Describe what a blockchain is in less than 20 words.
A blockchain is a decentralized, digital ledger of transactions recorded on multiple computers and secured through cryptography.
Complete the following task based on the instruction and optional input provided.### Instruction:
Describe what a blockchain is in less than 20 words.

### Output:
A blockchain is a decentralized, digital ledger of transactions recorded on multiple computers and secured through cryptography.