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
|
@node Included programs
@chapter Included programs
Included with @acronym{GnuTLS} are also a few command line tools that
let you use the library for common tasks without writing an
application. The applications are discussed in this chapter.
@menu
* Invoking certtool::
* Invoking gnutls-cli::
* Invoking gnutls-cli-debug::
* Invoking gnutls-serv::
* Invoking psktool::
* Invoking srptool::
* Invoking p11tool::
@end menu
@node Invoking certtool
@section Invoking certtool
@cindex certtool
This is a program to generate @acronym{X.509} certificates, certificate
requests, CRLs and private keys.
@example
Certtool help
Usage: certtool [options]
-s, --generate-self-signed
Generate a self-signed certificate.
-c, --generate-certificate
Generate a signed certificate.
--generate-proxy Generate a proxy certificate.
--generate-crl Generate a CRL.
-u, --update-certificate
Update a signed certificate.
-p, --generate-privkey Generate a private key.
-q, --generate-request Generate a PKCS #10 certificate
request.
-e, --verify-chain Verify a PEM encoded certificate chain.
The last certificate in the chain must
be a self signed one.
--verify Verify a PEM encoded certificate chain.
CA certificates must be loaded with
--load-ca-certificate.
--verify-crl Verify a CRL.
--generate-dh-params Generate PKCS #3 encoded Diffie-Hellman
parameters.
--get-dh-params Get the included PKCS #3 encoded
Diffie-Hellman parameters.
--load-privkey FILE Private key file to use.
--load-pubkey FILE Public key file to use.
--load-request FILE Certificate request file to use.
--load-certificate FILE
Certificate file to use.
--load-ca-privkey FILE Certificate authority's private key
file to use.
--load-ca-certificate FILE
Certificate authority's certificate
file to use.
--password PASSWORD Password to use.
-i, --certificate-info Print information on a certificate.
--certificate-pubkey Print certificate public key.
--pgp-certificate-info Print information on a OpenPGP
certificate.
--pgp-ring-info Print information on a keyring
structure.
-l, --crl-info Print information on a CRL.
--crq-info Print information on a Certificate
Request.
--no-crq-extensions Do not use extensions in certificate
requests.
--p12-info Print information on a PKCS #12
structure.
--p7-info Print information on a PKCS #7
structure.
--smime-to-p7 Convert S/MIME to PKCS #7 structure.
-k, --key-info Print information on a private key.
--pgp-key-info Print information on a OpenPGP private
key.
--pubkey-info Print information on a public key.
--fix-key Regenerate the parameters in a private
key.
--v1 Generate an X.509 version 1 certificate
(no extensions).
--to-p12 Generate a PKCS #12 structure.
--to-p8 Generate a PKCS #8 key structure.
-8, --pkcs8 Use PKCS #8 format for private keys.
--dsa Use DSA keys.
--ecc Use ECC (ECDSA) keys.
--hash STR Hash algorithm to use for signing
(MD5,SHA1,RMD160,SHA256,SHA384,SHA512).
--export-ciphers Use weak encryption algorithms.
--inder Use DER format for input certificates
and private keys.
--inraw Use RAW/DER format for input
certificates and private keys.
--outder Use DER format for output certificates
and private keys.
--outraw Use RAW/DER format for output
certificates and private keys.
--bits BITS specify the number of bits for key
generation.
--sec-param PARAM specify the security level
[low|normal|high|ultra].
--disable-quick-random Use /dev/random for key generationg,
thus increasing the quality of
randomness used.
--outfile FILE Output file.
--infile FILE Input file.
--template FILE Template file to use for non
interactive operation.
--pkcs-cipher CIPHER Cipher to use for pkcs operations
(3des,3des-pkcs12,aes-128,aes-192,aes-25
6,rc2-40,arcfour).
-d, --debug LEVEL specify the debug level. Default is 1.
-h, --help shows this help text
-v, --version shows the program's version
@end example
The program can be used interactively or non interactively by
specifying the @code{--template} command line option. See below for an
example of a template file.
@subsection Diffie-Hellman parameter generation
To generate parameters for Diffie-Hellman key exchange, use the command:
@smallexample
$ certtool --generate-dh-params --outfile dh.pem
@end smallexample
@subsection Self-signed certificate generation
To create a self signed certificate, use the command:
@smallexample
$ certtool --generate-privkey --outfile ca-key.pem
$ certtool --generate-self-signed --load-privkey ca-key.pem \
--outfile ca-cert.pem
@end smallexample
Note that a self-signed certificate usually belongs to a certificate
authority, that signs other certificates.
@subsection Private key generation
To create a private key (RSA by default), run:
@smallexample
$ certtool --generate-privkey --outfile key.pem
@end smallexample
To create a DSA or elliptic curves (ECDSA) private key use the
above command combined with @code{--dsa} or @code{--ecc} options.
@subsection Certificate generation
To generate a certificate using the private key, use the command:
@smallexample
$ certtool --generate-certificate --load-privkey key.pem \
--outfile cert.pem --load-ca-certificate ca-cert.pem \
--load-ca-privkey ca-key.pem
@end smallexample
Alternatively you may create a certificate request, which is needed
when the certificate will be signed by a third party authority.
@smallexample
$ certtool --generate-request --load-privkey key.pem \
--outfile request.pem
@end smallexample
If the private key is stored in a smart card you can generate
a request by specifying the private key object URL (see @ref{Invoking p11tool}
on how to obtain the URL).
@smallexample
$ certtool --generate-request --load-privkey pkcs11:(PRIVKEY URL) \
--load-pubkey pkcs11:(PUBKEY URL) --outfile request.pem
@end smallexample
To generate a certificate using the previous request, use the command:
@smallexample
$ certtool --generate-certificate --load-request request.pem \
--outfile cert.pem \
--load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem
@end smallexample
@subsection Certificate information
To view the certificate information, use:
@smallexample
$ certtool --certificate-info --infile cert.pem
@end smallexample
@subsection @acronym{PKCS} #12 structure generation
To generate a @acronym{PKCS} #12 structure using the previous key and
certificate, use the command:
@smallexample
$ certtool --load-certificate cert.pem --load-privkey key.pem \
--to-p12 --outder --outfile key.p12
@end smallexample
Some tools (reportedly web browsers) have problems with that file
because it does not contain the CA certificate for the certificate.
To work around that problem in the tool, you can use the
--load-ca-certificate parameter as follows:
@smallexample
$ certtool --load-ca-certificate ca.pem \
--load-certificate cert.pem --load-privkey key.pem \
--to-p12 --outder --outfile key.p12
@end smallexample
@subsection Proxy certificate generation
Proxy certificate can be used to delegate your credential to a
temporary, typically short-lived, certificate. To create one from the
previously created certificate, first create a temporary key and then
generate a proxy certificate for it, using the commands:
@smallexample
$ certtool --generate-privkey > proxy-key.pem
$ certtool --generate-proxy --load-ca-privkey key.pem \
--load-privkey proxy-key.pem --load-certificate cert.pem \
--outfile proxy-cert.pem
@end smallexample
@subsection Certificate revocation list generation
To create an empty Certificate Revocation List (CRL) do:
@smallexample
$ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
--load-ca-certificate x509-ca.pem
@end smallexample
To create a CRL that contains some revoked certificates, place the
certificates in a file and use @code{--load-certificate} as follows:
@smallexample
$ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
--load-ca-certificate x509-ca.pem --load-certificate revoked-certs.pem
@end smallexample
To verify a Certificate Revocation List (CRL) do:
@smallexample
$ certtool --verify-crl --load-ca-certificate x509-ca.pem < crl.pem
@end smallexample
@subsection Certtool's template file format:
A template file can be used to avoid the interactive questions of
certtool. Initially create a file named 'cert.cfg' that contains the information
about the certificate. The template can be used as below:
@smallexample
$ certtool --generate-certificate cert.pem --load-privkey key.pem \
--template cert.cfg \
--load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem
@end smallexample
An example certtool template file:
@example
# X.509 Certificate options
#
# DN options
# The organization of the subject.
organization = "Koko inc."
# The organizational unit of the subject.
unit = "sleeping dept."
# The locality of the subject.
# locality =
# The state of the certificate owner.
state = "Attiki"
# The country of the subject. Two letter code.
country = GR
# The common name of the certificate owner.
cn = "Cindy Lauper"
# A user id of the certificate owner.
#uid = "clauper"
# If the supported DN OIDs are not adequate you can set
# any OID here.
# For example set the X.520 Title and the X.520 Pseudonym
# by using OID and string pairs.
#dn_oid = "2.5.4.12" "Dr." "2.5.4.65" "jackal"
# This is deprecated and should not be used in new
# certificates.
# pkcs9_email = "none@@none.org"
# The serial number of the certificate
serial = 007
# In how many days, counting from today, this certificate will expire.
expiration_days = 700
# X.509 v3 extensions
# A dnsname in case of a WWW server.
#dns_name = "www.none.org"
#dns_name = "www.morethanone.org"
# An IP address in case of a server.
#ip_address = "192.168.1.1"
# An email in case of a person
email = "none@@none.org"
# An URL that has CRLs (certificate revocation lists)
# available. Needed in CA certificates.
#crl_dist_points = "http://www.getcrl.crl/getcrl/"
# Whether this is a CA certificate or not
#ca
# Whether this certificate will be used for a TLS client
#tls_www_client
# Whether this certificate will be used for a TLS server
#tls_www_server
# Whether this certificate will be used to sign data (needed
# in TLS DHE ciphersuites).
signing_key
# Whether this certificate will be used to encrypt data (needed
# in TLS RSA ciphersuites). Note that it is preferred to use different
# keys for encryption and signing.
#encryption_key
# Whether this key will be used to sign other certificates.
#cert_signing_key
# Whether this key will be used to sign CRLs.
#crl_signing_key
# Whether this key will be used to sign code.
#code_signing_key
# Whether this key will be used to sign OCSP data.
#ocsp_signing_key
# Whether this key will be used for time stamping.
#time_stamping_key
# Whether this key will be used for IPsec IKE operations.
#ipsec_ike_key
@end example
@node Invoking gnutls-cli
@section Invoking gnutls-cli
@cindex gnutls-cli
Simple client program to set up a TLS connection to some other
computer. It sets up a TLS connection and forwards data from the
standard input to the secured socket and vice versa.
@example
GnuTLS test client
Usage: gnutls-cli [options] hostname
-d, --debug integer Enable debugging
-r, --resume Connect, establish a session. Connect
again and resume this session.
-s, --starttls Connect, establish a plain session and
start TLS when EOF or a SIGALRM is
received.
--crlf Send CR LF instead of LF.
--x509fmtder Use DER format for certificates to read
from.
-f, --fingerprint Send the openpgp fingerprint, instead
of the key.
--disable-extensions Disable all the TLS extensions.
--print-cert Print the certificate in PEM format.
--recordsize integer The maximum record size to advertize.
-V, --verbose More verbose output.
--ciphers cipher1 cipher2...
Ciphers to enable.
--protocols protocol1 protocol2...
Protocols to enable.
--comp comp1 comp2... Compression methods to enable.
--macs mac1 mac2... MACs to enable.
--kx kx1 kx2... Key exchange methods to enable.
--ctypes certType1 certType2...
Certificate types to enable.
--priority PRIORITY STRING
Priorities string.
--x509cafile FILE Certificate file to use.
--x509crlfile FILE CRL file to use.
--pgpkeyfile FILE PGP Key file to use.
--pgpkeyring FILE PGP Key ring file to use.
--pgpcertfile FILE PGP Public Key (certificate) file to
use.
--pgpsubkey HEX|auto PGP subkey to use.
--x509keyfile FILE X.509 key file to use.
--x509certfile FILE X.509 Certificate file to use.
--srpusername NAME SRP username to use.
--srppasswd PASSWD SRP password to use.
--pskusername NAME PSK username to use.
--pskkey KEY PSK key (in hex) to use.
--opaque-prf-input DATA
Use Opaque PRF Input DATA.
-p, --port PORT The port to connect to.
--insecure Don't abort program if server
certificate can't be validated.
-l, --list Print a list of the supported
algorithms and modes.
-h, --help prints this help
-v, --version prints the program's version number
@end example
@menu
* Example client PSK connection::
@end menu
@node Example client PSK connection
@subsection Example client PSK connection
@cindex PSK client
To connect to a server using PSK authentication, you need to enable
the choice of PSK by using a cipher priority parameter such as in the
example below.
@smallexample
$ ./gnutls-cli -p 5556 localhost --pskusername psk_identity \
--pskkey 88f3824b3e5659f52d00e959bacab954b6540344 \
--priority NORMAL:-KX-ALL:+ECDHE-PSK:+DHE-PSK:+PSK
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
- PSK authentication.
- Version: TLS1.1
- Key Exchange: PSK
- Cipher: AES-128-CBC
- MAC: SHA1
- Compression: NULL
- Handshake was completed
- Simple Client Mode:
@end smallexample
By keeping the @code{--pskusername} parameter and removing the
@code{--pskkey} parameter, it will query only for the password during
the handshake.
@node Invoking gnutls-cli-debug
@section Invoking gnutls-cli-debug
@cindex gnutls-cli-debug
This program was created to assist in debugging @acronym{GnuTLS}, but
it might be useful to extract a @acronym{TLS} server's capabilities.
It's purpose is to connect onto a @acronym{TLS} server, perform some
tests and print the server's capabilities. If called with the `-v'
parameter more checks will be performed. An example output is:
@example
crystal:/cvs/gnutls/src$ ./gnutls-cli-debug localhost -p 5556
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
Checking for TLS 1.1 support... yes
Checking fallback from TLS 1.1 to... N/A
Checking for TLS 1.0 support... yes
Checking for SSL 3.0 support... yes
Checking for version rollback bug in RSA PMS... no
Checking for version rollback bug in Client Hello... no
Checking whether we need to disable TLS 1.0... N/A
Checking whether the server ignores the RSA PMS version... no
Checking whether the server can accept Hello Extensions... yes
Checking whether the server can accept cipher suites not in SSL 3.0 spec... yes
Checking for certificate information... N/A
Checking for trusted CAs... N/A
Checking whether the server understands TLS closure alerts... yes
Checking whether the server supports session resumption... yes
Checking for export-grade ciphersuite support... no
Checking RSA-export ciphersuite info... N/A
Checking for anonymous authentication support... no
Checking anonymous Diffie-Hellman group info... N/A
Checking for ephemeral Diffie-Hellman support... no
Checking ephemeral Diffie-Hellman group info... N/A
Checking for AES cipher support (TLS extension)... yes
Checking for 3DES cipher support... yes
Checking for ARCFOUR 128 cipher support... yes
Checking for ARCFOUR 40 cipher support... no
Checking for MD5 MAC support... yes
Checking for SHA1 MAC support... yes
Checking for ZLIB compression support (TLS extension)... yes
Checking for max record size (TLS extension)... yes
Checking for SRP authentication support (TLS extension)... yes
Checking for OpenPGP authentication support (TLS extension)... no
@end example
@node Invoking gnutls-serv
@section Invoking gnutls-serv
@cindex gnutls-serv
Simple server program that listens to incoming TLS connections.
@example
GnuTLS test server
Usage: gnutls-serv [options]
-d, --debug integer Enable debugging
-g, --generate Generate Diffie-Hellman Parameters.
-p, --port integer The port to connect to.
-q, --quiet Suppress some messages.
--nodb Does not use the resume database.
--http Act as an HTTP Server.
--echo Act as an Echo Server.
--dhparams FILE DH params file to use.
--x509fmtder Use DER format for certificates
--x509cafile FILE Certificate file to use.
--x509crlfile FILE CRL file to use.
--pgpkeyring FILE PGP Key ring file to use.
--pgpkeyfile FILE PGP Key file to use.
--pgpcertfile FILE PGP Public Key (certificate) file to
use.
--pgpsubkey HEX|auto PGP subkey to use.
--x509keyfile FILE X.509 key file to use.
--x509certfile FILE X.509 Certificate file to use.
--x509dsakeyfile FILE Alternative X.509 key file to use.
--x509dsacertfile FILE Alternative X.509 certificate file to
use.
-r, --require-cert Require a valid certificate.
-a, --disable-client-cert
Disable request for a client
certificate.
--pskpasswd FILE PSK password file to use.
--pskhint HINT PSK identity hint to use.
--srppasswd FILE SRP password file to use.
--srppasswdconf FILE SRP password conf file to use.
--opaque-prf-input DATA
Use Opaque PRF Input DATA.
--ciphers cipher1 cipher2...
Ciphers to enable.
--protocols protocol1 protocol2...
Protocols to enable.
--comp comp1 comp2... Compression methods to enable.
--macs mac1 mac2... MACs to enable.
--kx kx1 kx2... Key exchange methods to enable.
--ctypes certType1 certType2...
Certificate types to enable.
--priority PRIORITY STRING
Priorities string.
-l, --list Print a list of the supported
algorithms and modes.
-h, --help prints this help
-v, --version prints the program's version number
@end example
@subsection Setting up a test HTTPS server
@cindex HTTPS server
@cindex debug server
Running your own TLS server based on GnuTLS can be useful when
debugging clients and/or GnuTLS itself. This section describes how to
use @code{gnutls-serv} as a simple HTTPS server.
The most basic server can be started as:
@smallexample
gnutls-serv --http
@end smallexample
It will only support anonymous ciphersuites, which many TLS clients
refuse to use.
The next step is to add support for X.509. First we generate a CA:
@smallexample
$ certtool --generate-privkey > x509-ca-key.pem
$ echo 'cn = GnuTLS test CA' > ca.tmpl
$ echo 'ca' >> ca.tmpl
$ echo 'cert_signing_key' >> ca.tmpl
$ certtool --generate-self-signed --load-privkey x509-ca-key.pem \
--template ca.tmpl --outfile x509-ca.pem
...
@end smallexample
Then generate a server certificate. Remember to change the dns_name
value to the name of your server host, or skip that command to avoid
the field.
@example
$ certtool --generate-privkey > x509-server-key.pem
$ echo 'organization = GnuTLS test server' > server.tmpl
$ echo 'cn = test.gnutls.org' >> server.tmpl
$ echo 'tls_www_server' >> server.tmpl
$ echo 'encryption_key' >> server.tmpl
$ echo 'signing_key' >> server.tmpl
$ echo 'dns_name = test.gnutls.org' >> server.tmpl
$ certtool --generate-certificate --load-privkey x509-server-key.pem \
--load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
--template server.tmpl --outfile x509-server.pem
...
@end example
For use in the client, you may want to generate a client certificate
as well.
@example
$ certtool --generate-privkey > x509-client-key.pem
$ echo 'cn = GnuTLS test client' > client.tmpl
$ echo 'tls_www_client' >> client.tmpl
$ echo 'encryption_key' >> client.tmpl
$ echo 'signing_key' >> client.tmpl
$ certtool --generate-certificate --load-privkey x509-client-key.pem \
--load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
--template client.tmpl --outfile x509-client.pem
...
@end example
To be able to import the client key/certificate into some
applications, you will need to convert them into a PKCS#12 structure.
This also encrypts the security sensitive key with a password.
@smallexample
$ certtool --to-p12 --load-ca-certificate x509-ca.pem \
--load-privkey x509-client-key.pem --load-certificate x509-client.pem \
--outder --outfile x509-client.p12
@end smallexample
For icing, we'll create a proxy certificate for the client too.
@smallexample
$ certtool --generate-privkey > x509-proxy-key.pem
$ echo 'cn = GnuTLS test client proxy' > proxy.tmpl
$ certtool --generate-proxy --load-privkey x509-proxy-key.pem \
--load-ca-certificate x509-client.pem --load-ca-privkey x509-client-key.pem \
--load-certificate x509-client.pem --template proxy.tmpl \
--outfile x509-proxy.pem
...
@end smallexample
Then start the server again:
@smallexample
$ gnutls-serv --http \
--x509cafile x509-ca.pem \
--x509keyfile x509-server-key.pem \
--x509certfile x509-server.pem
@end smallexample
Try connecting to the server using your web browser. Note that the
server listens to port 5556 by default.
While you are at it, to allow connections using DSA, you can also
create a DSA key and certificate for the server. These credentials
will be used in the final example below.
@smallexample
$ certtool --generate-privkey --dsa > x509-server-key-dsa.pem
$ certtool --generate-certificate --load-privkey x509-server-key-dsa.pem \
--load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
--template server.tmpl --outfile x509-server-dsa.pem
...
@end smallexample
The next step is to create OpenPGP credentials for the server.
@smallexample
gpg --gen-key
...enter whatever details you want, use 'test.gnutls.org' as name...
@end smallexample
Make a note of the OpenPGP key identifier of the newly generated key,
here it was @code{5D1D14D8}. You will need to export the key for
GnuTLS to be able to use it.
@smallexample
gpg -a --export 5D1D14D8 > openpgp-server.txt
gpg --export 5D1D14D8 > openpgp-server.bin
gpg --export-secret-keys 5D1D14D8 > openpgp-server-key.bin
gpg -a --export-secret-keys 5D1D14D8 > openpgp-server-key.txt
@end smallexample
Let's start the server with support for OpenPGP credentials:
@smallexample
gnutls-serv --http \
--pgpkeyfile openpgp-server-key.txt \
--pgpcertfile openpgp-server.txt
@end smallexample
The next step is to add support for SRP authentication. This requires
an SRP password file (see @ref{Invoking srptool}).
To start the server with SRP support:
@smallexample
gnutls-serv --http \
--srppasswdconf srp-tpasswd.conf \
--srppasswd srp-passwd.txt
@end smallexample
Let's also start a server with support for PSK. This would require
a password file created with @code{psktool} (see @ref{Invoking psktool}).
@smallexample
gnutls-serv --http \
--pskpasswd psk-passwd.txt
@end smallexample
Finally, we start the server with all the earlier parameters and you
get this command:
@smallexample
gnutls-serv --http \
--x509cafile x509-ca.pem \
--x509keyfile x509-server-key.pem \
--x509certfile x509-server.pem \
--x509dsakeyfile x509-server-key-dsa.pem \
--x509dsacertfile x509-server-dsa.pem \
--pgpkeyfile openpgp-server-key.txt \
--pgpcertfile openpgp-server.txt \
--srppasswdconf srp-tpasswd.conf \
--srppasswd srp-passwd.txt \
--pskpasswd psk-passwd.txt
@end smallexample
@node Invoking psktool
@section Invoking psktool
@cindex psktool
This is a program to manage @acronym{PSK} username and keys.
It will generate random keys for the indicated username,
using a simple password file format.
@smallexample
PSKtool help
Usage : psktool [options]
-u, --username username
specify username.
-p, --passwd FILE specify a password file.
-s, --keysize SIZE specify the key size in bytes.
-v, --version prints the program's version number
-h, --help shows this help text
@end smallexample
The generation of a PSK password file is illustrated in the example below.
The password is provided in the prompt.
@smallexample
$ ./psktool -u psk_identity -p psks.txt
Enter password:
Key stored to psks.txt
$ cat psks.txt
psk_identity:88f3824b3e5659f52d00e959bacab954b6540344
$
@end smallexample
@node Invoking srptool
@section Invoking srptool
@anchor{srptool}
@cindex srptool
The @file{srptool} is a very simple program that emulates the programs
in the @emph{Stanford SRP libraries}@footnote{See
@url{http://srp.stanford.edu/}.}. It is intended for use in places
where you don't expect @acronym{SRP} authentication to be the used for
system users.
Traditionally @emph{libsrp} used two files. One called @code{tpasswd}
which holds usernames and verifiers, and @code{tpasswd.conf} which
holds generators and primes.
@subsection How to use srptool
To create tpasswd.conf which holds the g and n values for
@acronym{SRP} protocol (generator and a large prime), run:
@smallexample
$ srptool --create-conf /etc/tpasswd.conf
@end smallexample
This command will create /etc/tpasswd and will add user 'test' (you
will also be prompted for a password). Verifiers are stored by
default in the way libsrp expects.
@smallexample
$ srptool --passwd /etc/tpasswd \
--passwd-conf /etc/tpasswd.conf -u test
@end smallexample
This command will check against a password. If the password matches
the one in /etc/tpasswd you will get an ok.
@smallexample
$ srptool --passwd /etc/tpasswd \
--passwd-conf /etc/tpasswd.conf --verify -u test
@end smallexample
@node Invoking p11tool
@section Invoking p11tool
@anchor{p11tool}
@cindex p11tool
The @file{p11tool} is a program that helps with accessing tokens
and security modules that support the PKCS #11 API. It requires
the individual PKCS #11 modules to be loaded either with the
@code{--provider} option, or by setting up the GnuTLS configuration
file for PKCS #11 as in @ref{Hardware tokens}.
@example
p11tool help
Usage: p11tool [options]
Usage: p11tool --list-tokens
Usage: p11tool --list-all
Usage: p11tool --export 'pkcs11:...'
--export URL Export an object specified by a pkcs11
URL
--list-tokens List all available tokens
--list-mechanisms URL List all available mechanisms in token.
--list-all List all objects specified by a PKCS#11
URL
--list-all-certs List all certificates specified by a
PKCS#11 URL
--list-certs List certificates that have a private
key specified by a PKCS#11 URL
--list-privkeys List private keys specified by a
PKCS#11 URL
--list-trusted List certificates marked as trusted,
specified by a PKCS#11 URL
--initialize URL Initializes a PKCS11 token.
--write URL Writes loaded certificates, private or
secret keys to a PKCS11 token.
--delete URL Deletes objects matching the URL.
--label label Sets a label for the write operation.
--trusted Marks the certificate to be written as
trusted.
--private Marks the object to be written as
private (requires PIN).
--no-private Marks the object to be written as not
private.
--login Force login to token
--detailed-url Export detailed URLs.
--no-detailed-url Export less detailed URLs.
--secret-key HEX_KEY Provide a hex encoded secret key.
--load-privkey FILE Private key file to use.
--load-pubkey FILE Private key file to use.
--load-certificate FILE
Certificate file to use.
-8, --pkcs8 Use PKCS #8 format for private keys.
--inder Use DER format for input certificates
and private keys.
--inraw Use RAW/DER format for input
certificates and private keys.
--provider Library Specify the pkcs11 provider library
--outfile FILE Output file.
-d, --debug LEVEL specify the debug level. Default is 1.
-h, --help shows this help text
@end example
After being provided the available PKCS #11 modules, it can list all tokens
available in your system, the objects on the tokens, and perform operations
on them.
Some examples on how to use p11tool are illustrated in the following paragraphs.
@subsection List all tokens
@smallexample
$ p11tool --list-tokens
@end smallexample
@subsection List all objects
The following command will list all objects in a token. The @code{--login}
is required to show objects marked as private.
@smallexample
$ p11tool --login --list-all
@end smallexample
@subsection Exporting an object
To retrieve an object stored in the card use the following command.
Note however that objects marked as sensitive (typically PKCS #11 private keys)
are not allowed to be extracted from the token.
@smallexample
$ p11tool --login --export pkcs11:(OBJECT URL)
@end smallexample
@subsection Copy an object to a token
To copy an object, such as a certificate or private key to a token
use the following command.
@smallexample
$ p11tool --login --write pkcs11:(TOKEN URL) \
--load-certificate cert.pem --label "my_cert"
@end smallexample
|