1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
|
Network Working Group C. Wallace
Request for Comments: 4810 Cygnacom Solutions
Category: Informational U. Pordesch
Fraunhofer Gesellschaft
R. Brandner
InterComponentWare AG
March 2007
Long-Term Archive Service Requirements
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
There are many scenarios in which users must be able to prove the
existence of data at a specific point in time and be able to
demonstrate the integrity of data since that time, even when the
duration from time of existence to time of demonstration spans a
large period of time. Additionally, users must be able to verify
signatures on digitally signed data many years after the generation
of the signature. This document describes a class of long-term
archive services to support such scenarios and the technical
requirements for interacting with such services.
Wallace, et al. Informational [Page 1]
^L
RFC 4810 Archive Requirements March 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General Principles . . . . . . . . . . . . . . . . . . . . . . 5
4. Technical Requirements . . . . . . . . . . . . . . . . . . . . 6
4.1. Enable Submission, Retrieval, and Deletion of Archived
Data Objects . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.1. Functional Requirements . . . . . . . . . . . . . . . 7
4.1.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Operate in accordance with a long-term archive policy . . 8
4.2.1. Functional Requirements . . . . . . . . . . . . . . . 8
4.2.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 9
4.3. Enable Management of Archived Data Objects . . . . . . . . 9
4.3.1. Functional Requirements . . . . . . . . . . . . . . . 9
4.3.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 9
4.4. Provide Evidence Records that Support Demonstration of
Data Integrity . . . . . . . . . . . . . . . . . . . . . . 10
4.4.1. Functional Requirements . . . . . . . . . . . . . . . 10
4.4.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 10
4.5. Support Data Confidentiality . . . . . . . . . . . . . . . 11
4.5.1. Functional Requirements . . . . . . . . . . . . . . . 11
4.5.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 11
4.6. Provide Means to Transfer Data and Evidence from One
Service to Another . . . . . . . . . . . . . . . . . . . . 11
4.6.1. Functional Requirements . . . . . . . . . . . . . . . 11
4.6.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 11
4.7. Support Operations on Groups of Data Objects . . . . . . . 12
4.7.1. Functional Requirements . . . . . . . . . . . . . . . 12
4.7.2. Rationale . . . . . . . . . . . . . . . . . . . . . . 12
5. Operational Considerations . . . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
8. Informative References . . . . . . . . . . . . . . . . . . . . 14
Appendix A. Application Scenarios . . . . . . . . . . . . . . . . 15
A.1. Archive Service Supporting Long-Term Non-Repudiation . . . 15
A.2. Pure Long-Term Non-Repudiation Service . . . . . . . . . . 15
A.3. Long-Term Archive Service as Part of an Internal
Network . . . . . . . . . . . . . . . . . . . . . . . . . 15
A.4. Long-Term Archive External Service . . . . . . . . . . . . 15
Wallace, et al. Informational [Page 2]
^L
RFC 4810 Archive Requirements March 2007
1. Introduction
Digital data durability is undermined by continual progress and
change on a number of fronts. The useful lifetime of data may exceed
the life span of formats and mechanisms used to store the data. The
lifetime of digitally signed data may exceed the validity periods of
public-key certificates used to verify signatures or the
cryptanalysis period of the cryptographic algorithms used to generate
the signatures, i.e., the time after which an algorithm no longer
provides the intended security properties. Technical and operational
means are required to mitigate these issues. A solution must address
issues such as storage media lifetime, disaster planning, advances in
cryptanalysis or computational capabilities, changes in software
technology, and legal issues.
A long-term archive service aids in the preservation of data over
long periods of time through a regimen of technical and procedural
mechanisms designed to support claims regarding a data object. For
example, it might periodically perform activities to preserve data
integrity and the non-repudiability of data existence by a particular
point in time or take actions to ensure the availability of data.
Examples of periodic activities include refreshing time stamps or
transferring data to a new storage medium.
A long-term archive service may be used to provide evidence that
supports validation of the existence of documents or assertions of
agreements that were originally asserted with digital signatures.
Validation may occur at times in the future well beyond the validity
period of the private key originally used to generate the signature,
or even beyond the time when the algorithms available for digital
signatures, message digesting, or data encryption cease to offer
effective protection because of improvements in computing speeds and
methods.
A long-term archive service may be located within an enterprise
network, communicating with local storage mechanisms and other
applications, or a long-term archive service may be implemented as an
external service accessible via the Internet. A long-term archive
service may use functionality, e.g., time stamping, provided by
independent service providers.
A primary goal of a long-term archive service is to support the
credible assertion of a claim that is currently asserted, at points
well into the future. A long-term archive service may support a
range of applications, including: wills, land records, medical data,
criminal case files, personnel files, and contracts. A long-term
archive service may be used by any type of entity, e.g.,
Wallace, et al. Informational [Page 3]
^L
RFC 4810 Archive Requirements March 2007
organizations, citizens, notaries. Examples of long-term archive
service usage by submitters include:
- A company stores contracts using a third party service.
- A hospital stores medical data using an internal service.
- An individual wants to generate evidence of data possession at a
particular point in time, e.g., for intellectual property purposes
or endorsement of a contract.
- A law enforcement officer wants to store criminal data such that
integrity of the data can be demonstrated years later.
For each of the above examples, there is a corresponding example
involving retrievers, e.g., a company retrieves a contract in the
case of a dispute or a law enforcement officer prepares information
for a criminal trial.
This document addresses the technical requirements for a long-term
archive service.
2. Terminology
We define the following terms based on their usage in the archiving
community, in order to provide a vocabulary for describing
requirements and the standards around them.
Arbitrator: Principal for whom the validity of archived data
characteristics, e.g., origin, integrity or time of existence,
must be demonstrated.
Archival Period: The period during which an archived data object is
preserved by a long-term archive service.
Archived Data Object: Data unit to be preserved by a long-term
archive service.
Archive Package: Collection of information including archived data
objects and associated Evidence Record.
Cryptographic Maintenance Policy: A set of rules that defines how
to maintain the validity of digitally signed objects should one of
the hash or asymmetric algorithms used to create a digital
signature become weak, or one of the private keys used to create a
digital signature be compromised or become weak.
Wallace, et al. Informational [Page 4]
^L
RFC 4810 Archive Requirements March 2007
Evidence: Information that may be used to demonstrate the validity
of an archived data object or related attestations.
Evidence Record: Collection of evidence compiled for one or more
archived data objects. An Evidence Record may include
acknowledgements from a long-term archive service, time stamps and
verification data, such as public-key certificates, revocation
information, trust anchors, policy details and role information.
Long-Term Archive Policy: A set of rules that define operational
characteristics of a long-term archive service.
Long-Term Archive Service (LTA): A service that is responsible for
preserving data for long periods.
Modifier: Principal who modifies attributes associated with an
archived data object and/or Evidence Record held by a long-term
archive service.
Originator: Principal who produces, and possibly digitally signs,
an archived data object. The Originator does not necessarily have
any relationship with a long-term archive service or any awareness
of an Evidence Record associated with the archived data object.
Retriever: Principal who retrieves archived data objects and/or
Evidence Records from a long-term archive service.
Submitter: Principal who submits data objects for archiving.
Time Stamp: An attestation generated by a Time Stamping Authority
(TSA) that a data item existed at a certain time. For example,
[RFC3161] specifies a structure for signed time stamp tokens as
part of a protocol for communicating with a TSA.
Time Stamping Authority (TSA): A trusted service that provides
attestations of existence of data at particular points in time.
For example, [RFC3161] defines protocol elements for interacting
with a TSA.
3. General Principles
A long-term archive service may accept any type of data for
preservation. The data might be in any format, whether textual data,
images, documents, applications, or compound packages of multiple
components. The data may be digitally signed, time stamped,
encrypted, or not subject to any cryptographic processing.
Wallace, et al. Informational [Page 5]
^L
RFC 4810 Archive Requirements March 2007
A long-term archive service may preserve archived data objects as
opaque collections of bytes with the primary aim of data integrity.
A long-term archive service is not required to operate upon evidence
related to the content of archived data objects. Content-focused
operations, including data format migration or translation, may be
performed by another service. However, an LTA may incorporate
support for such services.
Different long-term archive services may establish policies and
procedures for archiving data objects over different lengths of time.
For example, an LTA may refuse to preserve archived data objects for
periods longer than 30 years. Similarly, LTAs may establish policies
that limit the types of data that will be accepted for deposit by a
particular LTA.
A long-term archive service provides evidence that may be used to
demonstrate the existence of an archived data object at a given time
and the integrity of the archived data object since that time.
Additionally, the evidence identifies the LTA(s) that have
participated in the preservation of the archived data object. If the
archived data object itself contains digitally signed data,
authentication of the signer is also possible.
A long-term archive service may be an adjunct component of a document
management system. In such cases, the Evidence Record generated and
maintained by the LTA is a property of data that is otherwise managed
by the document management system.
4. Technical Requirements
This section describes the requirements for the protocol for
accessing a long-term archive system and for the data formats
associated with data preservation.
4.1. Enable Submission, Retrieval, and Deletion of Archived Data
Objects
Wallace, et al. Informational [Page 6]
^L
RFC 4810 Archive Requirements March 2007
4.1.1. Functional Requirements
A long-term archive service must permit clients to request the
following basic operations:
- submit data objects for archive
- retrieve archived data objects
- delete archived data objects
Following submission, the service must provide an identifier that can
be used to retrieve the archived data and/or associated evidence.
For example, it may be possible to retrieve archive packages by using
a hash value of an archived data object. Possession of this value is
not necessarily an authorization to access the associated archived
data object or evidence record.
It must be possible to authenticate requests and responses, e.g., to
enable LTAs to render an authorization decision. This may be
accomplished by using transport security mechanisms. Requests, in
particular retrieval or deletion requests, may be rejected if the
requestor is not authorized. An authorization policy must be defined
and observed by the long-term archive service. An LTA may disallow
deletion as a matter of policy.
The format for the acknowledgements must allow the identification of
the archiving provider and the participating client.
The LTA must provide an acknowledgement of the deposit that permits
the submitter to confirm the correct data was accepted by the LTA.
This proof need not be provided immediately.
4.1.2. Rationale
Submission, retrieval, query state, and deletion of archived data
objects are necessary basic functions of a long-term archive service.
Deletion may be disallowed due to procedural difficulties in
fulfilling the request. For example, an archived data object may be
stored on write-once media, along with other records that are not
subject to deletion.
Acknowledgements may not be provided immediately due to
implementation of a grace period. A generic query state mechanism
should be provided to address such situations. For example, a
Wallace, et al. Informational [Page 7]
^L
RFC 4810 Archive Requirements March 2007
submission response may indicate that a submission has been accepted
and a subsequent query state response may indicate a submission has
completed all necessary preservation steps.
4.2. Operate in accordance with a long-term archive policy
4.2.1. Functional Requirements
A long-term archive service must operate in accordance with a long-
term archive service policy that defines characteristics of the
implementation of the long-term archive service. A long-term archive
service policy contains several components, including:
- Archived data object maintenance policy
- Authorization policy
- Service policy
A long-term archive service policy must include specifications of the
preservation activities performed for archived data objects subject
to the policy. A maintenance policy should define rules for the
following operational aspects: preservation activity triggers,
default archival period, and default handling upon expiration of
archival period.
Maintenance policies should include mechanism-specific details
describing LTA operation. For example, where cryptographic
mechanisms are employed, a cryptographic maintenance policy ought to
be defined.
An authorization policy should define the entities permitted to
exercise services provided by the LTA, including who is permitted to
submit, retrieve, or manage specific archived data objects.
A service policy defines the types of services provided by an LTA,
including acceptable data types, description of requests that may be
accepted, and deletion procedures.
Policies must be unambiguously identified, e.g., by an object
identifier. Alternatively, an LTA may support a protocol that
permits clients to specify policy parameters explicitly instead of by
reference to a policy.
A long-term archive service must be able to provide information
identifying the policies relevant for a given archived data object.
Wallace, et al. Informational [Page 8]
^L
RFC 4810 Archive Requirements March 2007
4.2.2. Rationale
Similar to a certificate policies [RFC3647], which are identified
using object identifiers, a long-term archive policy provides a
shorthand means of technically identifying a set of rules that govern
the operation of a long-term archive service.
Over the course of many years, the policies under which an LTA
operates may undergo modification. Thus, an evidence record may
feature multiple indications of policies active at various points
during the life of an archived data object.
4.3. Enable Management of Archived Data Objects
4.3.1. Functional Requirements
A long-term archive service must permit clients to request the
following basic operations:
- specify an archival period for submitted data objects
- extend or shorten the archival period for an archived data object
- specify metadata associated with an archived data object
- specify an archive policy under which the submitted data should be
handled
It should be possible to express an archival period in terms of time,
an event or a combination of time and event.
Submitters should be able to specify metadata that, for example, can
be used to enable retrievers to render the data correctly, to locate
data in an archive or to place data in a particular context.
Examples include, classification codes, type of format, contributors,
title, author, and date. Alternatively, such information may be
included in the content of an archived data object.
If a long-term archive service does not support a requested policy,
it must return an error indication. A service must provide an
indication of the archive policy enforced by the service.
4.3.2. Rationale
Submission, retrieval, and deletion of archived data objects are
necessary basic functions of a long-term archive service.
Wallace, et al. Informational [Page 9]
^L
RFC 4810 Archive Requirements March 2007
Specification and management of the archival period is necessary to
avoid unnecessary preservation activities.
4.4. Provide Evidence Records that Support Demonstration of Data
Integrity
4.4.1. Functional Requirements
A long-term archive service must be capable of providing evidence
that can be used to demonstrate the integrity of data for which it is
responsible, from the time it received the data until the expiration
of the archival period of the data.
This may be achieved by providing evidence records that support the
long-term non-repudiation of data existence at a point in time, e.g.,
in the case of legal disputes. The evidence record should contain
sufficient information to enable the validity of an archived data
object's characteristics to be demonstrated to an arbitrator. The
characteristics subject to verification will vary. For example,
authentication of an originator may not be possible in all cases,
e.g., where the object submitted to the archive is not signed or
where the object does not include the necessary information to
authenticate the object's signer.
Evidence records must be structured such that modifications to an
archived data object or its evidence record can be detected,
including modifications made by administrators of an LTA.
4.4.2. Rationale
Supporting non-repudiation of data existence, integrity, and origin
is a primary purpose of a long-term archive service. Evidence may be
generated, or otherwise obtained, by the service providing the
evidence to a retriever. A long-term archive service need not be
capable of providing all evidence necessary to produce a non-
repudiation proof, and in some cases, should not be trusted to
provide all necessary information. For example, trust anchors
[RFC3280] and algorithm security policies should be provided by other
services. An LTA that is trusted to provide trust anchors could
forge an evidence record verified by using those trust anchors.
Demonstration that data has not been altered while in the care of a
long-term archive service is a first step towards supporting non-
repudiation of data. Certification services support cases in which
data must be modified, e.g., translation or format migration. An LTA
may provide certification services.
Wallace, et al. Informational [Page 10]
^L
RFC 4810 Archive Requirements March 2007
4.5. Support Data Confidentiality
4.5.1. Functional Requirements
A long-term archive service must provide means to ensure
confidentiality of archived data objects, including confidentiality
between the submitter and the long-term archive service. An LTA must
provide a means for accepting encrypted data such that future
preservation activities apply to the original, unencrypted data.
Encryption, or other methods of providing confidentiality, must not
pose a risk to the associated evidence record.
A long-term archive service should maintain contact information for
the parties responsible for each archived data object so warning
messages can be sent when encryption algorithms require maintenance.
4.5.2. Rationale
Individuals may wish to use the services of a commercial long-term
service without disclosing data to the commercial service. However,
access to the original data may be necessary to perform some
preservation activities.
4.6. Provide Means to Transfer Data and Evidence from One Service to
Another
4.6.1. Functional Requirements
It must be possible to submit data along with previously generated
evidence, i.e., to support transfer of data from one archive to
another. A long-term archive service must support the transfer of
archived data objects, evidence and evidence records from one service
to another. It must be possible for evidence records to span
multiple providers over the course of time, without losing value as
evidence.
4.6.2. Rationale
Before the end of an archived data object's archival period, a long-
term archive service may cease operation. In such cases, it must be
possible for the archived data object (and any associated evidence)
to be transferred to another service that will continue preservation
of the data until the end of the archival period.
Submitters may change service providers before the end of an archived
data object's archival period. In such cases, it must be possible
for the submitter to transfer an archived data object and all
associated evidence from the original LTA to a new LTA.
Wallace, et al. Informational [Page 11]
^L
RFC 4810 Archive Requirements March 2007
4.7. Support Operations on Groups of Data Objects
4.7.1. Functional Requirements
An LTA should support submission of groups of data objects.
Submitters should be able to indicate which data objects belong
together, i.e. comprise a group, and retrievers should be able to
retrieve one, some or all members of a group of data objects.
It should be possible to provide evidence for groups of archived data
objects. For example, it should be possible to archive a document
file and a signature file together such that they are covered by the
same evidence record.
Where an LTA operates upon groups of data objects, non-repudiation
proof must still be available for each archived data object
separately.
4.7.2. Rationale
In many cases data objects belong together. Examples include:
- a document file and an associated signature file, which are two
separate objects
- TIF-files representing pages of a document
- a document file and an evidence file (possibly generated by
another LTA)
- a document and its translation to another format or language
In these cases, it is to the best advantage to handle these data
objects as a group.
5. Operational Considerations
A long-term archive service must be able to work efficiently even for
large amounts of archived data objects. In order to limit expenses
and to achieve high performance, it may be desirable to minimize the
use of trusted third parties, e.g., LTA operations should be designed
to limit the number of time stamps required to provide the desired
level of service.
Necessity to access archived data objects should be minimized. It
may only be necessary to access the archived data objects if the
archived data objects are requested by users, or if hash algorithms
used for indexing, or evidence record generation become insecure.
Wallace, et al. Informational [Page 12]
^L
RFC 4810 Archive Requirements March 2007
An LTA must be capable of operating in accordance with any applicable
legal regime. For example, an LTA may be required to reject a
deletion request from an authorized requestor if the target of the
request has been subpoenaed by law enforcement authorities.
Some applications may require processing of a chain of archive
policies present in an evidence record, e.g., to ensure that
compatible policies were used throughout the lifetime of the archived
data objects.
6. Security Considerations
Data is the principal asset protected by a long-term archive service.
The principle threat that must be addressed by a long-term archive
service is an undetected loss of data integrity.
In cases where signature verification relies on a PKI, certificate
revocation could retroactively invalidate previously verified
signatures. An LTA may implement measures to support such claims by
an alleged signer, e.g., collection of revocation information after a
grace period during which compromise can be reported or preservation
of subsequent revocation information.
When selecting access control mechanisms associated with data stored
by a LTA, the lifespan of the archived data object should be
considered. For example, the credentials of an entity that submitted
data to an archive may not be available or valid when the data needs
to be retrieved.
During the lifespan of an archived data object, formats may cease to
be supported. Software components to process data, including content
or signatures, may no longer be available. This could be a problem
particularly if non-standard formats are used or proprietary
processing is employed. The submitter should take care to avoid such
problems. For example, the submitter (or other authorized entity)
could periodically retrieve data, convert the data, and re-submit it
in a new format. Additional mechanisms, applications, or tools may
be needed to preserve the value of evidence records associated with
the original archived data object.
A long-term archive system may require correlation of different
identities that represent the same entity at different points in
time. For example, an individual's identity may be represented by
different employers at different points in time.
A long-term archive system must perform maintenance activities on a
schedule that considers factors such as the strength of relevant
cryptographic algorithms, lifespan of relevant certification
Wallace, et al. Informational [Page 13]
^L
RFC 4810 Archive Requirements March 2007
authorities, and revocation status of relevant entities, e.g.,
timestamp authorities. Standards for use of cryptographic algorithms
are expected to be established by organization or governmental
bodies, not by individual LTAs.
7. Acknowledgements
Thanks to members of the LTANS mailing list for review of earlier
drafts and many suggestions. In particular, thanks to Larry
Masinter, Denis Pinkas, and Peter Sylvester for review and
suggestions.
8. Informative References
[RFC3161] Adams, C., Cain, P., Pinkas, D., and R. Zuccherato,
"Internet X.509 Public Key Infrastructure Time-Stamp
Protocol (TSP)", RFC 3161, August 2001.
[RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 3280,
April 2002.
[RFC3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and S.
Wu, "Internet X.509 Public Key Infrastructure Certificate
Policy and Certification Practices Framework", RFC 3647,
November 2003.
Wallace, et al. Informational [Page 14]
^L
RFC 4810 Archive Requirements March 2007
Appendix A. Application Scenarios
Below are several example application scenarios demonstrating one or
more of the basic service features mentioned above.
A.1. Archive Service Supporting Long-Term Non-Repudiation
A long-term archive service may store data objects, such as signed or
unsigned documents, for authenticated users. It may generate time
stamps for these data objects and obtain verification data during the
archival period or until a deletion request is received from an
authorized entity.
A.2. Pure Long-Term Non-Repudiation Service
A long-term archive service may only guarantee non-repudiation of
existence of data by periodically generating time stamps and
obtaining verification data. It stores data objects (e.g., documents
and signatures) locally only for the purpose of non-repudiation and
does not function as a document archive for users. It does not
support retrieval and deletion of data objects.
A.3. Long-Term Archive Service as Part of an Internal Network
A long-term archive service may be part of an enterprise network.
The network provider and archive service may be part of the same
institution. In this case, the service should obtain non-repudiation
evidence from a third party. An internally generated acknowledgement
may be viewed worthless.
A.4. Long-Term Archive External Service
A long-term archive service may be provided over the Internet for
enterprises or consumers. In this case, archiving and providing
evidence (via time stamps or other means) may be adduced by one
organization and its own technical infrastructure, without using
external services.
Wallace, et al. Informational [Page 15]
^L
RFC 4810 Archive Requirements March 2007
Authors' Addresses
Carl Wallace
Cygnacom Solutions
Suite 5200
7925 Jones Branch Drive
McLean, VA 22102
Fax: +1(703)848-0960
EMail: cwallace@cygnacom.com
Ulrich Pordesch
Fraunhofer Gesellschaft
Rheinstrasse 75
Darmstadt, Germany D-64295
EMail: ulrich.pordesch@zv.fraunhofer.de
Ralf Brandner
InterComponentWare AG
Otto-Hahn-Strabe 3
Walldorf, Germany 69190
EMail: ralf.brandner@intercomponentware.com
Wallace, et al. Informational [Page 16]
^L
RFC 4810 Archive Requirements March 2007
Full Copyright Statement
Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Wallace, et al. Informational [Page 17]
^L
|