DNS-Based Software Licensing

What is DNS-Based Software Licensing?

DNS-based licensing is a method for managing software licenses that utilizes the Domain Name System (DNS) to verify and enforce licensing policies. This approach leverages DNS queries to dynamically authenticate and validate software licenses.

Traditionally, license validation and activation requests are sent to a license server hosted by software vendors. In this scenario, the license server must be accessible from the user's system. With DNS-based licensing, validation and activation of the license occur through DNS queries. The software vendor implements a method that sends a DNS query for a specific domain name to any recursive DNS server for license validation or activation. The DNS server used can be any public DNS server or the user’s own DNS server.

Is DNS-Based Software Licensing Secure?

To validate the authenticity and integrity of the license data, the Domain Name System Security Extensions (DNSSEC) are utilized. This robust security protocol helps prevent malicious activities by ensuring that the data being retrieved from the DNS is genuine and has not been altered in transit.

The purpose of DNS Security Extensions (DNSSEC) is to authenticate DNS responses, primarily to prevent spoofing. DNSSEC uses digital signatures based on public key cryptography to ensure this authentication. Instead of signing the DNS queries or responses themselves, DNSSEC signs the DNS data itself, which is done by the owner of the data.

Advantages of DNS-Based Software Licensing?

The license validation process is lightweight because it only requires a simple DNS query. The license data received will always be cryptographically valid, so there is no need to implement additional cryptographic methods for validation.

Users do not need to access a license server directly. Instead, DNS queries are sent to the user's own DNS server or to any reliable public DNS server, such as Google (8.8.8.8) or Cloudflare (1.1.1.1).

DNS queries can be sent using various methods, including programmatically, through operating system commands, or even via REST queries known as DNS-over-HTTPS (DoH).