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Blockchain Training Center In Noida

B - 85, sector- 64, Noida, India.
E-47 Sector 3, Noida, India.
+91 - 8802820025
+91 - 8810252423
012 - 04204716
EMAIL: [email protected]
Blockchain Training Center In Noida
With the neck-to-neck competition in the corporate world, the industry needs to keep up with the latest trends and technology. This increases the demand for professional industry specialists who need to be equipped with the latest and advanced courses to become more competitive and bankable, such as blockchain training in the industrial world.
Blockchain technology has made a big impact in recent years by maintaining public records, healthcare areas, or real estate guarded records and maintaining safe and clear financial transactions.
Let's understand blockchain technology more
A blockchain is actually a chain block list that binds to one another with the help of cryptography codes. Blockchain technology is considered reliable, fair and secure, enhancing the demands of professionals. Blockchain Training Center In Noida
There are many blockchain courses online courses available with major academy acade online academies; NewTime (an academy online academy) tops them all. Ironically, with the demand for blockchain developers, there is a dearth of professionals who are launching a huge pay package and career in the IT world.
Blockchain eliminates the interference of operators in transactions such as governments and large institutions. So making it an open source network that is easily accessible. Blockchain Training Center In Noida
Bitcoin is the first form of digital cryptocurrency that has recently been accepted and globally blocked by its equivalent value against paper, which varies according to their geographical location.
The second most commonly used cryptocurrency is Ferrium, which uses technology as it allows its users to create their own wallet using their network to avoid the coding processes required to wallet. Blockchain Training Center In Noida
Blockchain training teaches a number of topics that understand the key concepts of blockchain. Concepts such as Bitcoin, Ferrium, etc. are described in minute detail. The meaning of blockchain and blockchain concepts is taught in-depth in blockchain training. It gives you a deeper understanding of what Bitcoin is and how it works. One also has an understanding of how ferium is easily used in bats.
Real-world examples are used to teach concepts, making content easy to understand. A comprehensive understanding of blockchain programming can be gained by examining a course from the best institutions, such as the Nitam.
Blockchain training is very important for software professionals, kids and others considering the changes made to the blockchain techno-world.
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submitted by Deependra1092 to u/Deependra1092 [link] [comments]

Tor over VPN, VPN over Tor, or Tor standalone?

It's a widely debated topic as to whether it's appropriate or even safe to tunnel your connection before using Tor. I've made this to give people what I hope to be a better understanding of these processes. This is what the Tor project has to say on the matter This is what Whonix says on the matter
Tor standalone: So your first method is obviously using Tor browser by itself. This can be fine, if someone tries to convince you that tunneling your connection first is necessary, that's a lie. Tor uses anywhere between 3 to 6 keys (whether .com or .onion) to encrypt your transmissions. In addition to this, it implements onion routing (similar to perfect forward secrecy) to prevent each node in your circuit from getting a full, detailed picture of your path. So for instance node 1 can only decrypt the 1st key, it sees the data request is still encrypted and sends it on to node 2 for further decryption, and so on until your transmission is fully decrypted. This provides a very high level of protection in and of itself. If you're just using Tor for general browsing you're probably okay. Your ISP will see you use Tor, but they can't tell what you're doing over Tor. Colluding nodes could be used to deanonyminize you. For instance if your guard and exit are controlled by the same adversary they could find out who you are. I don't really know how many times this method has been used to exploit and reveal Tor users, my guess is relatively low though. Most Tor users get exposed by either bad OPSEC on the user's behalf, or Firefox browser exploits like the Javascript exploit. Never give out personal information over Tor and only use scripts when absolutely necessary. Connect to onion sites whenever possible, no exit node and end-to-end encrypted.
Tor over VPN: This is a method that entails connecting to your VPN app first, then executing the Tor browser. This can be a good setup, albeit a few drawbacks. Without the VPN the Tor guard (or bridge) is connecting to your ISP's assigned IP address. When using the VPN the Tor guard connects to the VPN's IP instead of your ISP's. This essentially prevents your real network from ever connecting to Tor directly. In the off chance of colluding nodes you're much safer, especially if your VPN is not logging your connection, activity, or timestamp (all VPNs log bandwidth). Your ISP will also not see you're connected to a Tor relay. The cons to this is, number one, speed. Tor's not the greatest when it comes to speed in the first place, if your VPN provider happens to be slow it's just going to add on top of the already dismal speeds. Payment method can be a concern, we've all seen that Bitcoin can in fact be exploited. But compared to credit card or paypal it's still your best option. Monero might be a better option but I don't know if VPNs offer that payment method. I would also recommend you download the VPN app over Tor. If you only ever use the VPN with Tor the VPN can never build a profile on you, even if they're logging. Increased attack surface appears to be a concern as well, as Tor project points out. A global adversary with unlimited resources (think NSA) actively working to deanonyminize you specifically could take advantage of your VPN usage. Fortunately, 95% of the Tor users out here are not in danger of the NSA targeting them specifically. So basically your trade off is better protection from ISP, local/state level authorities, and possible corrupted guard nodes for a added vulnerability to the NSA if they so desire to personally go after you. Consider the trade off and choose accordingly to your needs.
VPN over Tor: This is not the greatest setup for several reasons. The biggest being it decreases your anonymity. Connecting to Tor first then the VPN gives your exit the VPN IP not the Tor exit IP. People often complain about the possibility of a Tor exit node that could be snooping on them. The truth of the matter is the exit node never communicates with the guard, and in addition to SSL usage the exit node is never going to find out who you are. However if you put a VPN on the back end of your connection, and it happens to be logging you, they can steadily build a profile of you over time. Tor by itself is trustless, Tor over VPN is trustless, VPN over Tor is bringing a trust factor into a otherwise trustless setup. There's no need for this, just use SSL on the back end to encrypt your connections. Not to mention your Tor circuit is fixed while using VPN over Tor. Your nodes will not change thus bottle necking your entire connection. You also can't connect to onion sites this way either, and for good reason. Also your ISP and guard nodes will connect to each other in this setup. Which if you ask me makes the VPN utterly useless considering one of a VPN's sole purposes is to blackout a ISP.
Additional security recommendations (regardless of VPN usage): Using Linux is preferred to other operating systems for several reasons. No root login by default, little to no data collection on the user, open sourced and patched regularly, viruses aren't common, and less overall exploits. The last few Javascript exploits haven't been useful on Linux or OS X users. I wouldn't count on this being the case every time, but still less likely. Also consider SUID sandboxes like Firejail, MAC protocols like AppArmor and SELiunx, and strict firewall policies that deny all incoming and also deny outgoing on questionable ports. Whonix is also a great way to beef up your security. The link I gave up at top can tell you more about Whonix if you want. Spoofing your MAC address can be helpful as well. Always use full disk encryption and encrypted folders with Veracrypt to put sensitive information in. Using Bleachbit is great way to keep your computer clean from cache, old logs, temporary files, and it can also overwrite deleted data to prevent recovery. There's other programs out there that can do similar things as well.
submitted by Kelceee45 to TOR [link] [comments]

QuarkChain’s sharding technology discussed in more detail

As we can read in the whitepaper, QuarkChain is a blockchain solution which tackles one of the most pressing issues in current blockchain technology: scalability. The most widely used blockchains such as Bitcoin or Ethereum reach an average tps rate (transactions per second) of around 7-10 in their current form – an issue which renders them impractical in a commercial context and thus evoked add-ons such as Lightning Network or Ethereum’s sharding technology that is currently being developed. In contrast, QuarkChain projects to reach up to 1 million tps (current testnet is above 2k tps; see It offers a two-layered architecture consisting of a root chain that is responsible for the confirmation of transaction results through processing block hashes of side chains (= shards; 2nd layer), the latter which function as the ledgers that process the actual transaction data. The project, which is run by an expert team with profound experience in data processing and scalability issues, has received massive attention and is frequently mentioned among the hottest ICOs in the first half of 2018. For a general introduction, please refer to one of the numerous reviews available on multiple platforms such as Reddit, Steemit, Medium or Youtube.
In this post, I pay closer attention to one of QuarkChain’s main features to substantially increase tps on its blockchain, namely sharding. Sharding is a well-known technology for databases to address scalability. In most simple terms, it follows the idea that data and its processing is split-up or partitioned among several hubs (e.g. servers in a centralized environment, or nodes in blockchains). If the entire database of a system is stored, accessed and processed only through a single hub, such an architecture naturally creates a bottle neck that results in significant overheads of data transactions with an increasing user base. Such bottle necks have been directly experienced for example during the CryptoKitties launch on Ethereum last year, or in a centralized environment they frequently occur in ICO whitelisting procedures in which tens of thousands of participants want to access a registration server within the first few seconds after registration opens. Obviously, the dividing of data and its processing onto several servers or nodes without the requirement that all of them have to process the entire data of the system counteracts such bottle necks. The blockchain’s overall transaction throughput is able to scale with the number of shards, and the number of shards typically increases with the expansion of the network and the number of users. Such a form of scalability is frequently referred to as horizontal scalability.
As simple as the idea of sharding is, as tricky is its implementation. We need to have a closer look at different sharding mechanisms that partition different parts of a system to increase scalability and some of the challenges related to these mechanisms.
There exist several strategies which parts of a system are exactly sharded and how. In a blockchain environment, we could, for example, split up new transactions among shards of a network, each shard only processing a portion of these transactions. New transactions are not automatically gossiped throughout the entire network, but only within the responsible shard. Once confirmed in the shard, these transactions can be then put on the blockchain. This would be an example of transaction sharding.
In contrast, we might not only split up the processing of new transactions, we might split up the entire transaction history, i.e. the state of the blockchain at a given point in time, among several nodes so that not every node has to store and process the entire state of the blockchain. This is then called state sharding.
While these two examples offer different advantages to increase overall scalability of a blockchain, there are several technical details to be considered that each bear their own security risks. One of the most important issues concerns the consensus between shards. If shards of a blockchain are able to process parts of the system independently from other shards, how can we ensure that all shards share the same state of the blockchain? And how can it be avoided, for example, that one user spends some of his balance in one shard and also spends it again in another shard (= double-spending), if the shards act independently from each other? Moreover, there is the question how to process transactions between two users that are not part of the same shard in the network (= cross-shard transactions). How can user A that is part of shard 1 interact with user B of shard 2, if the shards of the network act independently?
A sharded network therefore needs some form of consensus mechanism that ensures the overall integrity of the system and allows for interaction between its shards. One of the dilemmas involved here is that the more we increase the interconnectivity of the shards, the more data transfer between shards is required, which in turn has negative effects on the scalability. However, as pointed out above, a lack of interconnectivity endangers the integrity of the system, makes malicious attacks on the network easier, and interaction between users of different shards more difficult. In addition, it is intuitively comprehensible that a single shard of a blockchain network that consists only of a fraction of the overall hash power can be easier taken over by an adversary than a network in which all nodes share all data (= single shard take-over, cf. QuarkChain whitepaper p14). There is, therefore, a true trade-off involved between scalability and security of a blockchain network when it comes to sharding.
Based on this background, let’s review QuarkChain’s sharding architecture and see how it addresses some of the challenges outlined above. As it was already stated in the beginning, QuarkChain’s main structure consists of two layers, (1) a single root chain and (2) multiple flexible side chains (= shards; cf. Figure 4 in QuarkChain whitepaper v. 0.3.4).
Current blockchain technology usually processes two major functions at once: 1) The ledger or order book which takes over the processing of transaction data (inputs and outputs such as transferred amount, timestamp, account addresses, etc.). 2) The confirmation or validation of transactions to ensure the integrity of the system, prohibit malicious behavior such as double spending, etc. The most common mechanism to achieve this integrity is PoW (proof of work).
A main feature of QuarkChain Network is the seperation of these two major functions, the side chains processing transaction data and the root chain confirming transactions through processing only the block hashes of the side chains instead of the entire transaction data contained in them (cf. Figure 3 in QuarkChain whitepaper v. 0.3.4).
Based on this architecture, what kind of sharding technique is QuarkChain using? Since the entirety of transactions is no longer processed in a single blockchain by all nodes, instead by multiple sharded chains, the processing of transactions is split up among them and done in parallel, multiplying tps to the extent of coexisting side chains. QuarkChain therefore uses a form of transaction sharding. However, since QuarkChain’s shards are not simply dividing the processing of new transactions but are fully functioning side chains with their own respective transaction histories, QuarkChain’s structure also includes state sharding. In reality, both transaction and state sharding are integrated in QuarkChain through the clustering of nodes. Clustering is QuarkChain’s mechanism in which multiple nodes, each which process only a sub-set of side chains and/or the root chain, can join together to build a “super-full node” (cf. QuarkChain whitepaper p.24; cf. Figure 7(A) in QuarkChain whitepaper v. 0.3.4).
As long as the conjoined nodes are honest to each other and able to represent the entirety of side and root chains, they can cluster together and form such a full node. In other words, the different nodes in QuarkChain’s blockchain are not simply distributed on the independent side chains or the root chain, nodes of the different shards and the root chain are connected in such a cluster, and even more so, a single node of a cluster itself is able to participate in more than one chain (cf. Figure 7(B) in QuarkChain whitepaper v. 0.3.4).
QuarkChain’s overall architecture, while strongly sharded, simulates a conventional, unsharded blockchain in which each node processes the entirety of data. QuarkChain realizes this through clustering of multiple smaller nodes that together form a full node to validate the entire chain structure of the system.
With its 2-layer architecture, QuarkChain offers its own unique approach to simultaneously tackle 2 issues of sharding at once:
1) The interaction of otherwise independent shards to ensure the overall integrity of the network. This is mainly achieved through two mechanisms: First, the existence of a root chain on top of the shards that collects and integrates the block hashes of all shards. Second, the clustering of nodes in which all chains must be represented to cover the entire network. While the different nodes of a cluster only process parts of the system, a single full cluster covers the entire system including the two major functions of ledger and confirmation (cf. above). If my understanding is correct, in this collaboration the overall consistency of the root and side chains is first established within one such full node and then compared with other full nodes to reach consensus and integrity of QuarkChain.
2) The comparatively low requirements to successfully attack and take over shards. Since shards consist of only a small portion of the overall hash power in a system, they can be attacked and manipulated comparatively easy. However, the addition of a root chain that stores block hashes of all side chains represents a security layer that requires any attacker not only to overpower nodes of the attacked side chain, but additionally s/he has to gain control over the root chain. In order for a manipulation of a side chain to become accepted by the network, the manipulated hash history of the side chain has to be synchronized with the root chain. A very interesting feature of QuarkChain technology is its flexible attribution of hash power to the root chain. Currently, QuarkChain dictates that at least 50% of the overall hash power has to remain on the root chain. Consequently, any attacker of a side chain has to acquire an additional >25% of the overall hash power, namely >50% of the root chain’s hash power. Depending on the required security level, this amount can be adjusted. The higher the root chains hash power, the higher the overall security of the system.
One open question regards how it is decided, which node joins which of the shards and root chain. Imagine nodes having free choice to join any shard in the system. This could pose a tremendous threat to the blockchain, since malicious nodes could easily cluster together and take over a single shard. One option to solve this problem would be randomization. Nodes cannot choose the shard in which they participate but are automatically attributed to one. Usually, such randomization goes hand in hand with periodic reshuffling in order to decrease predictability of the system. However, as we have seen, QuarkChain is much more resilient against such single shard take-overs due to the root chain that has to be controlled in addition to any attack on a shard. QuarkChain is therefore able to offer a different solution. Based on a game-theoretic approach, miners can indeed choose which chain to join, however, they are incentivized to evenly distribute on the shards through varying difficulties and rewards to solve hash puzzles. This feature empowers miners to decide on themselves based on their specific hash power, which shard or root chain is most profitable to mine without the need of mining pools to remain competitive.
QuarkChain’s sharding technology comprises an entire portfolio of features and mechanisms, and this article only scratched the surface. Among the open points remain, for example, the precise functioning of cross-shard transactions, or the handling of multiple wallets belonging to different shards of the blockchain. In addition, note that sharding represents only one of QuarkChain’s core features, others being the support of off-chain transactions, EVM, cross-chain transactions, and others.
Nonetheless, I hope this article unraveled some of the intricacies surrounding sharding technology, as well as some of the issues related to it. Next to QuarkChain, other projects such as Zilliqa or OmniLedger offer sharding solutions, each with their own strengths and weaknesses. Overall, sharding in general and QuarkChain in particular offer a very promising solution to tackle the scalability of open blockchain systems.
As I am not a programmer or blockchain expert by training, I encourage CONSTRUCTIVE responses/feedback/critique and would like to further discuss the strengths and weaknesses of QuarkChain. Questions of any kind are equally welcome.
Further readings: QuarkChain Whitepaper:
Technical meetup with presentation by QuarkChain Founder Qi Zhou:
OmniLedger technical paper:
Article on sharding and blockchain by Zilliqa CTO Yaoqi Jia:
submitted by AffectionateZucchini to QuarkChain [link] [comments]

Bitcoin: How to use Bitcoin ?  Digital cryptocurrency bitcoin-cli and bitcoind - Breaking Down Bitcoin Ep. 2 Bitcoin Q&A: Honest nodes and consensus Blockchain/Bitcoin for beginners 6: blocks and mining, content and creation of bitcoin blocks Who Pays the Bitcoin Mining Reward? - George Levy

This figure represents a 314% increase in 24 hours and there is also an 8.8% and 36.8% increase in the number of nodes and channels respectively. Improvements like the Lightning Network have made ... Ethereum tops crypto blockchains with the highest number of devs, March 2019. Bitcoin has 49 active core devs, the analysis says. That excludes Lightning Network, Bitgo and for ethereum it counts only Solidity changes as “core code” with eth having about 100 active core developers each month. They are in it neck deep whether or not they invented it. Judging by their past behaviour, current involvement and future plans for the rest of humanity it is my opinion that the threat level should be at least orange. More like DEFCON 4.5. Trap number two: pay your taxes. So what is the truth about bitcoin? The Pros & Cons of Bitcoins. Strangely enough, I think the infiltration is exactly ... I am trying to understand the role played by various nodes in the Bitcoin Network in verifying the transactions that are taking place in real time. I think that I understand the process of Transaction (using Input and Output Scripts) and how the Transaction is formed. However I am trying to correlate it with how a Transaction is Broadcasted to other nodes and then verified? Consider an example ... use the following search parameters to narrow your results: subreddit:subreddit find submissions in "subreddit" author:username find submissions by "username" find submissions from ""

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Bitcoin: How to use Bitcoin ? Digital cryptocurrency

The maximum number of Bitcoins will be about 21 million. A bitcoin is a unit of measurement, but the “unit” depends on solely on how people value it in transactions. No physical existence. Bitcoin Miner vs Full Node - Programmer explains - Duration: 7:01. ... How did we get to the current number of bitcoins in circulation? - George Levy - Duration: 4:09. George Levy 609 views. 4:09 ... We start by taking another look at the website to see some sample blocks and then to a quick screencast explaining how new, unconfirmed transactions are collected by mining nodes ... The number of confirmations is the number of blocks that have been added to the blockchain after a transaction is confirmed. For example, if a transaction is in one block, it has 1 confirmation ... Bitcoin is a digital cryptocurrency which can be stored in wallet, its just a alpha-numeric one, if its lost we can recover it easily and it can't be hacked too. If a person has large number of ...