The SSL library ecosystem needs diversity

The Heartbleed bug was really bad for OpenSSL - it let you ask a server a simple question like "How are you" and then have the server tell you anything it wants (password data, private keys that could be used to decrypt all traffic), and the server would have no idea it was happening.

A lot of people have said that we should ditch OpenSSL because this bug is so bad, and because there are parts of the codebase that are odd, and would usually indicate bad programmers, except that they are found in a library that is deployed everywhere.

Ditching OpenSSL is not going to happen any time soon because it is the standard implementation for any server that has to terminate SSL traffic, and writing good crypto libraries is very difficult. So this is not a promising approach.

However this bug and the subsequent panic (as well as the flood of emails telling me to reset passwords etc) indicate the problem with having every software company in the world rely on the same library. Imagine that there were three different SSL software tools that each had a significant share of the market. A flaw in one could affect, at most, the users of that library. Diversification reduces the value of any one exploit and makes it more difficult to find general attacks against web servers.

This diversity is what makes humans so robust against things like the Spanish Flu, which killed ~100 million people but didn't make a dent on the overall human population. Compare that with the banana, which is susceptible to a virus that could wipe out the entire stock of bananas around the world.

You can see the benefits of diversity in two places. One, even inside the OpenSSL project, users had different versions of the library installed on their servers. This meant that servers that didn't have versions 1.0.1a-f installed (like Twilio) were not vulnerable, which was good.

The second is that servers use different programming languages and different frameworks. This means that the series of Rails CVE's were very bad for Rails deployments but didn't mean anything for anyone else (another good thing).

After Heartbleed I donated $100 to the OpenSSL Foundation, in part because it is really important and in part because it's saved me from having to think about encrypting communication with clients (most of the time) which is really, really neat. I will match that donation to other SSL libraries, under these conditions:

  • The library's source code is available to the public.

  • There is evidence that the code has been used in a production environment to terminate SSL connections.

  • The project has room for more funding.

This is not a very large incentive, but it's at least a step in the right direction; if you want to join my pledge, I'll update the dollar amounts and list your name in this post. A prize of $10 million put a rocket into space; I'm hoping it will help spur diversity in the SSL ecosystem as well.

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