[2160] in Kerberos_V5_Development
Re: krb5_mk_priv keeps a replay cache
daemon@ATHENA.MIT.EDU (Theodore Y. Ts'o)
Fri Jan 3 18:43:19 1997
Date: Fri, 3 Jan 1997 18:43:11 -0500
From: "Theodore Y. Ts'o" <tytso@MIT.EDU>
To: Marc Horowitz <marc@cygnus.com>
Cc: "Theodore Y. Ts'o" <tytso@MIT.EDU>, krbdev@MIT.EDU
In-Reply-To: Marc Horowitz's message of 03 Jan 1997 16:06:48 -0500,
<t53d8vmo4d3.fsf@rover.cygnus.com>
From: Marc Horowitz <marc@cygnus.com>
Date: 03 Jan 1997 16:06:48 -0500
>> From: Marc Horowitz <marc@cygnus.com>
>> Date: 02 Jan 1997 18:05:15 -0500
>>
>> Is there a reason for this, or should be code be shot and killed at
>> dawn?
>>
>> The KRB5_AP_PRIV message can protect against replay using either a
>> sequence number, or using a timestamp. If you're using a timestamp, you
>> need the replay cache as well to provide full protection against
>> replays.
This is a rational argument for maintaining a replay cache in
krb5_rd_priv, but why keep a cache in krb5_mk_priv?
To prevent an attacker from taking a message you generating using
krb5_mk_priv, and sending it back at you.
- Ted
