years, the “post quantum era” has been like fusion power: always 10 years in the future.

But now the timeline seems to be closing in.  A recent post by a cryptography engineer and a statement by CloudFlare indicated that cryptography systems could be vulnerable as soon as 2029.

Superwhat?

For those who are unfamiliar, in the classical computing model that we’ve all been using for decades, information is stored as bits that are either 0 or 1, like a row of tidy little light switches. A quantum computer, though, uses qubits, which can be 0, 1, or a weird in-between state called a superposition where it’s effectively both at once until you measure it. On top of that, qubits can be entangled, meaning the state of one instantly relates to another no matter the distance.

No, I don’t completely understand how it all works.  Maybe you took more physics than I did.  But the main point is that it opens up all kinds of different ways to attack problems.  It’s still extremely finicky at the moment.  Scaling up to large numbers of qubits – which is where you can do things that clasiccal computing can’t – has proving challenging.  Don’t expect to buy a quantum computing laptop any time soon.  But scientists are making steady progress.

Why It Matters

One of the big implications for quantum computing is that, with enough qubits, you can factor large numbers effortlessly.  This has huge implications for cryptography.  The mathematics that underlines most of modern computing is based on public key encryption, which is based on prime numbers.

In public key encryption, you take two very large prime numbers (p and q) and multiply them together (to give n).  n here is easy to compute, but extraordinarily hard to reverse.  The world is given n as part of a public key, while p and q are kept secret. Because factoring n back into us is computationally infeasible for sufficiently large values, a user can safely encrypt a message using the public key derived from n, knowing that only someone who secretly knows p or q can efficiently compute the private key and reverse the process. In essence, this is a one-way trapdoor: easy to combine, practically impossible to separate, and that asymmetry is what allows secure communication between strangers.

raindog308

raindog308 is a longtime community LETizen, technical writer, and self-described techno polymath. With deep roots in the *nix world, he has a passion for systems both modern and vintage, ranging from Unix, Perl, Python, and Golang to shell scripting and mainframe-era operating systems like MVS. He’s equally comfortable with relational database systems, having spent years working with Oracle, PostgreSQL, and MySQL.

As an avid user of LowEndBox providers, raindog308 runs an empire of LEBs, from tiny boxes for VPNs, to mid-sized instances for application hosting, and heavyweight servers for data storage and complex databases. He brings both technical rigor and real-world experience to every piece he writes.

Beyond the command line, raindog308 has a life-long love of German Shepherd Dogs, high-quality knives, target shooting, theology, tabletop RPGs, playing guitar, and hiking in deep, quiet forests.

His goal with every article is to help users, from beginners to seasoned sysadmins, get more value, performance, and enjoyment out of their infrastructure.

You can find him daily in the forums at LowEndTalk under the handle @raindog308.