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Cryptocurrency Ethereum Mastering Development

Which operations can change ethereum address balance?

I am writing a program that would monitor changes in balance of a set of ethereum addresses. I did the same for UTXO based coins, and the logic was pretty simple. All of the changes were directly recorded in blocks. But ethereum appears to be more complicated. Which operations I have to monitor to be […]

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Bitcoin Cryptocurrency Mastering Development

Why this ugly looking formula to calculate ‘target’ from ‘nBits’ in block header: target = coefficient * 256**(exponent-3)

Why this ugly looking formula to calculate ‘target’ from ‘nBits’ in block header: target = coefficient * 256**(exponent-3). Why not? : target = coefficient * 256**(exponent). What is the need of subtracting 3. All we need is to be able to generate 256 bit long number and enough precision (which we already have with 3 […]

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Cryptocurrency Ethereum Mastering Development

Creating Multiple ERC721 Tokens

Imagine you wright your own token following the ERC721 standard. Now you want to create 10,000 tokens of this type. Do you need one contract to manage each token? Do you have to deploy 10,000 token contracts? Can you manage all tokens with one single contract? The use case I was thinking about was creating […]

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Cryptocurrency Ethereum Mastering Development

Lightweight Ethereum client for Android and IOS

Are there any available Lightweight version of Geth or Parity client on Android or IOS in order to avoid using Infura service when accessing blockchain form a mobile app?

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Cryptocurrency Ethereum Mastering Development

Generate directory hash without upload using Swarm API

I am using the Swarm API (github.com/ethersphere/swarm/) with go to upload a directory on a private network. The client API(/api/client) provides a UploadDirectory function which returns a manifest hash. Is there a way to calculate the same Merkle Tree hash without uploading the files to the Swarm storage, preferably with the API ? The reason […]

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Cryptocurrency Ethereum Mastering Development

Infura: “project ID request rate exceeded” despite minimal requests

Looks like I’m being rate limited by Infura, despite making nowhere near the 100,000 request/day limit under Infura’s Core plan. truffle migrate and truffle test both produce VM Exception while processing transaction: Error: Returned error: Returned error: project ID request rate exceeded. I even created a new Infura project and used that new project ID, […]

Categories
Bitcoin Cryptocurrency Mastering Development

Why this ugly looking formula to calculate ‘target’ from ‘nBits’ in block header: target = coefficient * 256**(exponent-3)

Why this ugly looking formula to calculate ‘target’ from ‘nBits’ in block header: target = coefficient * 256**(exponent-3). Why not? : target = coefficient * 256**(exponent). What is the need of subtracting 3. All we need is to be able to generate 256 bit long number and enough precision (which we already have with 3 […]

Categories
Cryptocurrency Ethereum Mastering Development

Infura: “project ID request rate exceeded” despite minimal requests

Looks like I’m being rate limited by Infura, despite making nowhere near the 100,000 request/day limit under Infura’s Core plan. truffle migrate and truffle test both produce VM Exception while processing transaction: Error: Returned error: Returned error: project ID request rate exceeded. I even created a new Infura project and used that new project ID, […]

Categories
Cryptocurrency Ethereum Mastering Development

Infura: “project ID request rate exceeded” despite minimal requests

Looks like I’m being rate limited by Infura, despite making nowhere near the 100,000 request/day limit under Infura’s Core plan. truffle migrate and truffle test both produce VM Exception while processing transaction: Error: Returned error: Returned error: project ID request rate exceeded. I even created a new Infura project and used that new project ID, […]

Categories
Cryptocurrency Ethereum Mastering Development

How do you normalize client-side web3 libraries?

In my web front-end, I need the ability to interact with the Ethereum blockchain. It’s possible a user has MetaMask installed. It’s possible a user is using the web without MetaMask installed. It’s possible a user is using an old dApp browser. It’s possible a user is using a modern dApp browser. The following code […]