Goodbye to RSA Keys … Finally!

Goodbye to RSA Keys … Finally!

I will start off by saying PKI (Public Key Infrastructure) is flawed, but is the core of security on the Internet. But it is in for a bit of a change over the next few years.

Many organisations are worried about large-scale trust breaches, and where the private keys of companies could be leaked, and cause a large-scale loss of trust on the Internet. Basically, it is the Number 1 serious threat for most medium to large size companies, and would cost large companies 100s of millions of dollars to fix.

And so we have all blindly renewed our digital certificates with 2,048 bit keys, and have been told that 512-bit and 1,024 bit keys are insecure (with some companies performing an en-masse change over). TLS 1.3, too, has kicked RSA off the TLS standard, and will not support the encryption of the session key from the client to be sent back to the server using the public key of the server.

Why? Because a single breach of the private key of the server will allow all the keys to be broken, for virtually every session. The way forward is elliptic curve methods, and it is build into Tor, your bank card, Wi-fi, Blockchain, cryptocurrency wallets, and is the method of choice in IoT security.

Elliptic curve methods have much smaller encryption keys than RSA, and have a considerably lesser overhead in terms of processing, memory and energy consumption. We can thus use elliptic curve to sign for a server and to provide their identity (ECDSA — Elliptic Curve Digital Signature Algorithm):

But RSA has held firm in the digital certificate market, because companies have blindly used them for years, and it just continues. But leading companies like Cloudflare have recently been championed the usage of elliptic curve methods [here]:

And so as RSA’s applications reduce by the day, but two major announcements this week will push the world towards elliptic curve methods. The first is that Let’s Encrypt will be able to sign its own “free” certificates, and the second is the shock news of:

This means, in the longer term, that Let’s Encrypt could force the market to replace their fix on RSA keys with ECDSA keys. The root will be signed by ECDSA keys, and will then be able to generate trusted ECDSA keys for their issued certificates.

So from its root in 1977, it is on the way out:

Conclusions

I say it again … PKI is flawed and the sooner we can move away from PKI and create systems which do not rely on the trust of a few companies, the better. For RSA, it has had a good inning, and has led for over 40 years, but it’s time has come. TLS 1.3 provides an indicator that the key passing methods of TLS 1.2 are not acceptable anymore, and with Let’s Encrypt breaking the monopoly of the large root certificate providers, we should see a major change towards ECDSA.

If you want to know a bit about elliptic curve cryptography, here’s a primer:

Otherwise, come on our wonderful MSc programme and learn more about computer security: