The expiration mechanic is how Swiss Francs work and we believe a necessary tradeoff for decentralized cash issuance to work. Validation can be performed with

The expiration mechanic is how Swiss Francs work and we believe a necessary tradeoff for decentralized cash issuance to work. Validation can be performed with any smartphone. Notes are issued in blocks so technically if you downloaded the 2019 Kong Registry contract you would not need connectivity to validate a note. Purpose built hardware can also be built or existing android based POS systems updated to support kong-like validation. Other anti-counterfeiting techniques have been explored but it the only thing that really matters is securing the root of trust. Technically with Swiss Francs, the notes have no value after their "expiration date", with Kong the escrow contract unlocks and the token can be claimed off the notes but the precedent made us comfortable enough with this tradeoff. Alternative implementation 1) notes are not escrowed and funds can be claimed off the bills immediately - this is effectively how paper wallets, java smart card wallets, and trezors work. This is a gift card instrument not a cash instrument. Alternative implementation 2) funds are locked up into perpetuity - all tokens are eventually lost to breakage. Our back of the envelope expectancy was 10 years for these notes. We wanted the majority to be reclaimable well before their anticipated breakage so we set a claim date relatively soon in the future.