Firstly, the private key is essentially a truly random number. Stored as a byte array in the computer. The private key of EOS is different from Ethereum, but it's more similar to Bitcoin. However, there are some differences between the EOS private key and Bitcoin.
The Ethereum private key is a hash of random numbers so that the Ethereum private key is a hexadecimal with 64 strings. Bitcoin is a WIF (Wallet Import Format) encoding format.
In fact, in Ethereum and Bitcoin, the private key has two main roles:
1. The private key generates the public key, thus deriving the transaction address
2. Authorize the transaction
But for EOS, the private key is used to generate transaction signatures, not to generate transaction addresses. Because EOS introduces the concept of an account, the EOS account is similar to the ENS domain, so the EOS transaction address is not derived from the private key.
Here take an example of the EOS private key:
Note: The first string of the private key in WIF format starts with "5", "K" or "L"
Base 58 encode