Technical proof

The technical proof is the piece of the digital euro design that looks least like traditional banking and most like something a cryptographer specified — because it is.

What it is#

The technical proof — also referred to as the master seed — is the hash of a generated 24-word passphrase. The passphrase is kept secret by the user. The technical proof itself is kept by the user, and it is used to generate Entry-IDs, which the PSP uses in settlement instructions.

If the phrase "24-word passphrase" makes you think of crypto wallet recovery phrases, the resemblance is real at the level of mechanism. It is worth being careful about what that does and does not imply: the digital euro is not a cryptocurrency and does not run on a blockchain. Settlement is centralised on the DESP. A 24-word seed is simply a well-understood way to give a user a secret that only they hold.

Why it exists#

The point is user-held control that does not depend on any single PSP continuing to function.

Because the proof lives with the user rather than only inside their bank's systems, the user retains an independent means of establishing their claim on their digital euro holdings. That is what makes the account portable between institutions rather than captive to one.

Where you meet it in practice#

Two moments matter:

• Onboarding — the user is given the passphrase from which the proof derives.
• Switching — when a user moves their account to another PSP, the technical proof is central to making that move possible while keeping the same account identifier.