Linux ssh keygen Guide

Linux ssh-keygen Guide

Complete beginner-friendly guide to ssh-keygen on Linux, covering Arch Linux, CachyOS, and other distributions including SSH key generation, key pair creation, and secure authentication.

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Table of Contents

1. ssh-keygen Basics
2. Generating Keys
3. Key Types
4. Key Management
5. Troubleshooting

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ssh-keygen Basics

Generate Key

Basic usage:

# Generate SSH key
ssh-keygen -t ed25519

# -t = type (ed25519 recommended)

With Email

Add comment:

# With email comment
ssh-keygen -t ed25519 -C "your_email@example.com"

# -C = comment

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Generating Keys

RSA Key

RSA keypair:

# Generate RSA key
ssh-keygen -t rsa -b 4096

# -t = type (RSA)
# -b = bits (4096 recommended)

ED25519 Key

ED25519 keypair:

# Generate ED25519 key (recommended)
ssh-keygen -t ed25519

# ED25519 is faster and more secure

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Key Types

Key File Location

Default location:

# Keys stored in:
~/.ssh/id_ed25519      # Private key
~/.ssh/id_ed25519.pub  # Public key

Custom Location

Custom path:

# Custom location
ssh-keygen -t ed25519 -f ~/.ssh/my_key

# -f = file (custom filename)

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Key Management

View Public Key

Show public key:

# Display public key
cat ~/.ssh/id_ed25519.pub

# Copy this to add to servers

Copy to Server

Add to server:

# Copy public key to server
ssh-copy-id user@server

# Or manually:
cat ~/.ssh/id_ed25519.pub | ssh user@server "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

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Troubleshooting

Permission Errors

Fix permissions:

# Set correct permissions
chmod 700 ~/.ssh
chmod 600 ~/.ssh/id_ed25519
chmod 644 ~/.ssh/id_ed25519.pub

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Summary

This guide covered ssh-keygen usage, SSH key generation, and key management for Arch Linux, CachyOS, and other distributions.

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Next Steps

• SSH Configuration - SSH setup
• ssh-agent Guide - Key agent
• Security Configuration - Security setup
• ssh-keygen Documentation: man ssh-keygen

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This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.