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.
Below is an instruction that describes a task, write a response that appropriately completes the request.

### Instruction:
Describe what a blockchain is in less than 20 words.

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