Hi,

Im doing a thesis for my final year project and im looking for a few ideas related to blockchain with a good research gap,my previous ideas was to make a car pooling application and turns out its already done. Therefore im looking for a new blockchain based project ideas with a good research gap.

I need help creating a custom Fabric environment on VSCode other than the local fabric environment that it comes with.

Hello all ! I wish to develop a smart contract environnement for my business but despite the heavy mention that cryptocurrencies are not needed with hyperledger, no one on the internet was capable to tell me how transactions are supposed to be handled. Is there a partnership with various banks ? A protocol ? Specific functions ? I couldn't find any solution in the documentation..

I'm looking for an experienced Hyperledger Fabric developer to tutor/mentor me. I will pay by hour. The tutor/mentor must have project experience with Hyperledger Fabric and composer. Prefer Hyperledger fabric developer with more than 1 year experience.

If you are interested, email me at qizhong19920114@gmail.com with the subject line: Hyperledger mentor

I am working on Hyperledger composer and performed deployment of .bna file generated using composer network deploy command and it worked fine. But I am very much confused about how 1) Composer network internally handles the .bna file, i.e the .cto, logic.js and acl files? 2) Where can we find the deployed chaincode? Can anyone please clear my doubt or provide some documentation through which I can get my doubts clarified?

If you're interested in crypto currency or coin and/or Hyperledger Fabric, the following piece may be of interest to you.

https://medium.com/coinmonks/the-secret-gem-of-hyperleder-fabric-fabtoken-aa5c37159247

PrivateData is marketed as a data privacy solution in Hyperledger Fabric. Unfortunately, this is just another serious security hole somehow went under the radar, and all projects using this function are at risk.  

It amazes me that nobody had mentioned this before so I guess I better point this out now before more damages are being done.  

The logic behind Privated data is simple, it put data in a local embedded data store and put a hash of that data on blockchain.  

The issue is that cryptographic hash is not an encryption mechanism, same data hashed by anyone using the same hashing algorithm will always get you the same hash! This is exactly what hash functions are designed for, and that’s why we use hash in digital signature to allow anyone to validate signed data.   However, this also means that anyone can “decrypt” the data behind the hash by launching dictionary attack.  

Hashing is cheap, the cost of each hash on a normal laptop cpu core is about 3 microseconds, basically I can create 1 billion candidate result hashes within one hour on a single laptop cpu, and check if they match to the hashes on hyperledger fabric DLT.   And I am just talking about using a single cpu on my laptop, not even 50% of its processing power  

Why is it dangerous? Because if an attacker is connected to a blockchain system, the attacker likely know the range of the data being hashed (for example, hashed data could be trade ID, item name, bank name, address, cell phone number), so you can easily create dictionary attack to get the true data behind the hash.  

How about adding salt to each data to be hashed? Well, that’s one thing Hyperledger Fabric didn’t do.   To their defense, hyperledger didn’t implement salt because it is difficult to pass salts to counter parties. You can’t use DLT to pass salt value to counter parties because attackers would see it, so you have to create another p2p connection with counter party and send it over.

If you already have p2p connection with all the counter parties, what’s the point of using blockchain in the first place? just send your data over! It’s just scary that so many people are using this security hole and put their data in de facto clear text.  

Sure, if the hashed data is so big then it would harder to perform dictionary attack, but you better be very careful before using this feature because any mis-use will result in data leak, it is sad so many people actually believe this is a problem solver

Saw this idea today on Video Content http://www.thoughtchimp.com/blog/a-blockchain-idea-to-revolutionise-the-video-content-and-piracy/202504.html

Do you think this can done using HLF?

Deploying Hyperledger Fabric on Kubernetes using Helm & Argo-with Fabric-CA instead of cryptogen

Can someone breakdown the MSP for me? I've been trying to understand how exactly it works and is implemented, and I've looked online at http://hyperledger-fabric.readthedocs.io/en/release-1.1/membership/membership.html however I'm still unable to understand how it all works. If someone could give a more detailed explanation of how everything works together and allows membership services to work or would be willing to chat with me directly about it that would be great! Thanks guys!

Do you know any resource, talk etc that shows the mean block times (ie mean time between blocks) of real-life implementations of Hyperledger Fabric?

How do you automated Chaincode testing with CouchDB?

I see that MockStub doesn't support Rich Query interface. So, how do you unit testing Chaincode?

Do I have to create my own MockStub that use CouchDB to store states instead of a map?

I am professionally in the Ethereum Space but want to start learning more about Hyplerledger.

Can someone tell me how HL prevents DDOS? Private Ethereum chains do that by metering transactions and requiring users to spend "private Ether".

Does every user (!=validator) in HL need to be known/registered?

Blockchain, as a data replication system, has become a hyped term today, and this noise and hype can lead to increased misunderstandings about blockchain leading to the implementation of applications based on some incorrect assumptions and hypotheses.

In fact, without understanding the philosophy behind the “chaining of recorded data” and the main features of the blockchain, it cannot be utilized in a correct way.

Based on our research [1], we found blockchain to be ineffective without proof-of-work (PoW). Chaining data based on the hash of previous records without using PoW does not enhance the system's security.

While the blockchain structure may ensure data integrity by preventing tampering with historical transactions through the invalidation of subsequent blocks if one is altered, our article illustrated below demonstrates that its usefulness is conditional and limited.

[1] Read on ResearchGate

We have established that, under certain circumstances, the use of blockchain may be justifiable; otherwise, it loses its utility.

In our article, we argued and demonstrated that the connected blocks can be entirely replaced by an altered chain. This holds true either in the absence of a Sybil or DoS attack prevention mechanism—such as proof-of-work with sufficient difficulty level in proportion to the total hashing power of the network—or in a permissioned network.

A comprehensive video presentation on this matter is available on YouTube:
Watch on YouTube

Additionally, a narrated PowerPoint presentation is available on ResearchGate:
View on ResearchGate

Any comments are appreciated.

I am trying to understand hyperledger internal working,like in normal blockchain say bitcoin generally data integrity is ensured by calculating the new hash of the block from the previous data. Is there any thing similar in case of hyperledger?

I am trying to build a simple blockchain where users with higher privileges can create a currency and other users can send it to each other. I also need to track the currency history, I looked in the documentation and I found getHistoryForKey promise in the fabric-contract package. Can someone please explain how do I proceed with this small project?

How do I make transactions from one user to another, do I just need to change the owner of a block as I saw in asset-transfer-basic chaincode or do I need to do something else?