Certificate fetching and caching for AWS SNS message verification.
Downloads the signing certificate from the SigningCertURL, extracts the
RSA public key, and caches it in :persistent_term with a 24-hour TTL.
The cache and HTTP client are replaceable via options.
Summary
Functions
Fetch and decode the public key from a message's SigningCertURL.
Functions
@spec fetch(ExAwsSnsVerifier.t(), map()) :: {:ok, tuple()} | {:error, atom()}
Fetch and decode the public key from a message's SigningCertURL.
Checks cache first (:persistent_term), then validates the URL, downloads
the PEM certificate, extracts the RSA public key, and caches it.