...by Daniel Szego
quote
"Simplicity is the ultimate sophistication."
Leonardo da Vinci

Thursday, October 18, 2018

Fabric composer tips and tricks - return value of a tansaction


Unfortunately there isn't possible to return value from a transaction in Hyperledger Fabric Composer. What you can do however:

- Emitting an event, like

  let retValEvent = getFactory().newEvent(namespace, 'RetValEvent');
  retValEvent.RetValue = "value";
    emit(retValEvent);

- writing the return value into the variables of an asset or participants. For fine-tuning the access rules, it might be possible to define a separate asset containing only the return values of the different transactions:

  asset ReturnValueAsser identified by retId {
    o String retId
    o String retValTransaction1
    o String retValTransaction2
    --> RelatedAsset relatedAsset
 }



Tuesday, October 16, 2018

Top Blockchain applications making waves in commercial real estate


A guest article republished from RealAtom written by Karl Utermohlen.


What Is Blockchain?
Blockchain technology is a way to store and transfer information in an encrypted manner by distributing data instead of copying it in a central location. Blockchain does so through a cloud, peer-to-peer network that eliminates the need for a third party, which ultimately reduces transaction fees. A digital ledger is then created and updated with each financial transaction in blocks.
There are plenty of benefits to making transactions and transferring data using blockchain as the technology is not controlled by one central entity, such as a central bank. This means that breaching these blocks is extremely difficult, maintaining the sanctity and transparency of its transactions and data.Blockchain is the backbone of cryptocurrencies such as Bitcoin, which offer speedy and low-cost ways of sending and receiving money.

Faster Transactions
One of the most exciting ways blockchain is disrupting the CRE world is in the form of smart contracts. The industry currently relies on an inefficient system of old-school verification of property ownership by conducting research to ensure the property belongs to the party who is selling it.
Blockchain can reduce the speed in which the chain of custody regarding CRE properties takes place as a property’s title would be stored on a public ledger. This would remove the need for another central repository, thus reducing transaction, state, city and legal costs. The same principle would apply for leases that would be recorded via blockchain.

More Transparent Deals
Blockchain can also ensure that real estates assets are more liquid and the terms of the agreement are fully understood by both sides as every piece of data regarding a property would be stored publicly. This includes data surrounding former owners, construction done on the property, past maintenance costs and records regarding former inspections.
Having all this information available would give the investor a more comprehensive idea of the property they are investing in. Blockchain essentially ensures that everyone is on the same page and both sides are fully aware of what they’re getting into as every piece of information is out there for anyone to access.

Digital Paper Trail
Another challenge with the CRE industry is the fact that public records can be outdated, unreliable or not available. Following a property’s paper trail can be time-consuming and frustrating as a lot of this information is lost due to poor organizational skills from industry workers and legacy systems that lose data when updated.
With blockchain, every piece of information on a property would be available in the same place rather than in multiple physical and digital domains. Blockchain would also help to eliminate the type of fraud that sometimes exist in the industry as deeds and titles can be counterfeited easily.

Buying Property With Cryptocurrencies
As previously mentioned, Bitcoin is a cryptocurrency that relies on blockchain to complete financial transactions online in a matter of seconds. Some investors and real estate firms have started adding Bitcoin to the industry, including Ivan Pacheco, who bought a two-bedroom condominium in Florida for $275,000 in Bitcoin.
In the residential space, you can buy a condo on the Lower East Side of Manhattan with Bitcoin. Meanwhile, some apartments in New York City are allowing their tenants to pay for rent using Bitcoin. Cryptocurrencies have been historically volatile and they’ve been on the decline since peaking in December 2017, but some investors believe that the future of real estate will be closely tied with Bitcoin and other digital coins.
Nevertheless, blockchain’s role in the CRE industry is becoming more prevalent each day. The technology’s potential to speed up transactions with smart contracts, its ability to add transparency to a deed or title and the fact that it dramatically decreases the chance for fraud suggest that more investors will flocks towards firms that use blockchain for CRE transactions.

Smart browsers: on web browser and crypto-blockchain integration


The next stage of the blockchain-crypto adaptation might be if we imagine strong integration possibilities between web browsers and the blockchain crypto space. One similar example is metamask that provides several useful functionalities that can be used with decentralized applications driven by ethereum. Metamask is however only a plugin for chrome. Web browsers should support blockchain - crypto applications in a native way. Actually, there should not be very much difference between a web browser and a crypto-wallet. Instead a new concept should be introduced, Web3 browser or perhaps smart browser, that integrates crypto-blockchain functionalities with classical web browser elements. As there are already initiatives in this direction, like Mist wallet, however Mist is pretty much a geek tool without having too much support for standard users. Successful smart browser, or Web3 browsers should be initiated by traditional browser providers.  

Monday, October 15, 2018

Identity is a scarce resource in consortium blockchain


To avoid a naive sibyl attack in most of the decentralized consensus protocols there is a scarce resources that needs to be use in order to take part in the consensus mechanism. This resource is computational power at proof of work and it is a kind of a cryptocurrency at proof of stake. Actually, consortium systems do not differ very much from this idea. In consortium systems, the scarce resource is the identity: only nodes with a special distributed identity are able to participate in the consensus. In this sense it works similarly as the public blockchain networks : the scarce guarantees that none with a huge bot network, but without the scarce resource can influence the consensus voting. 

Sunday, October 14, 2018

Fabric composer tips and tricks - item with ID already exist but not visible


Sometimes if you work with the Fabric Composer online playground and you create an item from a transaction you get the error message that the given id already exist even if it is not directly visible in the asset list. This is actually a "feature" of the online playground, it happens if the old item with the old id already existed but it was deleted. For some reasons it is sometimes cached somewhere that can not be explicitly deleted. What you can do in such situations that you redeploy the business network archive file:
- Make sure that the latest version of the .bna (business network archive) is downloaded.
- Delete the existing business network in the online playground.
- Rdeploy the business network from the downloaded .bna file.

Saturday, October 13, 2018

On the need of zero knowledge order book matching algorithms


There are many ideas for implementing a decentralized exchange protocol on blockchain. As it might be realized naturally with the help of a quorum consensus, it is not so much easy with a Nakamoto one. The problem is that in a Nakamoto consensus, a leader is choosen in each round to create and start propagating the next block. This leader will act as a dictator for the certain block, meaning that it can influence the transactions that will be minded into the block. It might be a DEX realization idea to create sell and buy orders and transactions and realize the matching algorithm with the help of mining, however it can be "gamed" very strongly in a Nakamoto consensus by the given miner. Hence, buying and selling orders can be "gamed" by the rest of the network, like the transactions themself can be delayed or censored. A solution to these problems might be the definition of zero knowledge order matching algorithms, where the creator of the order, and the exact amounts or other order details are hidden by cryptography. Certainly, it is an open question if efficient order book matching algorithms can be defined in such a way.    

Friday, October 12, 2018

Azure Workbench tips and tricks - error log


Azure Workbench is really cool, however if something goes wrong, you do not get too many information from the error details in an easy way. What you have to do, is to use the following  powershell script to download a detailed log and error information:


The script downloads detailed logs and analytics both for the workbench itself and the underlying blockchain. 

Notes on blockchain technology and market segmentation



Having a lot of competing blockchain platforms it is pretty much difficult to identify which platform to use for a certain use-case. The following directions can be considered:
- B2B market: typically consortium blockchain platforms, like Hyperledger. 
- Inter-banking B2B market: here special platforms need to be considered that can satisfy the requirements of the banking sector, like Corda or Ripple. 
- B2C market: here both consortium and public networks can be used. If the users could have a direct access to the blockchain platform than typically public networks, if the technological details are hidden, than consortium ones. 
- C2C market: on a fully decentralized customer to customer market, only public platforms can be used. 


Wednesday, October 10, 2018

Notes on the difficulty of smart contract programming languages


The idea that blockchain programming should be done by anyone is pretty dangerous. The problem is that programming for an immutable ledger for applications that probably store currency and has a lot of business values is difficult. It requires a lot practical and theoretical background, programming skills and quality assurance. Non-statically typed languages, like Javascript provide the possibility for everyone to implement fast small programs, however the language will be very soon a problem as one wants to implement either large scale or mission critical programs. For such highly secure, highly mission critical applications very strictly typed languages with formal verification and strong testing methodologies must be used.   

Tuesday, October 9, 2018

Notes on semi public blockchain networks, Hashgraph and regulation



There is an interesting combination between public and private blockchain networks and that is the sol called semi-public network. In such a field, the network will be operated or governed by several semi-trusted actors, but the network itself from a development or application point of view is open for everybody. However, it is pretty much questionable if that model can work at all. The model is that an application or transaction can only be censored if a majority of the consortium members will vote for that. It is good question what is going to happen on the practical side if an application is not conform with a regulation of a certain region. One model is that an application can only be filtered if most of the regions vote the application out. Exactly the opposite can happen however from the practical side as well, there might be the situation where an application has to be conform not just with one regulation of a certain region but with all regulation of all of the regions.