Banco de Portugal and Banco de Espanha have signed a Memorandum of Understanding to build a joint Post-Quantum Cryptography Cooperation Program, formalising a response to a threat that regulators across the eurozone have been circling for some time: the eventual ability of quantum computers to break the cryptographic foundations underpinning financial infrastructure, including the systems that secure crypto assets.
In a joint statement, the two central banks set out the stakes plainly. "Both central banks consider that the absence of a coordinated migration to quantum-resistant technologies can generate systemic risks, which call for close coordination between financial institutions and supervisory authorities," the statement reads. Banco de Portugal added that such risks are "faced more efficiently through coordinated action."
Three phases, one program
The cooperation program is structured in three phases. The first centres on an exchange of information, best practices and common methodologies between the two institutions. The second, still to be defined in scope, may extend to analysis of shared dependencies, assessment of ecosystem readiness and identification of migration priorities across the financial sector.
The third phase goes further. According to the joint statement, "in the third phase, tests, interoperability assessments and analyses of emerging technologies may be carried out." To advance these later stages, the two central banks plan the "formation of a working group with industry," bringing financial institutions directly into the technical work rather than leaving it to supervisors alone.
A pattern of closer ties
The memorandum was signed on the back of a meeting between financial institutions of Portugal and Spain held between Thursday and Friday, the third such meeting this year aimed at strengthening collaboration between the two central banks. That session also brought together top management from some of the main financial institutions of both countries.
Quantum resilience was not the only item on the agenda. As the joint statement describes it, "in the session, the post-quantum cryptography cooperation program was presented and issues related to the competitiveness of the financial sector were also discussed, as well as the risks and opportunities associated with the latest developments in Artificial Intelligence."
Why it matters for crypto
For an industry whose entire security model rests on public-key cryptography, the migration timeline to quantum-resistant algorithms is not an abstract concern. A coordinated approach between neighbouring central banks, covering everything from shared dependencies to interoperability testing, signals that supervisors in the eurozone are beginning to treat the quantum transition as a financial stability issue rather than a purely technical one. Banco de Portugal and Banco de Espanha have not set a timeline for moving between the three phases, nor named the institutions expected to join the planned industry working group.
