-snip-
I am interested in other questions, for example:
1. These are the private keys of the Wallet Import Format (WIF), as
ways to encode ECDSA private key? Then why only "one address is one key"
without reservations about diaposane? Do not change the dogma, even if it is out of date?
2. Why they look like "Private Keys WIF 51 characters base58, starts with a '5'"
and "Private Keys WIF Compressed 52 characters base58, starts with a 'K' or 'L'"
and when imported into Electrum-portable, they show the "true" first keys for the address.
It’s like, the first and simple questions in my quest for “the depths of a rabbit hole”.
Sorry for off topic.
Well, it is actually the basic question.
First of all you should know that any private key is just a number from 1 up to bitcoin order. Greater numbers just repeat the address. order + 1 has the same address as 1.
order = 115792089237316195423570985008687907852837564279074904382605163141518161494337 (in dec).
order = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141 (in hex)
The number can be represented in decimal (not widely used), in binary (used by computers), in hex (used by users), or in WIF. Actually it is the same number, but represented in different bases.
Your case: number 26 (decimal), the same as 1A (in hex), or 11010 (in binary).
The private key (number) is used to receive the public key using ECDSA. So your output will be a point with x coordinate and y coordinate. Uncompressed key means that it has both coordinates and prefix 04, but compressed used only x and prefix 02/03 depends on odd/even the y coordinate (google for it, it is due to symmetry of elliptic curve).
Now WIF is a wallt import format, used to import keys to wallet software. This format includes the private key (as hex value) and information about compression (optional byte for compression keys). All this is encoded with base58. Have a look here:
https://learnmeabitcoin.com/guide/wifConverting the private key to WIF with base58 will also make a first sign '5' due to first version byte '80' for uncompressed keys, and will also make a first sign 'K'/'L' due to 1 byte longer (suffix '01') and the same first byte '80'.
Then why only "one address is one key": because for every private key you will have only one and the same public key, for every public key you will have only one address of the
same type. However as there are different bitcoin formats, you actually could have different addresses for every type. For every private key you will have 2 legacy addresses (one compressed and one uncompressed - both start with 1), one segwit address (starts with 3) and one segwit address (starts with bc1).
