Toms Blog

Where I talk about Bitcoin Cash and more

Are SPV payments safe?

2018-01-27 Bitcoin cash

There are still a lot of misconceptions out about SPV wallets, people make it seem like they are less useful than they are, and this is a shame.

SPV wallets are wallets with “Simplified Payment Verification”. A term that actually shows up in the original Bitcoin whitepaper from Satoshi Nakamoto.

The trick is that SPV wallets (which in practice is almost all wallets) check all the Bitcoin blocks, validate if the miners did their work but they do not download and check all the transactions. This limits the download and check of the entire 8 year blockchain to about 39 MB. Pretty neat eh?

So, what are people worried about?

Continue reading

A roadmap for scaling Bitcoin Cash

2017-11-02 bitcoin cash
I have been measuring the performance and optimising it for over a 2 years now, when I first looked we had 368 million transactions a day. Today with better software and faster hardware we are closer to a 900 million a day. This means that today, the software on modern hardware has a peak-performance in ideal situations which is about equal to Visa peak levels 10 years ago. These numbers are not sustainable because of various reasons. Continue reading

Quadratic scaling of hashing time

2017-07-11 bitcoin
Theory In Bitcoin a transaction moves money from one address to another and in order to only allow the actual owner of money the ability to move this, we use cryptographic signatures. An owner of a Bitcoin address can only spend money by adding a cryptographic signature to a transaction that spends it. The act of adding a cryptographic signature includes the hashing of the entire transaction. As such the size of the transaction matters to the speed of this signing, as well as the validation of said signature. Continue reading

UTXO Growth

2017-02-16 bitcoin
Over the last year we have seen quite a lot of people that get worried about the UTXO growth. Lets find out why. For those catching up; the UTXO is the Unspent Transaction Output database. The essential database that is needed to find out if a new incoming transaction is actually spending money that exists. The growth is explained well in this blog from Gavin Andresen, the blog is already older, so the growth has continued. Continue reading

Scaling Bitcoin on chain

2016-07-11 bitcoin
One of the most talked about topics in 2016 when it comes to Bitcoin is the lack of a good plan for growing and scaling the system into the future. I find this curious, as anyone that starts to depend on any system should do at least some investigation on what kind of growth it can handle and whether it can actually do what we want it to, this year and 5 years or longer into the future. Continue reading