Mac from Terminal
ssh-keygen -t ed25519 -C "yourmail@domain.com"
output:
Generating public/private ed25519 key pair.
Enter file in which to save the key (/Users/<xxxxx>/.ssh/<yyyy>): /Users/<xxxxx>/.ssh/github_id
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/<xxxxx>/.ssh/github_id
Your public key has been saved in /Users/<xxxxx>/.ssh/github_id.pub
The key fingerprint is:
.....
The key's randomart image is:
+--[ED25519 256]--+
| .. .=.. |
| .o ..S.. |
| .. ..o. . .|
| . o. ..o . . o |
| =+...S = . + |
| oS.++ o + . |
| o+.+ . o |
| o.. . . |
| o..E |
+----[SHA256]-----+go to https://github.com/settings/keys
click to New SSH Key
write a title, select Authentication Key, copy content of <yyyy>.pub file to the Key area