You understood the private key, public address and sign message totally inaccurate.
I do not see your corrections as corrections, except the last mistake that I wanted to write all but changed to altcoins which I will still discuss below. You should read carefully before making comment, private key is needed to sign a message, but it will not be included while signing the message it works underneath, only what are included is the address and the message you want to sign.
In order to sign a bitcoin message, you need to have a private key for a public address from which you want to sign a message. In a reverse way, the sign message is to show you are the owner of that address by owning its private key.
Check what I posted.
Yes that is true that private key is needed to sign a message
It will require you to enter a password of your wallet. This step is mandatory if you encrypted your wallet. It is a prevention to not allow hacker to be freely sign any message when he find your bitcoin wallet file.
Not password but passphrase, know that passwords are not passphrase. It is not also an encryption but a seed extension. You are very wrong.
Not all wallets sign a message, not all private keys wallets also sign a message, there are few ones that do it, like electrum and coinomi.
It is not correct (but I don't use Coinomi so I don't know about the wallet). To sign a message, you need a wallet software that support the sign/ verify message feature. The incorrectness is from
not all private keys wallets also sign a message, you can import that private key to other wallet softwares to sign a message.
Try to correct when appropriate, what are you talking about? You mean all private key wallet sign a message? What about the private key wallets that do not have the software to sign a message like atomic wallet and many other wallets, only few private key wallets sign a message. You not correct what is right.
Say not all private key can sign a message, it is totally not correct.
Can atomic wallet sign a message, is it not a private key wallet, you need to understand about wallet before commenting about them because you are absolutely wrong and saying someone is wrong.
All wallets signing a message are altcoins private key wallets while not all private key wallets can sign a message, only few ones do it.
Why altcoins?
Corrected, typo error.
All wallets signing a message are
altcoins all private key wallets while not all private key wallets can sign a message, only few ones do it.