Key Management and preparing for the Crypto Apocalypse

Today, keeping sensitive information secure is more critical than ever. Although I’m not overly concerned about the looming threat of quantum computers breaking cryptography, I do worry about our approach to key management, which significantly impacts how we will ultimately migrate to new algorithms if necessary.

Traditional key management systems are often just simple encrypted key-value stores with access controls that release keys to applications. Although this approach has served us well in the past, moving away from bearer tokens to asymmetric key-based authentication and, ultimately, the era of post-quantum cryptography (PQC) demands a different approach.

Why am I concerned about bearer tokens? Well, the idea of a long-lived value that is passed around, allowing anyone who sees the token to impersonate its subject, is inherently risky. While there are ways to mitigate this risk to some extent, most of the time, these tokens are poorly managed or, worse, never changed at all. It’s much easier to protect a key that no one sees than one that many entities see.

The old key-value approach was designed around this paradigm, and although some systems have crude capabilities that work with asymmetric keys, they leave much to be desired. If we want seamless, downtime-free rollover of cryptographic keys across complex systems, we need a model that keeps keys isolated even from the entities that use them. This change will significantly improve key rollover.

This shift will require protocol-level integration into the key management layer, but once it’s done in a reusable way, keys can be changed regularly. A nice side effect of this transition is that these components will provide the integration points allowing us to move to new algorithms in the future.

What does this have to do with PQC? Unlike the shift from DES to AES or RSA to ECC, the post-quantum algorithms available now are substantially larger and slower than their predecessors, meaning the gradual migration from the once state-of-the-art to the new state-of-the-art won’t start until it absolutely has to. Instead, the migration to PQC starts by changing the way we build systems, specifically in how we architect key rollover and the lifecycle of keys. I personally believe the near-term impetus for this change will be the deprecation of bearer tokens.

The importance of seamless and automated rollover of keys is crucial for making systems secure, even if the post-quantum apocalypse never happens.

I also think we will see PQC readiness in credentialing systems. For example, we may see ACME clients support enrolling for PQC certificates simultaneously as they enroll for their ECC certificates, or perhaps support the (more bloated) hybrid certificates.

In conclusion, rethinking our key management approach is increasingly important. So far, I have not seen anyone come to market with what I would call a different approach to key management, and we need one.

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