Quantum computing exploits the phenomena of the infinitely small: superposition (an object can be in several states at the same time), entanglement (two particles can remain linked at a distance) and interference (reinforces good solutions and eliminates bad ones). These properties, specific to the atomic scale, open the way to radically different computers. Google, IBM, Microsoft, Amazon, but also start-ups such as PsiQuantum, IonQ, Pasqal or Alice & Bob, are investing massively. We’ve never been closer to seeing the genie come out of the lamp.
Classical computers use “binary digits” (bits) which can be either 0 or 1. With a bit, we have two possibilities (0 or 1); with two bits, four (00, 01, 10, 11); with eight bits, 256, etc: the growth is exponential, but the processing remains sequential (one state at a time). The computer explores the possibilities one by one, as if it had to test each path of a maze one after the other to find the exit.
“The potential is immense, especially when coupling quantum and AI!”
The quantum computer works at the scale of atoms: its qubits can be 0, 1, or both at the same time thanks to superposition, which allows it to explore all possibilities simultaneously. The quantum computer can try all paths at once, and thanks to interference, it finds the solution quickly. On the other hand, the technical challenges are enormous: the processor must be maintained at absolute zero (around -273 °C) and the quantum state of the qubits (0 or 1) is extremely fragile and can change with heat, light or even observation.
In 2024, Google presents Willow: with 105 qubits, it performs in less than five minutes a calculation that would take a supercomputer 10 septillion years (10⁴²), thanks to a qubit architecture capable of correcting errors. Microsoft is launching Majorana 1 in 2025, a processor using qubits based on more stable Majorana quasi-particles. In France, Alice & Bob combines the reliability of Microsoft-style qubits with corrective code inspired by Google: their “cat qubits” are less sensitive to bit-flip errors (accidental inversion of state 0 or 1).
The challenge is not only to solve calculations more quickly, but to make calculations possible that are currently inaccessible. In finance, banks are testing quantum computing to improve their market performance. In chemistry and pharmacy, AstraZeneca, Roche and Sanofi are accelerating drug discovery using molecular modeling. The potential is immense, especially by coupling quantum and AI: massive data processing would be accelerated, opening the way to more powerful AI, capable of solving problems beyond the reach of classical machines.
Beware of a major cyber risk!
But the genie of the lamp can pass into the hands of the sorcerer. A quantum computer could break the encryption systems protecting our transactions in just a few minutes. The American Standards Organization (NIST) is developing new quantum-resistant encryption standards. Companies like PQShield are developing post-quantum cryptography solutions to protect computer systems against the quantum threat, which could render three-quarters of current encryption methods obsolete.
The most pressing threat? The “Harvest Now, Decrypt Later” risk: Malicious actors can intercept and store encrypted data today, waiting to decrypt it once quantum power becomes available. Sectors where the lifespan of data is long (banking, health, defense) are the most vulnerable. At the same time, regulatory pressure is intensifying: in the United States, the White House sets 2035 as the post-quantum migration objective for federal agencies. Europe with the NIS2 directive and Asia follow, imposing a “forced” technological transition.
What is the answer? The reactive (“detect and respond”) model gives way to a proactive approach, based on “cryptographic agility”. The challenge: being able to update encryption methods across all networks, without costly system overhaul. To do this, cybersecurity players are developing two types of responses: on the one hand, post-quantum cryptography, which aims to update existing systems; on the other, quantum key distribution (QKD), a new theoretically unbreakable encryption method.
The main pillars of the economy are vulnerable. Financial markets whose transactions rely largely on RSA and ECC encryption are at the forefront. Cryptocurrencies would not be spared. Infrastructure, power grids, communications, transportation, all operate encrypted control systems which, if compromised, would cause immediate disruption.
Investments in quantum cybersecurity are soaring, potential on the stock market for cybersecurity stocks?
The global market could exceed $10 billion by the early 2030s. Players in the sector are increasing their innovations: Palo Alto Networks is positioning itself as a reference platform with its 5th generation firewalls, its PAN-OS 12.1 Orion system and its Cipher Translation functionality (converts classical encryption methods into algorithms resistant to quantum computing), which together offer advanced protection against quantum threats. Fortinet is integrating quantum capabilities into FortiOS, with support for QKD and PQC algorithm stacking. Cisco offers secure routers: 8000 Series Secure Routers, with post-quantum pre-shared keys. Zscaler combines classical and post-quantum encryption at scale, facilitating mass deployment of PQC.
The transition to a world quantum safe creates new leaders, both among cybersecurity specialists and hardware manufacturers and pure players quantum. On the stock market, for equity investors, this change represents a catalyst for growth over several years, where security becomes a strategic priority, accelerating the increase in budgets devoted to cybersecurity (hence a potential on the stock market for cybersecurity stocks, Editor’s note). Quantum computing, between promises and threats, is a major challenge for cybersecurity. The genie is about to come out of the lamp, it remains to be seen who will be able to control him.
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