Every Flashy Gold balance is derived from an append-only ledger where an entry is never updated and never deleted — a mistake is corrected by posting an offsetting entry, the way books have worked since long before computers. It is storage-agnostic by construction, so it can move onto a chain without its rules changing.
The invariants
Balance integrity
A debit below zero is refused; a refused write leaves the balance untouched.
Idempotency
Every movement carries a key; a replay settles once, not twice.
Opaque identity
A natural key — an email, a handle — is refused on the way in.
Tamper-evident
Each entry is hash-chained onto the last; altering one breaks every hash after it.