Rent Collection for Blockchain Data

EIPS/eip-755.md

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+---
+eip: 755
+title: Rent Collection for Blockchain Data
+author: Daniel A. Nagy <daniel@ethereum.org>, Zsolt Felfoldi <zsolt@ethereum.org>
+discussions-to: 
+status: Draft
+type: Standards Track
+category: Core
+created: 2017-11-01
+---
+
+## Simple Summary
+Introducing a way to collect rent from accounts that is proportional 
+to the cost that they impose on the network by storing a large state
+over a long period of time.
+
+## Abstract
+A new global parameter called `rent` similar to `gasLimit` that can be 
+modified by miner vote is introduced. It is initialized at 0 and is 
+assumed to have been zero before its introduction. The miner validating 
+a particular block can increase rent in a bounded way at the cost of 
+forfeiting a proportional part of the mining reward. Similarly, if 
+`rent` is more than zero, one can decrease it in a bounded way and 
+receive the same additional mining reward that would need to be 
+forfeited to raise it back.
+
+With each new block, an account is chosen in a deterministically random 
+fashion with a probability proportional to the amount of storage that 
+they use. The current value of `rent` is subtracted from their balance 
+and if the result is negative, the account gets removed from the state. 
+Otherwise, account balance is updated by the result.
+
+## Motivation
+Currently, contracts storing a large state over a long period of time 
+impose considerable cost on the network and do so for free, having 
+insufficient incentives to keep their state small. This results in
+an unreasonable waste of a scarce resource.
+
+## Specification
+### TODO
+Both `rent` is available as readable environment to contracts.
+
+## Rationale
+The proposed rent control mechanism creates a *tragedy of commons* type 
+coordination problem between miners, privatizing the costs of raising 
+`rent` while the benefit is common and, conversely, privatizing the 
+benefit of reducing `rent` while the cost is socialized. It is up to 
+miners to coordinate through smart contracts; it is not part of the protocol.
+In general, this bias towards reducing the rent is intended to keep 
+rent in check and make it difficult for miners to raise rent beyond 
+the actual cost of storing the state.
+
+## Backwards Compatibility
+The fact that both `rent` is initialized as zero and assumed to have been 
+zero before introducing the protocol change, the entire history of the 
+blockchain is conforming to the rules introduces in this protocol change. 
+Since miners are beneficiaries of the change, no difficulty is expected 
+with acceptance by miners.
+
+## Test Cases
+### TODO
+
+## Implementation
+### TODO
+
+## Copyright
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).