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Archival of Cryptographic Keys via the Lower Control Vector Authority Instruction

IP.com Disclosure Number: IPCOM000108838D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 4 page(s) / 136K

Publishing Venue

IBM

Related People

Abraham, D: AUTHOR [+6]

Abstract

This article describes a control vector based method for archival of cryptographic keys. The method is implemented via a Lower Control Vector Authority (LCVA) instruction. The method permits an operational key (i.e., a usable system-defined cryptographic key) to be reenciphered as an archival key (i.e., a key stored in a non-usable form, but which preserves all of the original attributes of the key). The archival form of the key permits a key to be recovered, at a later time, in the event that customary reconciliation procedures or audit procedures require that one party demonstrate to another party the validity of cryptographic data based on that key. Recovery, in this case, is performed only under secure conditions, e.g.

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Archival of Cryptographic Keys via the Lower Control Vector Authority Instruction

       This article describes a control vector based method for
archival of cryptographic keys.  The method is implemented via a
Lower Control Vector Authority (LCVA) instruction.  The method
permits an operational key (i.e., a usable system-defined
cryptographic key) to be reenciphered as an archival key (i.e., a key
stored in a non-usable form, but which preserves all of the original
attributes of the key).  The archival form of the key permits a key
to be recovered, at a later time, in the event that customary
reconciliation procedures or audit procedures require that one party
demonstrate to another party the validity of cryptographic data based
on that key.  Recovery, in this case, is performed only under secure
conditions, e.g., using a recovery utility running on a dedicated
machine, such as an IBM Personal Computer operating in PC mode.

      Fig. 1 illustrates a cryptographic system consisting of a
cryptographic facility (CF) 1 with a cryptographic instruction
execution unit 2, a key storage 3, a cryptographic facility access
program (CFAP) 4, and using application programs (APPLs) 5.  The
cryptographic facility also contains key registers 6 for the storage
of keys, including a 128-bit master key KM.  The cryptographic
instruction execution unit 2 is capable of executing a set of
cryptographic instructions, one of which is a Lower Control Vector
Authority (LCVA) instruction.  Also depicted in Fig. 1 is a utility
program 8 operating at a secure offline device 7, such as an IBM
Personal Computer (PC), capable of recovering keys from archival form
and translating them back into a usable form.  The offline key
recovery process is enabled only via special authorization, such as a
physical key, a password, a secret key, or some combination thereof.

      Consider an operational key K (a key in use on the
cryptographic system) which is archived via the LCVA instruction.  In
its operational form, K is encrypted under a storage key (*KM.C)
formed as the Exclusive OR product of the master key KM and a control
vector C, where C is the control vector specifying the usage
attributes of K.  The encrypted key e*KM.C(K) is stored in Key
Storage 3 and is identified and accessed using a key identifier (key
id).  The steps in the archival process are these:
1.   An application program-initiated archive key request is issued
to CFAP at 9.  The archive key request includes a key id, which
specifies the key to be archived.
2.   In response, CFAP fetches the encrypted key from Key...