Blockchain Builder - FreeCryptoStore

Build a blockchain from scratch. Add transactions, mine blocks, tamper with data, and watch the chain validate or break. Adjust difficulty to see how proof-of-work scales.

Mine New Block

Transactions Difficulty (leading zeros) 2

Tamper Test

Block # to tamper New data

Chain Stats

Blocks: 1
Total hashes computed: 0
Avg time/block: -
Chain valid: Yes
Difficulty: 2 (prefix: 00)

How it works: Each block contains data, a timestamp, the previous block's hash, and a nonce. Mining = finding a nonce that makes the block's SHA-256 hash start with N zeros. Tampering with any block invalidates it and every block after it.