[bitcoin-dev] idea post: trimming and demurrage

Tue Sep 26 07:10:43 UTC 2017

Lets call it blocktrain instead of blockchain. Because it is fixed amount
of blocks moving forward on the time axis. Oldest blocks are detached from
the tail of that blockTrain and goes to depot.

2017-09-26 4:33 GMT+03:00 Patrick Sharp via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org>:

> Thank you for your responses. I have been enlightened. For the time being
> the combination of the UTXO's and pruning will accomplish what I desire. I
> suspect that there will come a time when the UTXO database becomes too
> large, but I guess that is a problem for another day. If that day ever
> comes 10 years was just an example, like you said there are reasons to
> preserve value beyond that point, perhaps a human lifetime or two would be
> a better choice.
>
> Side question: wouldn't it be a good idea to store the hash of the current
> or previous UTXO's in the block header so that pruned nodes can verify
> their UTXO's are accurate without having to check the full chain? and/or
> maybe include a snap shot of the UTXO's every x blocks?
>
> You guys are totally awesome!!!
>
> I here by withdraw my proposal for the time being.
>
> On Mon, Sep 25, 2017 at 5:34 PM, ZmnSCPxj <ZmnSCPxj at protonmail.com> wrote:
>
>> Good morning Patrick,
>>
>> Demurrage is simply impossible.
>>
>> In Bitcoin we already have implemented OP_CHECKLOCKTIMEVERIFY.
>>
>> This opcode requires that a certain block height or date has passed
>> before the output can be spent.
>>
>> It can be used to make an "in trust for" address, where you disallow
>> spending of that address.  For example, you may have a child to whom you
>> wish to dedicate some inheritance to, and ensure that the child will not
>> spend it recklessly until they achieve some age (when hopefully they would
>> be more mature), regardless of what happens to you.
>>
>> If I made a P2SH address with OP_CHECKLOCKTIMEVERIFY that allows spending
>> 18 years from birth of my child, and then suddenly Bitcoin Core announces
>> demurrage, I would be very angry.
>>
>> OP_CHECKLOCKTIMEVERIFY cannot be countermanded, and it would be
>> impossible to refresh the UTXO's as required by demurrage, without
>> requiring a hardfork that ignores OP_CHECKLOCKTIMEVERIFY.
>>
>> It would be better to put such additional features as demurrage in a
>> sidechain rather than on mainchain.
>>
>>
>> Regards,
>> ZmnSCPxj
>>
>> -------- Original Message --------
>> Subject: [bitcoin-dev] idea post: trimming and demurrage
>> Local Time: September 25, 2017 9:54 PM
>> UTC Time: September 25, 2017 9:54 PM
>> From: bitcoin-dev at lists.linuxfoundation.org
>> To: bitcoin-dev at lists.linuxfoundation.org
>>
>> Hello Devs,
>>
>> I am Patrick Sharp. I just graduated with a BS is computer science.
>> Forgive my ignorance.
>>
>> As per bip-0002 I have scoured each bip available on the wiki to see if
>> these ideas have already been formally proposed and now as per bip-0002
>> post these ideas here.
>>
>> First and foremost I acknowledge that these ideas are not original nor
>> new.
>>
>> Trimming and demurrage:
>>
>> I am fully aware that demurrage is a prohibited change. I hereby contest.
>> For the record I am not a miner, I am just aware of the economics that
>> drive the costs of bitcoin.
>>
>> Without the ability to maintain some sort of limit on the maximum length
>> or size of the block chain, block chain is not only unsustainable in the
>> long run but becomes more and more centralized as the block chain becomes
>> more and more unwieldy.
>>
>> Trimming is not a foreign concept. Old block whose transactions are now
>> spent hold no real value. Meaningful trimming is expensive and inhibited by
>> unspent transactions. Old unspent transactions add unnecessary and unfair
>> burden.
>> Old transactions take up real world space that continues incur cost while
>> these transactions they do not continue to contribute to any sort of
>> payment for this cost.
>> One can assume that anybody with access to their bitcoins has the power
>> to move these bitcoins from one address to another (or at least that the
>> software that holds the keys to their coins can do it for them) and it is
>> not unfair to require them to do so at least once every 5 to 10 years.
>> Given the incentive to move it or lose it and software that will do it
>> for them, we can assume that any bitcoin not moved is most likey therefore
>> lost.
>> moving these coins will cost a small transaction fee which is fair as
>> their transactions take up space, they need to contribute
>> most people who use their coins regularly will not even need to worry
>> about this as their coins are moved to a change address anyway.
>> one downside is that paper wallets would then have an expiration date,
>> however I do not think that a paper wallet that needs to be recycled every
>> 5 to 10 years is a terrible idea.
>> Therefore I propose that the block chain length be limited to either 2^18
>> blocks (slightly less than 5 years) or 2^19 blocks, or slightly less than
>> 10 years. I propose that each time a block is mined the the oldest block(s)
>> (no more than two blocks) beyond this limit is trimmed from the chain and
>> that its unspent transactions are allowed to be included in the reward of
>> the mined block.
>>
>> This keeps the block chain from tending towards infinity. This keeps the
>> costs of the miners balanced with the costs of the users.
>>
>> Even though I believe this idea will have some friction, it is applicable
>> to the entire community. It will be hard for some users to give up small
>> benefits that they get at the great cost of miners, however miners run the
>> game and this fair proposal is in in their best interest in two different
>> ways. I would like your thoughts and suggestions. I obviously think this is
>> a freaking awesome idea. I know it is quite controversial but it is the
>> next step in evolution that bitcoin needs to take to ensure immortality.
>>
>> I come to you to ask if this has any chance of acceptance.
>>
>> -Patrick
>>
>
>
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