If you deal with cryptocurrency, then you’ve certainly come into contact with a blockchain at some point.
But what data do blockchains store?
And, if these blockchains are public, should you be worried about what’s on them?
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Blockchains are best imagined as virtual chains of blocks, hence the name.
Each block stores data using hashing, a cryptographic method.
This stops illicit individuals from exploiting blockchain data.
Blocks vary in size, meaning the amount of information they can store differs.
A Bitcoin block, for example, is only 1MB in size.
The same goes for Litecoin and Dogecoin.
Instead, let’s get started with the kind of data stored on the blockchain.
What Data Does a Block Store?
So far, over 760,000 Bitcoin blocks have been mined, with around 900 BTC put into circulation daily.
Bitcoin is coming close to itssupply limit of 21 million BTC.
Once this cap is hit, no more BTC can be mined.
The data within a Bitcoin block is hashed using the SHA-256 cryptographic hashing algorithm.
Different cryptocurrencies use different hashing algorithms.
Ethereum, for example, uses Ethash.
Many governments use SHA-256 to hash data, too.
A Bitcoin block consists of a few different sections.
Let’s start with the block header.
Blocks store transactions in chronological order.
This is the number that a miner must reach by solving computational problems.
If a miner solves the nonce, they can successfully mine the block.
Next up, we’ve got thebits.
This field also relates to Bitcoin’smining difficulty, as it contains the difficulty itself.
This can increase or decrease over time.
If the difficulty increases, a miner must use more hash power to mine the block.
If it decreases, the miner can use less.
Of course, miners prefer a lower difficulty as this saves energy and time.
In general, if the number of miners increases, the difficulty increases with it.
ThehashMerklRootis associated with a Merkle Root.
hashPrevBlock, as the name suggests, refers to the 256-bit hash of the previous block.
Every Bitcoin block on the chain contains the hash of the previous block.
Lastly, you’ve got theversion.
This field simply refers to the version of the Bitcoin protocol that was used.
Updates are made every now and then to improve certain parts of the connection.
The most recent protocol version is 70015, which was introduced in 2017.
This update provided the ability to ban invalid compact blocks from the chain.
The Remainder of a Bitcoin Block
But things don’t stop at the header.
This field imposes a limit on the amount of data that can be stored within a block.
As previously stated, Bitcoin’s block size limit is 1MB, but this changes from crypto to crypto.
Thetransaction countersimply counts the number of transactions recorded within a given Bitcoin block.
There is no constant number of transactions that blocks store, as each transaction can have a different size.
Magic numbers also stand as a connection identifier for each block.
This constant value was set by Satoshi Nakamoto when Bitcoin was created.
Does the Blockchain Store Your Personal Data?
Your name, contact details, payment information, and other private data are not stored on the blockchain.
The only data that does relate to you is your public wallet address.
In most scenarios, this is totally benign.
Most cryptocurrencies out there are pseudonymous andtraceable to a degree.
