Follow the Chain — TechKnowSurge

About this interactive

Blockchain is older than cryptocurrency. The idea is integrity: if old records are stored in blocks, nobody should be able to go back and quietly change one. In the lesson's model, a block has a number, a place for data (often a ledger of transactions), a field for the previous block's hash, and its own hash, which covers the data and that previous hash. Block 1 has no block before it, so its previous-hash field is all zeros. Block 1's hash goes into block 2, block 2's hash into block 3, and so on. Now change something in block 1. Block 1's hash changes, so it no longer matches what block 2 recorded; fix that and block 2's hash changes, which breaks block 3, and so on. You cannot change a block without affecting every block after it, and hashes that do not line up flag an integrity problem. Because the data's integrity can be checked, the work does not need one central machine, which would be a point of weakness. Many servers hold the same chain and keep each other accountable: if one copy is off, the others notice and do not accept it, and it is brought back into line. A ledger copied across many machines is a distributed ledger. Many cryptocurrency ledgers are also public, so anyone can download them, and anyone who knows your account number can track your purchases.

What you'll learn

Trace how chained hashes expose tampering: each block stores the previous block's hash, so changing an old block changes its hash and breaks the link to every block after it
Recall how a distributed ledger works: many servers hold the same chain with no central machine, notice a copy that is off, and, on a public ledger, let anyone see the transactions

Aligned to

CompTIA Security+

1.4 Explain the importance of using appropriate cryptographic solutions.

3.1 Compare and contrast security implications of different architecture models.

ISC2 CISSP

3.6 Select and determine cryptographic solutions

NIST 800-53

SC-13 Cryptographic Protection

SC-36 Distributed Processing and Storage

NIST CSF

PR.DS-01 The confidentiality, integrity, and availability of data-at-rest are protected.

PR.IR-03 Mechanisms are implemented to achieve resilience requirements in normal and adverse situations.

ISC2 CC

5.1 Understand data security

Key terms

Blockchain: A chain of data blocks where each block contains a cryptographic hash of the previous block, creating a tamper-evident linked sequence that preserves data integrity.
Block: A discrete unit in a blockchain that stores data and a cryptographic hash, linked to the preceding block to form an immutable chain.
Hash Function: A mathematical algorithm that converts input data of any size into a fixed-size output value used to verify data integrity.
Data Integrity: The assurance that data has not been altered or corrupted during storage or transmission.
Distributed Ledger: A record of transactions or data that is replicated and synchronized across multiple nodes or machines with no single central authority.
Decentralization: An architectural approach that distributes processing and data storage across many independent nodes rather than relying on a single central system.
Cryptocurrency: A digital currency that uses cryptographic techniques and blockchain technology to secure and verify transactions without a central authority.

Topics

Blockchain Data Integrity Distributed Ledger Interactive Fill In

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