What is a crypto block and how does it work?

What is a crypto block?

A crypto block is a virtual block within a blockchain in which transactions are collected and recorded. This takes place in a digital ledger that stores all transactions occurring within a decentralized network. Every time an interaction takes place within the network, it is grouped into a crypto block. Such a block contains information about the transactions themselves, as well as a timestamp and a reference to the previous block. This approach creates a chain of blocks, which explains the name blockchain.

In short: a blockchain is a collection of crypto blocks.

Key Takeaways

• Crypto blocks are data structures within a blockchain in which transactions are bundled and recorded chronologically, creating a transparent and verifiable transaction history.
• Each crypto block is cryptographically linked to the previous block via hashes, making retroactive changes practically impossible without full network control.
• Blocks are validated and added through consensus mechanisms such as Proof of Work or Proof of Stake, where miners or validators collectively secure the network.
• Through block explorers, the contents of blocks are publicly accessible, including transactions, timestamps, fees and block producers, while wallets present this data in a user-friendly way.
• Thanks to this block structure, blockchains can operate without a central intermediary, ensuring decentralization, reliability and resistance to fraud and censorship.

How does a crypto block work?

A crypto block works like a digital box in which information is stored. It works as follows:

• A user initiates a transaction.
• The transaction is temporarily collected and stored within the network.
• When enough transactions are available to fill a block, they are grouped together in a block. How many transactions are stored depends on the block size of the blockchain.
• The transactions in the block are validated for legitimacy through a consensus mechanism , such as Proof of Work (PoW) or Proof of Stake (PoS). This often happens through mining or staking.
• After approval, the block is added to the blockchain and distributed to all nodes within the network. This way, everyone has the updated version of the blockchain.

New blocks are continuously added to the blockchain, repeating this cycle 24/7.

What does a crypto block look like?

A crypto block visually appears as a collection of data fields. This data is public and can be viewed via a block explorer. Every blockchain has its own block explorers, so a block explorer only shows block information from that specific network. Example: Etherscan is a well-known block explorer for the Ethereum network.

These are the data points shown in a block explorer:

• Block number
  Each block has a sequential number within the blockchain.
  Example: Block #825,431

• Hash of the previous block
  This is a long string of letters and numbers that refers to the previous block in the blockchain.
  Example:
  00000000000000000005a3f9c8e2b7a1d4f6e91b2c3a0f8e7d6b1a9c4e2

• Own block hash
  This is the unique cryptographic fingerprint of the current block.
  Example:
  0000000000000000000f1b2e6d9a4c8e3f7b5a1d0c2e4f6a9b8c7d5

• Timestamp
  Indicates when the block was created.
  Example:
  2026-01-05 14:32:18 (UTC)

• Transactions
  A block contains multiple transactions. Each transaction has a sender, recipient and amount. The sender and recipient are wallet addresses.
  Example of a single transaction in a block:
  From: bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh
  To: bc1q9z3d8f7g5h4k2l0m8n6p4r2q1w5y7x9
  Amount: 0.015 BTC

• Number of transactions
  Indicates how many transactions are included in the block. This varies per block and per network.

• Block size
  Shows how much data the block contains. Each network allows its own maximum block size.
  Example: 1.34 MB

• Transaction fees (fees)
  Shows how much in transaction fees users collectively paid for inclusion in this block. These fees often form part of the reward for the block producer.

• Block reward
  The reward paid out for creating the block. This can consist of newly minted coins, transaction fees or a combination of both, depending on the network.

• Block producer (miner or validator)
  Indicates which miner (in proof of work) or validator (in proof of stake) created and proposed the block to the network.

• Block header (summary)
  The block header contains the most important technical data, such as hashes and time information, and is used to verify the block. Users usually do not see this directly, but the network uses it to secure the blockchain.

As a user, you only see the most essential information, but behind the scenes much more is happening. Within wallets and block explorers, technical data is translated into clear overviews with transactions, amounts and confirmations. Behind the scenes, however, each crypto block consists of these fixed, verifiable data points, which together ensure the security and immutability of the blockchain.

Why do crypto blocks exist?

Crypto blocks exist to carry out transactions within decentralized networks in a safe and transparent way. Instead of relying on a single central party such as a bank, decentralized networks depend on collective control and storage of transactions and other data. In practice, thousands of nodes or miners are active within the network to secure it, add new blocks and validate transactions. This makes the network decentralized, fair and resilient to outages when one of the validators stops functioning.

Because all data is open source, malicious actors can be detected early, increasing security and reducing the risk of fraud within the network. In addition, transactions are carried out peer-to-peer, meaning there is no intermediary involved. There is therefore no bank or institution that must first approve your transaction.

Can blocks be modified?

Blocks cannot be modified in principle. The blockchain is immutable: blocks are added sequentially to the blockchain and are linked to the previous block. This means that changing a single block would require all subsequent blocks to be changed as well. This requires an enormous amount of computing power and network control, making it practically impossible for large blockchains. This immutability is one of the key characteristics of blockchain technology and ensures trust and reliability. Only in extreme cases could this be possible, for example through executing a hard fork. With a hard fork, the blockchain splits and continues along a new path.

In the past, hard forks have been carried out on both Bitcoin and Ethereum. On Bitcoin, Bitcoin Cash emerged after a disagreement over network scalability and the maximum block size. Part of the community wanted larger blocks to process more transactions per block, while the original Bitcoin network stuck with smaller blocks.

On Ethereum, a hard fork took place after the DAO hack in 2016. Due to a vulnerability in a smart contract, a large amount of ether was stolen. The majority of the community chose to undo the consequences of this hack through a hard fork. As a result, the blockchain split into Ethereum, which implemented the change, and Ethereum Classic, which retained the original history.

Final thoughts

Crypto blocks form the core of blockchain technology. By bundling, verifying and immutably recording transactions, blocks create a transparent and reliable system without a central intermediary. The fixed structure of a crypto block, combined with cryptographic links and consensus mechanisms, makes manipulation practically impossible. Thanks to block explorers, this information is publicly accessible, while users can interact with the network easily through wallets. This combination of technical certainty, decentralization and transparency makes crypto blocks essential for the functioning and reliability of blockchain networks.