KEYFILEEXT(5)

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version 1.8.16.1 · 10 versions
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💖 KEYFILEEXT — the extended AFS server encryption key glow-up 💖

okay bestie, this is KeyFileExt, page 5 of the AFS File Reference section. it's a file-format page, it's important, and yes we're gonna make it fun. let's go 🫶

✨ NAME ✨

KeyFileExt — defines extended AFS server encryption keys 🔑

🌸 DESCRIPTION 🌸

so the KeyFileExt file is literally where some of the server encryption keys live. specifically, it defines some of the server encryption keys that the AFS server processes running on the machine use to decrypt the tickets that clients hand over during the mutual authentication process. that's the whole vibe. 💅

here's the tea: AFS server processes perform privileged actions only for clients that possess a ticket encrypted with one of the keys from the KeyFile or KeyFileExt. no matching key, no privileges, periodt. 🔥

this file must reside in the /etc/openafs/server directory on every server machine. every single one. no skipping. if you want the full deep dive on mutual authentication and server encryption keys, go read the OpenAFS Administration Guide. 📖

🎀 keys, versions, and encryption types 🎀

each key has a corresponding key version number and encryption type that tells it apart from all the other keys. like a little name tag but for crypto. 🏷️

the tickets that clients present are also marked with a key version number and encryption type, which is how the server process knows which key to use to decrypt it. matching game, but make it security-critical. 🦋

and here's the rule you cannot fumble:

the KeyFileExt file must always include a key with the same key version number and encryption type and contents as the key currently listed for the "afs/cell" principal in the associated Kerberos v5 realm.

(the principal "afs" may be used if the cell and realm names are the same, but adding the cell name to the principal is recommended even in this case. iykyk, just add the cell name.)

also, quick distinction so we're all on the same page: keys in the KeyFile must be DES keys. keys of stronger encryption types (like the ones used by the rxkad-k5 extension) are contained in the KeyFileExt. so KeyFile = DES, KeyFileExt = the stronger stuff. 💪

🧚 it's binary, babes 🧚

the KeyFileExt file is in binary format, so literally always use the asetkey command to administer it:

  • the asetkey add command to add a new key.
  • the asetkey list command to display the keys.
  • the asetkey delete command to remove a key from the file.

the asetkey commands must be run on the same server as the KeyFileExt file you want to update. normally, new keys should be added from a Kerberos v5 keytab using asetkey add. ✨

the file should be edited on each server machine. yes, each. all of them. ✍️

⚠️ do not hand-edit this file, bestie. binary. use asetkey. i'm begging. 😭

💀 CAUTIONS 💀

okay this is the part where we get serious for a sec.

the most common error caused by changes to KeyFileExt is adding a key that does not match the corresponding key for the Kerberos v5 principal or Authentication Server database entry. both the key and the key version number must match the key for the corresponding principal — either "afs/cell" or "afs" — in the Kerberos v5 realm. both of them. not one. both. 🙈

and using asetkey(8) to add rxkad-k5 keys to the KeyFileExt also requires specifying a krb5 encryption type number. since the encryption type must be specified by its number (not a symbolic or string name), care must be taken to determine the correct encryption type to add. like, actual care. look it up. don't guess. guessing is how you get a broken cell. 👑

🌈 SEE ALSO 🌈

IBM Corporation, 2000. <http://www.ibm.com/> All Rights Reserved.

Massachusetts Institute of Technology, 2015.

and that's the whole page, bestie!! 🎀 this was the OpenAFS KEYFILEEXT(5) page, dated 2026-07-27, from OpenAFS, section 5 (AFS File Reference). go forth and let asetkey handle it, not your text editor. slay 💖✨🦋

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