1tpm2_certify(1) General Commands Manual tpm2_certify(1)
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6 tpm2_certify(1) - Prove that an object is loaded in the TPM.
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9 tpm2_certify [OPTIONS]
10
12 tpm2_certify(1) - Proves that an object with a specific NAME is loaded
13 in the TPM. By certifying that the object is loaded, the TPM warrants
14 that a public area with a given NAME is self-consistent and associated
15 with a valid sensitive area.
16 If a relying party has a public area that has the same NAME as a NAME
18 certified with this command, then the values in that public area are
19 correct. An object that only has its public area loaded cannot be cer‐
20 tified.
21
23 These options control the certification:
24 · -c, --certifiedkey-context=OBJECT:
26 The object to be certified.
28 · -C, --signingkey-context=OBJECT:
30 The key used to sign the attestation structure.
32 · -p, --certifiedkey-auth=AUTH:
34 The authorization value provided for the object specified with -c.
36 · -g, --hash-algorithm=ALGORITHM:
38 The hash algorithm to use in signature generation.
40 · -P, --signingkey-auth=AUTH:
42 The authorization value for the signing key specified with -C.
44 · -o, --attestation=FILE:
46 Output file name for the attestation data.
48 · -s, --signature=FILE:
50 Output file name for the signature data.
52 · -f, --format=FORMAT:
54 Format selection for the signature output file.
56 References
59 The type of a context object, whether it is a handle or file name, is
60 determined according to the following logic in-order:
61 · If the argument is a file path, then the file is loaded as a restored
63 TPM transient object.
64 · If the argument is a prefix match on one of:
66 · owner: the owner hierarchy
68 · platform: the platform hierarchy
70 · endorsement: the endorsement hierarchy
72 · lockout: the lockout control persistent object
74 · If the argument argument can be loaded as a number it will be treat
76 as a handle, e.g. 0x81010013 and used directly.OBJECT.
77
79 Authorization for use of an object in TPM2.0 can come in 3 different
80 forms: 1. Password 2. HMAC 3. Sessions
81 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
83 fied".
84 Passwords
86 Passwords are interpreted in the following forms below using prefix
87 identifiers.
88 Note: By default passwords are assumed to be in the string form when
90 they do not have a prefix.
91 String
93 A string password, specified by prefix "str:" or it's absence (raw
94 string without prefix) is not interpreted, and is directly used for au‐
95 thorization.
96 Examples
98 foobar
99 str:foobar
100 Hex-string
102 A hex-string password, specified by prefix "hex:" is converted from a
103 hexidecimal form into a byte array form, thus allowing passwords with
104 non-printable and/or terminal un-friendly characters.
105 Example
107 hex:0x1122334455667788
108 File
110 A file based password, specified be prefix "file:" should be the path
111 of a file containing the password to be read by the tool or a "-" to
112 use stdin. Storing passwords in files prevents information leakage,
113 passwords passed as options can be read from the process list or common
114 shell history features.
115 Examples
117 # to use stdin and be prompted
118 file:-
119 # to use a file from a path
121 file:path/to/password/file
122 # to echo a password via stdin:
124 echo foobar | tpm2_tool -p file:-
125 # to use a bash here-string via stdin:
127 tpm2_tool -p file:- <<< foobar
129 Sessions
131 When using a policy session to authorize the use of an object, prefix
132 the option argument with the session keyword. Then indicate a path to
133 a session file that was created with tpm2_startauthsession(1). Option‐
134 ally, if the session requires an auth value to be sent with the session
135 handle (eg policy password), then append a + and a string as described
136 in the Passwords section.
137 Examples
139 To use a session context file called session.ctx.
140 session:session.ctx
142 To use a session context file called session.ctx AND send the authvalue
144 mypassword.
145 session:session.ctx+mypassword
147 To use a session context file called session.ctx AND send the HEX auth‐
149 value 0x11223344.
150 session:session.ctx+hex:11223344
152 PCR Authorizations
154 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
155 language. The PCR minilanguage is as follows:
156 <pcr-spec>=<raw-pcr-file>
157 The PCR spec is documented in in the section "PCR bank specifiers".
159 The raw-pcr-file is an optional the output of the raw PCR contents as
161 returned by tpm2_pcrread(1).
162 PCR bank specifiers (common/pcr.md)
164 Examples
166 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
167 er of:
168 pcr:sha256:0,1,2,3
170 specifying AUTH.
172
174 Options that take algorithms support "nice-names".
175 There are two major algorithm specification string classes, simple and
177 complex. Only certain algorithms will be accepted by the TPM, based on
178 usage and conditions.
179 Simple specifiers
181 These are strings with no additional specification data. When creating
182 objects, non-specified portions of an object are assumed to defaults.
183 You can find the list of known "Simple Specifiers Below".
184 Asymmetric
186 · rsa
187 · ecc
189 Symmetric
191 · aes
192 · camellia
194 Hashing Algorithms
196 · sha1
197 · sha256
199 · sha384
201 · sha512
203 · sm3_256
205 · sha3_256
207 · sha3_384
209 · sha3_512
211 Keyed Hash
213 · hmac
214 · xor
216 Signing Schemes
218 · rsassa
219 · rsapss
221 · ecdsa
223 · ecdaa
225 · ecschnorr
227 Asymmetric Encryption Schemes
229 · oaep
230 · rsaes
232 · ecdh
234 Modes
236 · ctr
237 · ofb
239 · cbc
241 · cfb
243 · ecb
245 Misc
247 · null
248 Complex Specifiers
250 Objects, when specified for creation by the TPM, have numerous algo‐
251 rithms to populate in the public data. Things like type, scheme and
252 asymmetric details, key size, etc. Below is the general format for
253 specifying this data: <type>:<scheme>:<symmetric-details>
254 Type Specifiers
256 This portion of the complex algorithm specifier is required. The re‐
257 maining scheme and symmetric details will default based on the type
258 specified and the type of the object being created.
259 · aes - Default AES: aes128
261 · aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
263 If mode is not specified, defaults to null.
264 · aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
266 · aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
268 · ecc - Elliptical Curve, defaults to ecc256.
270 · ecc192 - 192 bit ECC
272 · ecc224 - 224 bit ECC
274 · ecc256 - 256 bit ECC
276 · ecc384 - 384 bit ECC
278 · ecc521 - 521 bit ECC
280 · rsa - Default RSA: rsa2048
282 · rsa1024 - RSA with 1024 bit keysize.
284 · rsa2048 - RSA with 2048 bit keysize.
286 · rsa4096 - RSA with 4096 bit keysize.
288 Scheme Specifiers
290 Next, is an optional field, it can be skipped.
291 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
293 Most signing schemes take a hash algorithm directly following the sign‐
294 ing scheme. If the hash algorithm is missing, it defaults to sha256.
295 Some take no arguments, and some take multiple arguments.
296 Hash Optional Scheme Specifiers
298 These scheme specifiers are followed by a dash and a valid hash algo‐
299 rithm, For example: oaep-sha256.
300 · oaep
302 · ecdh
304 · rsassa
306 · rsapss
308 · ecdsa
310 · ecschnorr
312 Multiple Option Scheme Specifiers
314 This scheme specifier is followed by a count (max size UINT16) then
315 folloed by a dash(-) and a valid hash algorithm. * ecdaa For example,
316 ecdaa4-sha256. If no count is specified, it defaults to 4.
317 No Option Scheme Specifiers
319 This scheme specifier takes NO arguments. * rsaes
320 Symmetric Details Specifiers
322 This field is optional, and defaults based on the type of object being
323 created and it's attributes. Generally, any valid Symmetric specifier
324 from the Type Specifiers list should work. If not specified, an asym‐
325 metric objects symmetric details defaults to aes128cfb.
326 Examples
328 Create an rsa2048 key with an rsaes asymmetric encryption scheme
329 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
330 Create an ecc256 key with an ecdaa signing scheme with a count of 4
332 and sha384 hash
333 /tpm2_create -C parent.ctx -G ecc256:ec‐
335 daa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
336
338 Format selection for the signature output file. tss (the default) will
339 output a binary blob according to the TPM 2.0 specification and any po‐
340 tential compiler padding. The option plain will output the plain sig‐
341 nature data as defined by the used cryptographic algorithm. signature
342 FORMAT.
343
345 This collection of options are common to many programs and provide in‐
346 formation that many users may expect.
347 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
349 attempts to invoke the manpager for the tool, however, on failure
350 will output a short tool summary. This is the same behavior if the
351 "man" option argument is specified, however if explicit "man" is re‐
352 quested, the tool will provide errors from man on stderr. If the
353 "no-man" option if specified, or the manpager fails, the short op‐
354 tions will be output to stdout.
355 To successfully use the manpages feature requires the manpages to be
357 installed or on MANPATH, See man(1) for more details.
358 · -v, --version: Display version information for this tool, supported
360 tctis and exit.
361 · -V, --verbose: Increase the information that the tool prints to the
363 console during its execution. When using this option the file and
364 line number are printed.
365 · -Q, --quiet: Silence normal tool output to stdout.
367 · -Z, --enable-errata: Enable the application of errata fixups. Useful
369 if an errata fixup needs to be applied to commands sent to the TPM.
370 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
371 formation many users may expect.
372
374 The TCTI or "Transmission Interface" is the communication mechanism
375 with the TPM. TCTIs can be changed for communication with TPMs across
376 different mediums.
377 To control the TCTI, the tools respect:
379 1. The command line option -T or --tcti
381 2. The environment variable: TPM2TOOLS_TCTI.
383 Note: The command line option always overrides the environment vari‐
385 able.
386 The current known TCTIs are:
388 · tabrmd - The resource manager, called tabrmd
390 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
391 abrmd as a tcti name are synonymous.
392 · mssim - Typically used for communicating to the TPM software simula‐
394 tor.
395 · device - Used when talking directly to a TPM device file.
397 · none - Do not initalize a connection with the TPM. Some tools allow
399 for off-tpm options and thus support not using a TCTI. Tools that do
400 not support it will error when attempted to be used without a TCTI
401 connection. Does not support ANY options and MUST BE presented as
402 the exact text of "none".
403 The arguments to either the command line option or the environment
405 variable are in the form:
406 <tcti-name>:<tcti-option-config>
408 Specifying an empty string for either the <tcti-name> or <tcti-op‐
410 tion-config> results in the default being used for that portion respec‐
411 tively.
412 TCTI Defaults
414 When a TCTI is not specified, the default TCTI is searched for using
415 dlopen(3) semantics. The tools will search for tabrmd, device and
416 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
417 what TCTI will be chosen as the default by using the -v option to print
418 the version information. The "default-tcti" key-value pair will indi‐
419 cate which of the aforementioned TCTIs is the default.
420 Custom TCTIs
422 Any TCTI that implements the dynamic TCTI interface can be loaded. The
423 tools internally use dlopen(3), and the raw tcti-name value is used for
424 the lookup. Thus, this could be a path to the shared library, or a li‐
425 brary name as understood by dlopen(3) semantics.
426
428 This collection of options are used to configure the various known TCTI
429 modules available:
430 · device: For the device TCTI, the TPM character device file for use by
432 the device TCTI can be specified. The default is /dev/tpm0.
433 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
435 vice:/dev/tpm0"
436 · mssim: For the mssim TCTI, the domain name or IP address and port
438 number used by the simulator can be specified. The default are
439 127.0.0.1 and 2321.
440 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
442 TI="mssim:host=localhost,port=2321"
443 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
445 ries of simple key value pairs separated by a ',' character. Each
446 key and value string are separated by a '=' character.
447 · TCTI abrmd supports two keys:
449 1. 'bus_name' : The name of the tabrmd service on the bus (a
451 string).
452 2. 'bus_type' : The type of the dbus instance (a string) limited to
454 'session' and 'system'.
455 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
457 ample.FooBar:
458 \--tcti=tabrmd:bus_name=com.example.FooBar
460 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
462 sion:
463 \--tcti:bus_type=session
465 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
467 ules.
468
470 tpm2_certify -H 0x81010002 -P 0x0011 -p 0x00FF -g 0x00B -a <fileName> \
471 -s <fileName>
472 tpm2_certify -C obj.context -c key.context -P 0x0011 -p 0x00FF -g 0x00B \
474 -a <fileName> -s <fileName>
475 tpm2_certify -H 0x81010002 -P 0011 -p 00FF -g 0x00B -a <fileName> -s <fileName>
477
479 Tools can return any of the following codes:
480 · 0 - Success.
482 · 1 - General non-specific error.
484 · 2 - Options handling error.
486 · 3 - Authentication error.
488 · 4 - TCTI related error.
490 · 5 - Non supported scheme. Applicable to tpm2_testparams.
492
494 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
495
497 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
498tpm2-tools tpm2_certify(1)