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]
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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 unless rphash is also required.
63 • --rphash=FILE
65 File path to record the hash of the response parameters. This is
67 commonly termed as rpHash.
68 • -S, --session=FILE:
70 The session created using tpm2_startauthsession. This can be used to
72 specify an auxiliary session for auditing and or encryption/decryp‐
73 tion of the parameters.
74 References
77 The type of a context object, whether it is a handle or file name, is
78 determined according to the following logic in-order:
79 • If the argument is a file path, then the file is loaded as a restored
81 TPM transient object.
82 • If the argument is a prefix match on one of:
84 • owner: the owner hierarchy
86 • platform: the platform hierarchy
88 • endorsement: the endorsement hierarchy
90 • lockout: the lockout control persistent object
92 • If the argument argument can be loaded as a number it will be treat
94 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
95
97 Authorization for use of an object in TPM2.0 can come in 3 different
98 forms: 1. Password 2. HMAC 3. Sessions
99 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
101 fied”.
102 Passwords
104 Passwords are interpreted in the following forms below using prefix
105 identifiers.
106 Note: By default passwords are assumed to be in the string form when
108 they do not have a prefix.
109 String
111 A string password, specified by prefix “str:” or it’s absence (raw
112 string without prefix) is not interpreted, and is directly used for au‐
113 thorization.
114 Examples
116 foobar
117 str:foobar
118 Hex-string
120 A hex-string password, specified by prefix “hex:” is converted from a
121 hexidecimal form into a byte array form, thus allowing passwords with
122 non-printable and/or terminal un-friendly characters.
123 Example
125 hex:0x1122334455667788
126 File
128 A file based password, specified be prefix “file:” should be the path
129 of a file containing the password to be read by the tool or a “-” to
130 use stdin. Storing passwords in files prevents information leakage,
131 passwords passed as options can be read from the process list or common
132 shell history features.
133 Examples
135 # to use stdin and be prompted
136 file:-
137 # to use a file from a path
139 file:path/to/password/file
140 # to echo a password via stdin:
142 echo foobar | tpm2_tool -p file:-
143 # to use a bash here-string via stdin:
145 tpm2_tool -p file:- <<< foobar
147 Sessions
149 When using a policy session to authorize the use of an object, prefix
150 the option argument with the session keyword. Then indicate a path to
151 a session file that was created with tpm2_startauthsession(1). Option‐
152 ally, if the session requires an auth value to be sent with the session
153 handle (eg policy password), then append a + and a string as described
154 in the Passwords section.
155 Examples
157 To use a session context file called session.ctx.
158 session:session.ctx
160 To use a session context file called session.ctx AND send the authvalue
162 mypassword.
163 session:session.ctx+mypassword
165 To use a session context file called session.ctx AND send the HEX auth‐
167 value 0x11223344.
168 session:session.ctx+hex:11223344
170 PCR Authorizations
172 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
173 language. The PCR minilanguage is as follows:
174 <pcr-spec>=<raw-pcr-file>
175 The PCR spec is documented in in the section “PCR bank specifiers”.
177 The raw-pcr-file is an optional argument that contains the output of
179 the raw PCR contents as returned by tpm2_pcrread(1).
180 PCR bank specifiers (pcr.md)
182 Examples
184 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
185 er of:
186 pcr:sha256:0,1,2,3
188 specifying AUTH.
190
192 Options that take algorithms support “nice-names”.
193 There are two major algorithm specification string classes, simple and
195 complex. Only certain algorithms will be accepted by the TPM, based on
196 usage and conditions.
197 Simple specifiers
199 These are strings with no additional specification data. When creating
200 objects, non-specified portions of an object are assumed to defaults.
201 You can find the list of known “Simple Specifiers Below”.
202 Asymmetric
204 • rsa
205 • ecc
207 Symmetric
209 • aes
210 • camellia
212 Hashing Algorithms
214 • sha1
215 • sha256
217 • sha384
219 • sha512
221 • sm3_256
223 • sha3_256
225 • sha3_384
227 • sha3_512
229 Keyed Hash
231 • hmac
232 • xor
234 Signing Schemes
236 • rsassa
237 • rsapss
239 • ecdsa
241 • ecdaa
243 • ecschnorr
245 Asymmetric Encryption Schemes
247 • oaep
248 • rsaes
250 • ecdh
252 Modes
254 • ctr
255 • ofb
257 • cbc
259 • cfb
261 • ecb
263 Misc
265 • null
266 Complex Specifiers
268 Objects, when specified for creation by the TPM, have numerous algo‐
269 rithms to populate in the public data. Things like type, scheme and
270 asymmetric details, key size, etc. Below is the general format for
271 specifying this data: <type>:<scheme>:<symmetric-details>
272 Type Specifiers
274 This portion of the complex algorithm specifier is required. The re‐
275 maining scheme and symmetric details will default based on the type
276 specified and the type of the object being created.
277 • aes - Default AES: aes128
279 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
281 If mode is not specified, defaults to null.
282 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
284 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
286 • ecc - Elliptical Curve, defaults to ecc256.
288 • ecc192 - 192 bit ECC
290 • ecc224 - 224 bit ECC
292 • ecc256 - 256 bit ECC
294 • ecc384 - 384 bit ECC
296 • ecc521 - 521 bit ECC
298 • rsa - Default RSA: rsa2048
300 • rsa1024 - RSA with 1024 bit keysize.
302 • rsa2048 - RSA with 2048 bit keysize.
304 • rsa4096 - RSA with 4096 bit keysize.
306 Scheme Specifiers
308 Next, is an optional field, it can be skipped.
309 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
311 Most signing schemes take a hash algorithm directly following the sign‐
312 ing scheme. If the hash algorithm is missing, it defaults to sha256.
313 Some take no arguments, and some take multiple arguments.
314 Hash Optional Scheme Specifiers
316 These scheme specifiers are followed by a dash and a valid hash algo‐
317 rithm, For example: oaep-sha256.
318 • oaep
320 • ecdh
322 • rsassa
324 • rsapss
326 • ecdsa
328 • ecschnorr
330 Multiple Option Scheme Specifiers
332 This scheme specifier is followed by a count (max size UINT16) then
333 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
334 ecdaa4-sha256. If no count is specified, it defaults to 4.
335 No Option Scheme Specifiers
337 This scheme specifier takes NO arguments. * rsaes
338 Symmetric Details Specifiers
340 This field is optional, and defaults based on the type of object being
341 created and it’s attributes. Generally, any valid Symmetric specifier
342 from the Type Specifiers list should work. If not specified, an asym‐
343 metric objects symmetric details defaults to aes128cfb.
344 Examples
346 Create an rsa2048 key with an rsaes asymmetric encryption scheme
347 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
348 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
350 sha384 hash
351 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
352 key.priv cryptographic algorithms ALGORITHM.
353
355 Format selection for the signature output file. tss (the default) will
356 output a binary blob according to the TPM 2.0 specification and any po‐
357 tential compiler padding. The option plain will output the plain sig‐
358 nature data as defined by the used cryptographic algorithm. signature
359 FORMAT.
360
362 This collection of options are common to many programs and provide in‐
363 formation that many users may expect.
364 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
366 attempts to invoke the manpager for the tool, however, on failure
367 will output a short tool summary. This is the same behavior if the
368 “man” option argument is specified, however if explicit “man” is re‐
369 quested, the tool will provide errors from man on stderr. If the
370 “no-man” option if specified, or the manpager fails, the short op‐
371 tions will be output to stdout.
372 To successfully use the manpages feature requires the manpages to be
374 installed or on MANPATH, See man(1) for more details.
375 • -v, --version: Display version information for this tool, supported
377 tctis and exit.
378 • -V, --verbose: Increase the information that the tool prints to the
380 console during its execution. When using this option the file and
381 line number are printed.
382 • -Q, --quiet: Silence normal tool output to stdout.
384 • -Z, --enable-errata: Enable the application of errata fixups. Useful
386 if an errata fixup needs to be applied to commands sent to the TPM.
387 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
388 formation many users may expect.
389
391 The TCTI or “Transmission Interface” is the communication mechanism
392 with the TPM. TCTIs can be changed for communication with TPMs across
393 different mediums.
394 To control the TCTI, the tools respect:
396 1. The command line option -T or --tcti
398 2. The environment variable: TPM2TOOLS_TCTI.
400 Note: The command line option always overrides the environment vari‐
402 able.
403 The current known TCTIs are:
405 • tabrmd - The resource manager, called tabrmd
407 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
408 abrmd as a tcti name are synonymous.
409 • mssim - Typically used for communicating to the TPM software simula‐
411 tor.
412 • device - Used when talking directly to a TPM device file.
414 • none - Do not initalize a connection with the TPM. Some tools allow
416 for off-tpm options and thus support not using a TCTI. Tools that do
417 not support it will error when attempted to be used without a TCTI
418 connection. Does not support ANY options and MUST BE presented as
419 the exact text of “none”.
420 The arguments to either the command line option or the environment
422 variable are in the form:
423 <tcti-name>:<tcti-option-config>
425 Specifying an empty string for either the <tcti-name> or <tcti-op‐
427 tion-config> results in the default being used for that portion respec‐
428 tively.
429 TCTI Defaults
431 When a TCTI is not specified, the default TCTI is searched for using
432 dlopen(3) semantics. The tools will search for tabrmd, device and
433 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
434 what TCTI will be chosen as the default by using the -v option to print
435 the version information. The “default-tcti” key-value pair will indi‐
436 cate which of the aforementioned TCTIs is the default.
437 Custom TCTIs
439 Any TCTI that implements the dynamic TCTI interface can be loaded. The
440 tools internally use dlopen(3), and the raw tcti-name value is used for
441 the lookup. Thus, this could be a path to the shared library, or a li‐
442 brary name as understood by dlopen(3) semantics.
443
445 This collection of options are used to configure the various known TCTI
446 modules available:
447 • device: For the device TCTI, the TPM character device file for use by
449 the device TCTI can be specified. The default is /dev/tpm0.
450 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
452 vice:/dev/tpm0”
453 • mssim: For the mssim TCTI, the domain name or IP address and port
455 number used by the simulator can be specified. The default are
456 127.0.0.1 and 2321.
457 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
459 TI=“mssim:host=localhost,port=2321”
460 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
462 ries of simple key value pairs separated by a `,' character. Each
463 key and value string are separated by a `=' character.
464 • TCTI abrmd supports two keys:
466 1. `bus_name' : The name of the tabrmd service on the bus (a
468 string).
469 2. `bus_type' : The type of the dbus instance (a string) limited to
471 `session' and `system'.
472 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
474 ample.FooBar:
475 \--tcti=tabrmd:bus_name=com.example.FooBar
477 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
479 sion:
480 \--tcti:bus_type=session
482 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
484 ules.
485
487 Create a primary key and certify it with a signing key.
488 tpm2_createprimary -Q -C e -g sha256 -G rsa -c primary.ctx
490 tpm2_create -Q -g sha256 -G rsa -u certify.pub -r certify.priv -C primary.ctx
492 tpm2_load -Q -C primary.ctx -u certify.pub -r certify.priv -n certify.name \
494 -c certify.ctx
495 tpm2_certify -Q -c primary.ctx -C certify.ctx -g sha256 -o attest.out -s sig.out
497
499 Tools can return any of the following codes:
500 • 0 - Success.
502 • 1 - General non-specific error.
504 • 2 - Options handling error.
506 • 3 - Authentication error.
508 • 4 - TCTI related error.
510 • 5 - Non supported scheme. Applicable to tpm2_testparams.
512
514 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
515
517 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
518tpm2-tools tpm2_certify(1)