RedistributedDemurrageToken

Ownership

• Contract creator is owner
• Ownership can be transferred (also to ownership void contract)

Mint

• Owner can add minters
  • A faucet contract would be a minter
• Minters can mint any amount

Demurrage

• Decay amount (ppm) and period (blocks) is set at deploy time.
  • Cannot be changed
• Tax is applied when a mint or transfer is triggered for first time in new period;
  • Supply stays the same.
  • Updates demurrageModiifer which represents an exponential decay step.
• All client-facing values (balance output , transfer inputs) are adjusted with demurrageModifier.
• Edge case: approve call, which may be called on either side of a period.

Redistribution

• One redistribution entry is added to storage for each period;
  • When mint is triggered, the new totalsupply is stored to the entry
  • When transfer is triggered, and the account did not yet participate in the period, the entry's participant count is incremented.
• Account must have "participated" in a period to be redistribution beneficiary.
• Redistribution is applied when an account triggers a transfer for the first time in a new period;
  • Check if have participated in period.
  • Balance is increased by (total supply at end of period * demurrage modifier ) / number of participants
  • Participation field is zeroed out.
• Fractions must be rounded down (TODO)
  • Remainder is "dust" and should be sent to a dedicated "sink" address (TODO)

Data structures

• One word per account:
  • bits 000-159: value
  • bits 160-255: period
  • (we have more room here in case we want to cram something else in)
• One word per redistribution period:
  • bits 000-055: period
  • bits 056-215: supply
  • bits 216-253: participant count
  • bits 254: Set if invidiual redistribution amounts are fractions (TODO)
  • bits 255: Set if "dust" has been transferred to sink (TODO)

QA

• Basic python tests in place
• How to determine and generate test vectors, and how to adapt them to scripts.
• Audit sources?