_NOT_RECOGNISED": 1,
    "TESTING_FLAG_SET": 1
  },
  "limitations": [
    "The records supplied. Nothing resolves DNS, no signature is verified, and whether the private key is held securely is outside this entirely. Not a security assessment.",
    "valid is true only when every selector parsed, carried a usable key and was not left in testing mode."
  ],
  "limits": {
    "maxFindings": 500,
    "maxHeaderBytes": 131072,
    "maxIncludeTree": 200,
    "maxRecordLength": 4096,
    "maxRecords": 2000,
    "spfLookupLimit": 10,
    "spfVoidLookupLimit": 2
  },
  "minimum_key_bits": 2048,
  "not_examined": [],
  "observed_at": "2026-10-02T00:00:00.000Z",
  "passed": false,
  "request_id": "example-request",
  "selector_count": 4,
  "selectors": [
    {
      "key_bits": 896,
      "key_type": "rsa",
      "revoked": false,
      "selector": "legacy2019",
      "testing": false
    },
    {
      "key_bits": 1536,
      "key_type": "rsa",
      "revoked": false,
      "selector": "rollout2026",
      "testing": true
    },
    {
      "key_bits": null,
      "key_type": "rsa",
      "revoked": true,
      "selector": "retired2024",
      "testing": false
    }
  ],
  "service_id": "dkim_record_audit",
  "service_version": "1.0.0",
  "usable_selector_count": 2,
  "valid": false
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/34023.json for the price and payment options.
Pay. Call GET https://api.zfinia.com/x402/v1/dkim-record-audit. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.18 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 1 calls · 1 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.18	0x25e8245f07d5e4873987293dad666afbe56a9608	60s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x25e8245f07d5e4873987293dad666afbe56a9608",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "180000",
    "amountUsd": 0.18,
    "maxTimeoutSeconds": 60
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl -X POST 'https://api.zfinia.com/x402/v1/dkim-record-audit' -H 'Content-Type: application/json' --data '{"minimum_key_bits":2048,"records":[{"record":"v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDLiL1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijQIDAQAB","selector":"legacy2019"},{"record":"v=DKIM1; k=rsa; t=y; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB","selector":"rollout2026"},{"record":"v=DKIM1; k=rsa; p=","selector":"retired2024"},{"record":"v=DKIM1; k=rsa; s=tlsa; rotation=90d; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0000000000abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB","selector":"odd"}]}'
# -> 402 Payment Required; read PAYMENT-REQUIRED
# retry the identical request with PAYMENT-SIGNATURE

JavaScript

const res = await fetch("https://api.zfinia.com/x402/v1/dkim-record-audit", {
  "method": "POST",
  "headers": {
    "content-type": "application/json"
  },
  "body": "{\"minimum_key_bits\":2048,\"records\":[{\"record\":\"v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDLiL1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijQIDAQAB\",\"selector\":\"legacy2019\"},{\"record\":\"v=DKIM1; k=rsa; t=y; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB\",\"selector\":\"rollout2026\"},{\"record\":\"v=DKIM1; k=rsa; p=\",\"selector\":\"retired2024\"},{\"record\":\"v=DKIM1; k=rsa; s=tlsa; rotation=90d; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0000000000abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB\",\"selector\":\"odd\"}]}"
});
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
import json
res = httpx.request("POST", "https://api.zfinia.com/x402/v1/dkim-record-audit", json=json.loads("{\"minimum_key_bits\":2048,\"records\":[{\"record\":\"v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDLiL1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijQIDAQAB\",\"selector\":\"legacy2019\"},{\"record\":\"v=DKIM1; k=rsa; t=y; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB\",\"selector\":\"rollout2026\"},{\"record\":\"v=DKIM1; k=rsa; p=\",\"selector\":\"retired2024\"},{\"record\":\"v=DKIM1; k=rsa; s=tlsa; rotation=90d; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0000000000abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ12345678QIDAQAB\",\"selector\":\"odd\"}]}"))
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: api.zfinia.com
Endpoint: https://api.zfinia.com/x402/v1/dkim-record-audit
Machine-readable: /resources/34023.json