Cryptocurrency is a type of digital currency that uses cryptographic techniques to secure transactions and control the creation of new units. Cryptocurrencies have several key characteristics:

1. **Decentralization**: Most cryptocurrencies operate on decentralized networks, meaning they are not controlled by any central entity such as banks or governments.

2. **Encryption**: Encryption techniques are used to protect transactions and ensure the integrity of data, making them resistant to tampering and fraud.

3. **Instant Transfer**: Cryptocurrencies can be transferred quickly over the internet, facilitating international transactions without the need for intermediaries.

4. **Transparency**: All transactions are recorded on the blockchain, allowing users to easily verify the validity of transactions.

5. **Privacy**: Some cryptocurrencies offer a level of privacy, where users can make transactions completely anonymously.

### Examples of cryptocurrencies:

- **Bitcoin**: The first and most popular cryptocurrency, created in 2009.

- **Ethereum**: Allows the creation of smart contracts and decentralized applications.

- **Litecoin**: Aims to improve the speed of transactions compared to Bitcoin.

Cryptocurrencies are a controversial topic, with opinions varying on their benefits and risks, including price volatility, regulatory issues, and their use in illegal activities.