[Bitcoin-development] A suggestion for reducing the size of the UTXO database

Bob McElrath bob_bitcoin at mcelrath.org
Sun May 10 14:42:54 UTC 2015

That's a lot of work, a lot of extra utxo's, and a lot of blockchain spam, just
so I can do a convoluted form of arithmetic on my balance.

If a tx contained an explicit miner fee and a change address, but did not
compute the change, letting the network compute it (and therefore merge
transactions spending the same utxo), could one add some form of ring signature
a la Dash to alleviate the worsened privacy implications?

Jeff Garzik [jgarzik at bitpay.com] wrote:
> This has been frequently explored on IRC.
> My general conclusion is "dollar bills" - pick highly common denominations of
> bitcoins.  Aggregate to obtain these denominations, but do not aggregate
> further.
> This permits merge avoidance (privacy++), easy coinjoin where many hide in the
> noise (privacy++), wallet dust de-fragmentation, while avoiding the
> over-aggregation problem where you have consolidated down to one output.
> Thus a wallet would have several consolidation targets.
> Another strategy is simply doubling outputs.  Say you pay 0.1 BTC to
> Starbucks.  Add another 0.1 BTC output to yourself, and a final change output. 
> Who can say which output goes to Starbucks?
> There are many iterations and trade-offs between fragmentation and privacy.

Cheers, Bob McElrath

"The individual has always had to struggle to keep from being overwhelmed by
the tribe.  If you try it, you will be lonely often, and sometimes frightened.
But no price is too high to pay for the privilege of owning yourself." 
    -- Friedrich Nietzsche

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