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 · --cphash=FILE
58 File path to record the hash of the command parameters. This is com‐
60 monly termed as cpHash. NOTE: When this option is selected, The tool
61 will not actually execute the command, it simply returns a cpHash.
62 References
65 The type of a context object, whether it is a handle or file name, is
66 determined according to the following logic in-order:
67 · If the argument is a file path, then the file is loaded as a restored
69 TPM transient object.
70 · If the argument is a prefix match on one of:
72 · owner: the owner hierarchy
74 · platform: the platform hierarchy
76 · endorsement: the endorsement hierarchy
78 · lockout: the lockout control persistent object
80 · If the argument argument can be loaded as a number it will be treat
82 as a handle, e.g. 0x81010013 and used directly.OBJECT.
83
85 Authorization for use of an object in TPM2.0 can come in 3 different
86 forms: 1. Password 2. HMAC 3. Sessions
87 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
89 fied".
90 Passwords
92 Passwords are interpreted in the following forms below using prefix
93 identifiers.
94 Note: By default passwords are assumed to be in the string form when
96 they do not have a prefix.
97 String
99 A string password, specified by prefix "str:" or it's absence (raw
100 string without prefix) is not interpreted, and is directly used for au‐
101 thorization.
102 Examples
104 foobar
105 str:foobar
106 Hex-string
108 A hex-string password, specified by prefix "hex:" is converted from a
109 hexidecimal form into a byte array form, thus allowing passwords with
110 non-printable and/or terminal un-friendly characters.
111 Example
113 hex:0x1122334455667788
114 File
116 A file based password, specified be prefix "file:" should be the path
117 of a file containing the password to be read by the tool or a "-" to
118 use stdin. Storing passwords in files prevents information leakage,
119 passwords passed as options can be read from the process list or common
120 shell history features.
121 Examples
123 # to use stdin and be prompted
124 file:-
125 # to use a file from a path
127 file:path/to/password/file
128 # to echo a password via stdin:
130 echo foobar | tpm2_tool -p file:-
131 # to use a bash here-string via stdin:
133 tpm2_tool -p file:- <<< foobar
135 Sessions
137 When using a policy session to authorize the use of an object, prefix
138 the option argument with the session keyword. Then indicate a path to
139 a session file that was created with tpm2_startauthsession(1). Option‐
140 ally, if the session requires an auth value to be sent with the session
141 handle (eg policy password), then append a + and a string as described
142 in the Passwords section.
143 Examples
145 To use a session context file called session.ctx.
146 session:session.ctx
148 To use a session context file called session.ctx AND send the authvalue
150 mypassword.
151 session:session.ctx+mypassword
153 To use a session context file called session.ctx AND send the HEX auth‐
155 value 0x11223344.
156 session:session.ctx+hex:11223344
158 PCR Authorizations
160 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
161 language. The PCR minilanguage is as follows:
162 <pcr-spec>=<raw-pcr-file>
163 The PCR spec is documented in in the section "PCR bank specifiers".
165 The raw-pcr-file is an optional the output of the raw PCR contents as
167 returned by tpm2_pcrread(1).
168 PCR bank specifiers (common/pcr.md)
170 Examples
172 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
173 er of:
174 pcr:sha256:0,1,2,3
176 specifying AUTH.
178
180 Options that take algorithms support "nice-names".
181 There are two major algorithm specification string classes, simple and
183 complex. Only certain algorithms will be accepted by the TPM, based on
184 usage and conditions.
185 Simple specifiers
187 These are strings with no additional specification data. When creating
188 objects, non-specified portions of an object are assumed to defaults.
189 You can find the list of known "Simple Specifiers Below".
190 Asymmetric
192 · rsa
193 · ecc
195 Symmetric
197 · aes
198 · camellia
200 Hashing Algorithms
202 · sha1
203 · sha256
205 · sha384
207 · sha512
209 · sm3_256
211 · sha3_256
213 · sha3_384
215 · sha3_512
217 Keyed Hash
219 · hmac
220 · xor
222 Signing Schemes
224 · rsassa
225 · rsapss
227 · ecdsa
229 · ecdaa
231 · ecschnorr
233 Asymmetric Encryption Schemes
235 · oaep
236 · rsaes
238 · ecdh
240 Modes
242 · ctr
243 · ofb
245 · cbc
247 · cfb
249 · ecb
251 Misc
253 · null
254 Complex Specifiers
256 Objects, when specified for creation by the TPM, have numerous algo‐
257 rithms to populate in the public data. Things like type, scheme and
258 asymmetric details, key size, etc. Below is the general format for
259 specifying this data: <type>:<scheme>:<symmetric-details>
260 Type Specifiers
262 This portion of the complex algorithm specifier is required. The re‐
263 maining scheme and symmetric details will default based on the type
264 specified and the type of the object being created.
265 · aes - Default AES: aes128
267 · aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
269 If mode is not specified, defaults to null.
270 · aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
272 · aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
274 · ecc - Elliptical Curve, defaults to ecc256.
276 · ecc192 - 192 bit ECC
278 · ecc224 - 224 bit ECC
280 · ecc256 - 256 bit ECC
282 · ecc384 - 384 bit ECC
284 · ecc521 - 521 bit ECC
286 · rsa - Default RSA: rsa2048
288 · rsa1024 - RSA with 1024 bit keysize.
290 · rsa2048 - RSA with 2048 bit keysize.
292 · rsa4096 - RSA with 4096 bit keysize.
294 Scheme Specifiers
296 Next, is an optional field, it can be skipped.
297 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
299 Most signing schemes take a hash algorithm directly following the sign‐
300 ing scheme. If the hash algorithm is missing, it defaults to sha256.
301 Some take no arguments, and some take multiple arguments.
302 Hash Optional Scheme Specifiers
304 These scheme specifiers are followed by a dash and a valid hash algo‐
305 rithm, For example: oaep-sha256.
306 · oaep
308 · ecdh
310 · rsassa
312 · rsapss
314 · ecdsa
316 · ecschnorr
318 Multiple Option Scheme Specifiers
320 This scheme specifier is followed by a count (max size UINT16) then
321 folloed by a dash(-) and a valid hash algorithm. * ecdaa For example,
322 ecdaa4-sha256. If no count is specified, it defaults to 4.
323 No Option Scheme Specifiers
325 This scheme specifier takes NO arguments. * rsaes
326 Symmetric Details Specifiers
328 This field is optional, and defaults based on the type of object being
329 created and it's attributes. Generally, any valid Symmetric specifier
330 from the Type Specifiers list should work. If not specified, an asym‐
331 metric objects symmetric details defaults to aes128cfb.
332 Examples
334 Create an rsa2048 key with an rsaes asymmetric encryption scheme
335 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
336 Create an ecc256 key with an ecdaa signing scheme with a count of 4
338 and sha384 hash
339 /tpm2_create -C parent.ctx -G ecc256:ec‐
341 daa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
342
344 Format selection for the signature output file. tss (the default) will
345 output a binary blob according to the TPM 2.0 specification and any po‐
346 tential compiler padding. The option plain will output the plain sig‐
347 nature data as defined by the used cryptographic algorithm. signature
348 FORMAT.
349
351 This collection of options are common to many programs and provide in‐
352 formation that many users may expect.
353 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
355 attempts to invoke the manpager for the tool, however, on failure
356 will output a short tool summary. This is the same behavior if the
357 "man" option argument is specified, however if explicit "man" is re‐
358 quested, the tool will provide errors from man on stderr. If the
359 "no-man" option if specified, or the manpager fails, the short op‐
360 tions will be output to stdout.
361 To successfully use the manpages feature requires the manpages to be
363 installed or on MANPATH, See man(1) for more details.
364 · -v, --version: Display version information for this tool, supported
366 tctis and exit.
367 · -V, --verbose: Increase the information that the tool prints to the
369 console during its execution. When using this option the file and
370 line number are printed.
371 · -Q, --quiet: Silence normal tool output to stdout.
373 · -Z, --enable-errata: Enable the application of errata fixups. Useful
375 if an errata fixup needs to be applied to commands sent to the TPM.
376 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
377 formation many users may expect.
378
380 The TCTI or "Transmission Interface" is the communication mechanism
381 with the TPM. TCTIs can be changed for communication with TPMs across
382 different mediums.
383 To control the TCTI, the tools respect:
385 1. The command line option -T or --tcti
387 2. The environment variable: TPM2TOOLS_TCTI.
389 Note: The command line option always overrides the environment vari‐
391 able.
392 The current known TCTIs are:
394 · tabrmd - The resource manager, called tabrmd
396 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
397 abrmd as a tcti name are synonymous.
398 · mssim - Typically used for communicating to the TPM software simula‐
400 tor.
401 · device - Used when talking directly to a TPM device file.
403 · none - Do not initalize a connection with the TPM. Some tools allow
405 for off-tpm options and thus support not using a TCTI. Tools that do
406 not support it will error when attempted to be used without a TCTI
407 connection. Does not support ANY options and MUST BE presented as
408 the exact text of "none".
409 The arguments to either the command line option or the environment
411 variable are in the form:
412 <tcti-name>:<tcti-option-config>
414 Specifying an empty string for either the <tcti-name> or <tcti-op‐
416 tion-config> results in the default being used for that portion respec‐
417 tively.
418 TCTI Defaults
420 When a TCTI is not specified, the default TCTI is searched for using
421 dlopen(3) semantics. The tools will search for tabrmd, device and
422 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
423 what TCTI will be chosen as the default by using the -v option to print
424 the version information. The "default-tcti" key-value pair will indi‐
425 cate which of the aforementioned TCTIs is the default.
426 Custom TCTIs
428 Any TCTI that implements the dynamic TCTI interface can be loaded. The
429 tools internally use dlopen(3), and the raw tcti-name value is used for
430 the lookup. Thus, this could be a path to the shared library, or a li‐
431 brary name as understood by dlopen(3) semantics.
432
434 This collection of options are used to configure the various known TCTI
435 modules available:
436 · device: For the device TCTI, the TPM character device file for use by
438 the device TCTI can be specified. The default is /dev/tpm0.
439 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
441 vice:/dev/tpm0"
442 · mssim: For the mssim TCTI, the domain name or IP address and port
444 number used by the simulator can be specified. The default are
445 127.0.0.1 and 2321.
446 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
448 TI="mssim:host=localhost,port=2321"
449 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
451 ries of simple key value pairs separated by a ',' character. Each
452 key and value string are separated by a '=' character.
453 · TCTI abrmd supports two keys:
455 1. 'bus_name' : The name of the tabrmd service on the bus (a
457 string).
458 2. 'bus_type' : The type of the dbus instance (a string) limited to
460 'session' and 'system'.
461 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
463 ample.FooBar:
464 \--tcti=tabrmd:bus_name=com.example.FooBar
466 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
468 sion:
469 \--tcti:bus_type=session
471 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
473 ules.
474
476 Create a primary key and certify it with a signing key.
477 tpm2_createprimary -Q -C e -g sha256 -G rsa -c primary.ctx
479 tpm2_create -Q -g sha256 -G rsa -u certify.pub -r certify.priv -C primary.ctx
481 tpm2_load -Q -C primary.ctx -u certify.pub -r certify.priv -n certify.name \
483 -c certify.ctx
484 tpm2_certify -Q -c primary.ctx -C certify.ctx -g sha256 -o attest.out -s sig.out
486
488 Tools can return any of the following codes:
489 · 0 - Success.
491 · 1 - General non-specific error.
493 · 2 - Options handling error.
495 · 3 - Authentication error.
497 · 4 - TCTI related error.
499 · 5 - Non supported scheme. Applicable to tpm2_testparams.
501
503 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
504
506 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
507tpm2-tools tpm2_certify(1)