SSH Key Management for File Transfers

SSH keys are how serious SFTP automation authenticates: no passwords in scripts, no interactive prompts at 2 a.m., and — managed well — a tighter security story than passwords could ever offer. Managed badly, they become the opposite: unlabeled keys granting forgotten access years after their owners left.

This series follows keys through their entire life: what they are and why they beat passwords for automation, generating and storing them properly, controlling the server side with authorized_keys, building rotation and inventory habits, handling host keys in unattended jobs, and retiring keys cleanly when people and systems move on.

Articles in This Series

• SSH Keys Explained for File Transfer
  Key pairs in plain words — what each half does, what a fingerprint is, and why keys beat passwords for unattended transfer jobs.
• Generating and Storing SSH Keys Properly
  A generation walkthrough, the passphrase decision for automation, file permissions that SSH enforces, and where private keys should and should not live.
• Distributing and Controlling authorized_keys
  The server-side gate: per-user and service-account patterns, restriction options that limit what a key may do, and keeping the file under change control.
• SSH Key Rotation and the Key Inventory
  Why and how often to rotate honestly, building the who-has-access-where inventory, and rotating partner-facing keys without breaking their jobs.
• Host Keys and known_hosts in Automated Transfers
  The server's identity: first-connection verification, safe handling of host-key changes in scripts, and pinning practices for unattended jobs.
• Retiring Keys: Offboarding People and Systems
  The forgotten-key problem — sweeping authorized_keys, decommissioning servers and partners, and auditing for orphaned access.

Explore More Topics

This series is part of the Sysax file transfer topic library, which covers the protocols, security practices, automation techniques, and operational skills behind reliable file transfer. The library pairs well with the practical tools we build: Sysax Multi Server, a secure FTP, FTPS, SFTP, and HTTPS server for Windows, and Sysax FTP Automation, which schedules and scripts secure transfers so the routine ones run themselves.