## 5 - Transactions

### Overview

A self-explanatory term, transactions are the mechanism that allows us to send value across cyberspace.

### Transaction Properties

- **Transaction Lifecycle**  
  00:00  
- **Transaction Inputs and Outputs**  
  02:30  
- **Digital Signatures**  
  04:49  
- **Summary/Recap**  
  18:00

### Key Terms

- #### Digital Signature

In the context of blockchain networks, a **digital signature** is attached to a message or transaction to prove that the sending user has adequate permissions. To create a digital signature you require the private key (a.k.a. signing key) associated with the public key of the sender of the transaction.

### Practice Questions

Test Yourself  
- [Lesson 4 - Wallets](/content/blockchain/blockchain-fundamentals/wallets/index.html)  
- [Lesson 6 - Blocks](/content/blockchain/blockchain-fundamentals/blocks/index.html)