
Show HN: Very basic blockchain-free cryptocurrency PoC in Python - Graa
https://github.com/DutchGraa/crackcoin
======
pollyannas
So this is basically a blockchain, but with transactions instead of blocks,
and diverging-then-converging graph instead of a linear sequence of blocks
(like a real family graph instead of just one-parent-one-child families common
in blockchains). Looks nice, what are the problems with the approach? (the
paper only lists the benefits).

~~~
Jabanga
There is no way to have a controlled release of new coins into the system. For
that you need a blockchain that establishes a consensus on time transpired and
on the total economic resources being contributed (which allows the share of
the newly generated coins that each participant will receive in a unit of time
to be proportional to the share of the total economic resources they are
responsible for contributing).

There is no mechanism to link cost of proof of work generated to the value
being transacted. With a blockchain, scarcity of space per block leads to a
fee market forming, and fees paid increasing as the value contained per
transaction increases. This leads to security (proof of work) increasing in
proportion to value that needs to be protected.

~~~
JauntyHatAngle
>With a blockchain, scarcity of space per block leads to a fee market forming,
and fees paid increasing as the value contained per transaction increases.

Note that this is not currently the case in bitcoin, transaction fees have
gone up with the current scarcity due to the arbitrary block limit, but the
fees are still a pittance compared with block reward - which is the real
incentive for mining (but will not always be the case as block reward reduces
in the future).

This is somewhat of a sore point for the bitcoin community as a large
(probably not majority, but large) portion of the user base / miners / nodes
does not think scarcity of space is a good idea at current levels of
transactions.

Also Ethereum (which at the moment uses a blockchain and mining mechanism very
similar to bitcoins) does not impose a block size limit, rather leaves it up
to the miners to decide on the "gas" limit (they have a computational limit
rather than a block size, but it can be viewed as a parallel).

~~~
immad
Number of new Bitcoins a day: 2063 [1] Transaction fees in Bitcoin: 272 [2]

So transaction fees are not insignificant.

1: [https://blockchain.info/charts/total-
bitcoins](https://blockchain.info/charts/total-bitcoins) July 6th data 2:
[https://blockchain.info/charts/transaction-
fees](https://blockchain.info/charts/transaction-fees) July 6th data

~~~
JauntyHatAngle
That's total, not per block.

Per block, fees average 0.9btc iirc.

Transaction reward is 12.5 btc

0.9 is not insignificant, but compared with block reward, the true (current)
incentive providing block security is not in question, and that is what was
being discussed.

~~~
mhluongo
How is that a useless figure? You'd expect it to have the same ratio per block
or per day, so they're comparable when talking about the ratio of fees to
rewards

~~~
JauntyHatAngle
Because we are talking about security of blocks and block scarcity, there is
no limit on the space "per day", its all per block, similarly people don't
make race attacks on a day, they make race attacks on a block.

------
jchanimal
Reminds me of a cryptocurrency for the gift economy that I'm working on. Each
coin is unique and valued subjectively by each person.
[https://github.com/jchris/document-coin](https://github.com/jchris/document-
coin)

~~~
ErikBjare
Holy shit, I've had an idea just like that in the past.

~~~
Paul_S
I think it's a common idea. I thought of it before bitcoin was a thing (public
signed transactions) and heard similar ideas many times. Still waiting for a
working system because at this point in pretty sure I'll never actually create
one myself.

------
TD-Linux
Note that base58 for addresses was generally considered a mistake - there's a
replacement for Bitcoin proposed here:
[https://github.com/bitcoin/bips/blob/master/bip-0173.mediawi...](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki)

~~~
zik
Note that this proposal is from two authors who are under huge controversy
right now and depending on who you listen to are likely to be removed from
their current positions as Bitcoin contributors along with several others in
the next few weeks. Given this it seems likely that this proposal will go
nowhere.

------
imoskar
Are there any blockchain-free cryptocurrencies currently on any exchange?

~~~
wonderous
IOTA:
[https://coinmarketcap.com/currencies/iota/](https://coinmarketcap.com/currencies/iota/)

Here's the related white paper:
[https://iota.org/IOTA_Whitepaper.pdf](https://iota.org/IOTA_Whitepaper.pdf)

Website is here: [https://iota.org](https://iota.org)

~~~
antocv
Be warned about IOTA though, it still is not decentralized, see
[https://medium.com/@ercwl/iota-is-
centralized-6289246e7b4d](https://medium.com/@ercwl/iota-is-
centralized-6289246e7b4d) and the reaction of devs/foundation-members to that
article, does resemble the reaction when somebody has something to hide. And
[https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_wi...](https://www.reddit.com/r/Iota/comments/6jzfak/whats_wrong_with_iota/)
and some others, but also the official channels are moderated/censored.

Seems to be more promise, hype abd marketing, than what it says on the tin.

~~~
TD-Linux
Even disregarding any flaws, I'd still consider it a blockchain - just one
where each block only holds a single transaction.

~~~
antocv
Yes.

Having said that, the positives about IOTA;

They seem to have developed their own hashing function, of the sponge family,
called Curl - and are actually using the Westernelitz (oh jesus spelling, more
space-efficient Lamport) signature scheme - it is a method of constructing a
digital signature only from hash functions. Cool.

------
Temasik
the only public blockchain-free cryptocurrency in top 10 of coinmarketcap is
iota

www.iota.org

------
fiatjaf
Yeah, I'm done with this "scientific" tone, this PDF thing and so on. What is
in this paper that couldn't be posted as HTML in a web page? How is PDF better
compared to that?

~~~
mycomian
Are you trolling? It's a scientific paper.

~~~
yosito
Are you trolling? HTML was invented for scientific papers.

~~~
literallycancer
Try reading the HTML version of Fielding's paper and tell me it looks better
than the pdf. It might have been invented for that purpose, but that doesn't
mean it's still suitable for it. When you are writing a paper, you want to
control the presentation, not just the content.

~~~
cocktailpeanuts
I'm pretty sure you have way more control over "presentation" when you use
HTML vs PDF.

~~~
tempay
No you don't, HTML has massive variation between devices and what software is
used to display it. Try setting your screen resolution to 640x480 and opening
a webpage or, even worse, modifying DPI. PDFs on the other hand specify
exactly where to place each glyph (admittedly there is still variation between
software but it's much more consistent).

~~~
dahauns
You sure do - the variation between devices _is_ the manifestation of the
ability to control layout depending on the recipient's display's resolution
and size.

If anything, a PDF designed for A4/letter is going to be cumbersome to read on
a (probably rather small) 640x480 display.

The sad state of PDF rendering on (most) e-book readers should be evidence
enough.

