Function signMAC

internal/approvaltoken/token.go:154–158

(secret, payload []byte)

}

func signMAC(secret, payload []byte) []byte {
	mac := hmac.New(sha256.New, secret)
	mac.Write(payload)
	return mac.Sum(nil)
}

// PeekMessageID extracts the message_id from a token *without* verifying
// the HMAC. Useful when the caller needs to look up the owning user's