The curious thing about Lucre is, the basic computing block on which it is built predates every modern use of the currency. The Transition Protectorate developed custom individuals to take on the responsibility of banking and financial instruments. These individuals were notoriously corrupt, except for Designate Tau-Seven-Kappa. They developed physical adaptations to allow for a prodigious memory and reasonable physical toughness, and generally undercut one another whenever possible.
Designate T7K opted not to remain on a home planet where younger, sexier banking experts were constantly trying to corrupt its ledger. Instead it flew out with the Cerdian Generation Fleet. When the Fleet encountered a stray Starlifter there was a violent transfer of custody. A fragment of the captured Starlifter infomorph accessed the mind of T7K and found in it an extensive set of mathematical axioms curating an exact ledger of data stretching back generations. The infomorph fragment guided T7K to a deep-space settlement, where it might have lived in happy banking obscurity were it not for the First Technology Census ordered by the Watchers Council.
Promoters of a return to Isolation Initiatives rejoiced in finding a primarily biologic solution to banking and financial instruments, and happily exchanged large amounts of currency for T7K’s base currency, Lucre.