We often say that your control over the funds in the wallet depends on the ownership and control of the corresponding private key. In blockchain transactions, the private key is used to generate the necessary signature for payment currency to prove ownership of funds. The private key must always be kept confidential, because once leaked to a third party, it is equivalent to surrendering the assets protected by the private key.
The private key is not actually stored in the network, but is generated by the user and stored in a file or simple database, known as a wallet. The private key stored in the user’s wallet is completely independent and can be generated and managed by the user’s wallet software, without the need for blockchain or network connectivity. The user’s wallet address is generated by encrypting the private key with an elliptic curve to generate a public key, which in turn generates the address.