Try: ssh-keygen -t ed25519 -a 100 -f ~/.ssh/id_ed25519 -C "linuxteck@ubuntu-2026"
Info:Ed25519 provides faster, more secure keys than RSA. -a 100 increases KDF rounds to strengthen passphrase protection against offline brute-forcing.
Examples:
$ ssh-copy-id -i ~/.ssh/id_ed25519.pub user@server # Copy public key to server
$ ssh-keygen -y -f ~/.ssh/id_ed25519 # Print public key from private key
$ ssh-keygen -lf ~/.ssh/id_ed25519.pub # View key fingerprint and bit length
Note:RSA needs 4096 bits to match Ed25519 (256-bit) security. Ed25519 is the modern OpenSSH default. Use RSA only if connecting to legacy systems.
LinuxTeck.com
linuxteck@ubuntu:~$ ssh-keygen -t ed25519 -a 100 -f ~/.ssh/id_ed25519 -C "linuxteck@ubuntu-2026"
Generating public/private ed25519 key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/linuxteck/.ssh/id_ed25519
Your public key has been saved in /home/linuxteck/.ssh/id_ed25519.pub
The key fingerprint is:
SHA256:4x8K9mPz2L1QR3sT6uW9yA5bC8dE1fG4hI7jK0lM2 linuxteck@ubuntu-2026
linuxteck@ubuntu:~$
John Britto Founder & Chief-Editor @LinuxTeck. A Computer Geek and Linux Intellectual having more than 20+ years of experience in Linux and Open Source technologies.
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