The private key is one of the essential tools for encryption and decryption in internet communication, and thus especially for cryptocurrencies. In symmetric encryption methods (also called secret key methods), only private keys are used. The private or secret key is therefore an important tool in cryptography.
What is the Private Key Needed for?
The private key protects your wallet. With hardware wallets, you own the private key yourself and are therefore responsible for your coins and tokens. In contrast, with many hot wallets you do not receive the private key. In that case, the private key is owned by the provider. This is the case, for example, if you store your cryptocurrencies directly on an exchange. Whoever owns the private key of a wallet can therefore dispose of the assets of the wallet.