A private key is a very vital thing from your wallet, like a private key's human body like your heart is your wallet if you give it to someone else like you give your own heart to someone else. Never store large amounts of Bitcoin on an Exchange website for a long time, because the wallet provided by the Exchange site is basically their wallet address especially if the wallet has a generate feature
Just my point. If you want to use cryptocurrency without getting hacked then you need to both create your wallets and make your transactions entirely OFFLINE.
Unlike with traditional banks, you have the power to create accounts (wallets) and transactions by yourself and while your computer is completely disconnected from the internet. To understand how this works lets use ethereum as an example and take a brief look into what makes up an ethereum wallet:
Ethereum wallet is made up of a private key, public key, and address.
The private key is like your accounts password. Its used to sign transactions (think sign off or approve). It should never be shared with anyone. Its a long string of text that is randomly generated when you create your wallet.
0x3a1076bf45ab8..................................fdd9a537d8fe266
The private key is used to generate an even longer string called a public key. Public keys are used to validate transactions with the private key. You can learn about how public-key cryptographic works from this article.
0xefb99d9860f4dec4cb548a...58b19a89d2e56a864427298f826a7f887
The public key is used to generate a 40 character string called your ethereum address. This is like your account number It can be used to look up your balances and receive funds.
0xc2d7cf95645d33006175b78989035c7c9061d3f9
The only two things you need to keep track of are your ethereum address (Account number) and private key (password). If youve ever used a random password generator you can think of your private key the same way. It was generated through a process that randomly selected each letter/number in a way that is so random the result is nearly guaranteed to be unique for practical purposes. This process happens directly on your computer without any need for an internet connection.
NB: this only protects your holdings if they are stored in an offline wallet that was generated, has always been, and always will be offline. This is commonly referred to as Cold Storage in the industry and is a practice used by many cryptocurrency exchanges such as Coinbase and Binance.
With this, we have all we need to create a new and unique ethereum wallet entirely offline. As described above, once you have your private key generated offline its used to create your public key which is then used to create your ethereum address.