Last week, I posted a link to an article about the breach at Juniper Networks — and said it was bad news.

Today, Wired released an article that describes in great detail how the breach affected Juniper’s network gear. For the layfolks in the room, let me summarize the nature of the breach. Then I’ll point out how this breach was caused, probably intentionally, by the NSA, and how the NSA has, in this case, made us all more vulnerable.

To understand the breach, you need to first have a rudimentary understanding of how a virtual private network, or VPN, works. Anyone who works for a company and connects remotely to their company’s network will have heard the term. A VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users. A VPN creates a “tunnel” through the Internet between two points — usually a laptop and a company firewall. Or the two points may be two firewalls, one at the corporate headquarters, the other at a remote branch. The data that flows through this tunnel is encrypted by the VPN software at one end, then decrypted at the other. Theoretically, while the data is in transit, it’s safe from prying eyes. While the process for encrypting data is generally complex, the idea is quite simple. The software simply runs the data through a set of instructions (known as an algorithm) that scramble it all up like an egg. It does this based upon an encryption key. So long as the other end has the same key, and the same algorithm for encryption, it can basically reverse the steps and unscramble the data.