On 7/31/2014 10:18 AM, Brandon Allbery wrote: > On Thu, 2014-07-31 at 16:12 +0200, Martin Richter wrote: >> So this means that client caching can't be used anymore after DES has >> been removed from the KDC? > > No; rxkad-kdf derives a DES key from a stronger key. Also clients still > default to no encryption in the cache manager (fs setcrypt).
This is only true for UNIX cache managers. Windows default to "fs setcrypt on". > Just > pointing out that (weaker-than-)DES is still used in some places, Weaker than DES (the fcrypt encryption algorithm or no encryption at all) is used in *all* places. The use of AES256-SHA1 is only for Kerberos authentication and protection of the long term AFS service principal key. AES256 is never used for wire privacy or integrity protection within the AFS protocol. However, I believe Martin is asking a different question. When the issuance of service tickets with DES session keys is turned off in the KDC, can existing AFS cache managers that do not support "rxkad-kdf" continue to access the AFS cell? The answer to this question is "no". If an older AFS client, say OpenAFS 1.4.11 or 1.6.3 attempts to obtain an AFS token it will request the use of DES for the session key. The KDC (if DES is disabled) will either fail the request indicating that there is no support for the DES-CBC-CRC encryption type or will issue a service ticket with a non-DES session key and a failure will be reported by the client-side Kerberos library. In either case, the older AFS client will be unable to authenticate to the cell. Jeffrey Altman
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