1tpm2_create(1) General Commands Manual tpm2_create(1)
2
6 tpm2_create(1) - Create a child object.
7
9 tpm2_create [OPTIONS]
10
12 tpm2_create(1) - Create a child object. The object can either be a key
13 or a sealing object. A sealing object allows to seal user data to the
14 TPM, with a maximum size of 256 bytes. Additionally it will load the
15 created object if the -o is specified.
16
18 These options for creating the TPM entity:
19 · -C, --parent-context=OBJECT:
21 The parent of the object to be created.
23 · -P, --parent-auth=AUTH:
25 The authorization value of the parent object specified with -C.
27 · -p, --key-auth=AUTH:
29 The authorization value for the created object.
31 · -g, --hash-algorithm=ALGORITHM:
33 The hash algorithm for generating the objects name. This is optional
35 and defaults to sha256 when not specified.
36 · -G, --key-algorithm=ALGORITHM:
38 The key algorithm associated with this object. It defaults to "rsa"
40 if not specified.
41 · -a, --attributes=ATTRIBUTES:
43 The object attributes, optional. The default for created objects is:
45 TPMA_OBJECT_SIGN_ENCRYPT|TPMA_OBJECT_DECRYPT|TPMA_OB‐
47 JECT_FIXEDTPM| TPMA_OBJECT_FIXEDPARENT|TPMA_OBJECT_SENSITIVEDATAORI‐
48 GIN| TPMA_OBJECT_USERWITHAUTH
49 When -i is specified for sealing, TPMA_OBJECT_SIGN_ENCRYPT and TP‐
51 MA_OBJECT_DECRYPT are removed from the default attribute set. The
52 algorithm is set in a way where the the object is only good for seal‐
53 ing and unsealing. I.e. one cannot use an object for sealing and
54 cryptography operations.
55 · -i, --sealing-input=FILE or STDIN:
57 The data file to be sealed, optional. If file is -, read from stdin.
59 When sealing data only the TPM_ALG_KEYEDHASH algorithm with a NULL
60 scheme is allowed. Thus, -G cannot be specified.
61 · -L, --policy=FILE:
63 The input policy file, optional.
65 · -u, --public=FILE:
67 The output file which contains the public portion of the created ob‐
69 ject, optional.
70 · -r, --private=FILE:
72 The output file which contains the sensitive portion of the object,
74 optional.
75 · -c, --key-context=FILE:
77 The output file which contains the key context, optional. The key
79 context is analogous to the context file produced by tpm2_load(1),
80 however is generated via a tpm2_createloaded(1) command. This option
81 can be used to avoid the normal tpm2_create(1) and tpm2_load(1) com‐
82 mand sequences and do it all in one command, atomically.
83 References
86 The type of a context object, whether it is a handle or file name, is
87 determined according to the following logic in-order:
88 · If the argument is a file path, then the file is loaded as a restored
90 TPM transient object.
91 · If the argument is a prefix match on one of:
93 · owner: the owner hierarchy
95 · platform: the platform hierarchy
97 · endorsement: the endorsement hierarchy
99 · lockout: the lockout control persistent object
101 · If the argument argument can be loaded as a number it will be treat
103 as a handle, e.g. 0x81010013 and used directly.OBJECT.
104
106 Authorization for use of an object in TPM2.0 can come in 3 different
107 forms: 1. Password 2. HMAC 3. Sessions
108 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
110 fied".
111 Passwords
113 Passwords are interpreted in the following forms below using prefix
114 identifiers.
115 Note: By default passwords are assumed to be in the string form when
117 they do not have a prefix.
118 String
120 A string password, specified by prefix "str:" or it's absence (raw
121 string without prefix) is not interpreted, and is directly used for au‐
122 thorization.
123 Examples
125 foobar
126 str:foobar
127 Hex-string
129 A hex-string password, specified by prefix "hex:" is converted from a
130 hexidecimal form into a byte array form, thus allowing passwords with
131 non-printable and/or terminal un-friendly characters.
132 Example
134 hex:0x1122334455667788
135 File
137 A file based password, specified be prefix "file:" should be the path
138 of a file containing the password to be read by the tool or a "-" to
139 use stdin. Storing passwords in files prevents information leakage,
140 passwords passed as options can be read from the process list or common
141 shell history features.
142 Examples
144 # to use stdin and be prompted
145 file:-
146 # to use a file from a path
148 file:path/to/password/file
149 # to echo a password via stdin:
151 echo foobar | tpm2_tool -p file:-
152 # to use a bash here-string via stdin:
154 tpm2_tool -p file:- <<< foobar
156 Sessions
158 When using a policy session to authorize the use of an object, prefix
159 the option argument with the session keyword. Then indicate a path to
160 a session file that was created with tpm2_startauthsession(1). Option‐
161 ally, if the session requires an auth value to be sent with the session
162 handle (eg policy password), then append a + and a string as described
163 in the Passwords section.
164 Examples
166 To use a session context file called session.ctx.
167 session:session.ctx
169 To use a session context file called session.ctx AND send the authvalue
171 mypassword.
172 session:session.ctx+mypassword
174 To use a session context file called session.ctx AND send the HEX auth‐
176 value 0x11223344.
177 session:session.ctx+hex:11223344
179 PCR Authorizations
181 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
182 language. The PCR minilanguage is as follows:
183 <pcr-spec>=<raw-pcr-file>
184 The PCR spec is documented in in the section "PCR bank specifiers".
186 The raw-pcr-file is an optional the output of the raw PCR contents as
188 returned by tpm2_pcrread(1).
189 PCR bank specifiers (common/pcr.md)
191 Examples
193 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
194 er of:
195 pcr:sha256:0,1,2,3
197 specifying AUTH.
199
201 Options that take algorithms support "nice-names".
202 There are two major algorithm specification string classes, simple and
204 complex. Only certain algorithms will be accepted by the TPM, based on
205 usage and conditions.
206 Simple specifiers
208 These are strings with no additional specification data. When creating
209 objects, non-specified portions of an object are assumed to defaults.
210 You can find the list of known "Simple Specifiers Below".
211 Asymmetric
213 · rsa
214 · ecc
216 Symmetric
218 · aes
219 · camellia
221 Hashing Algorithms
223 · sha1
224 · sha256
226 · sha384
228 · sha512
230 · sm3_256
232 · sha3_256
234 · sha3_384
236 · sha3_512
238 Keyed Hash
240 · hmac
241 · xor
243 Signing Schemes
245 · rsassa
246 · rsapss
248 · ecdsa
250 · ecdaa
252 · ecschnorr
254 Asymmetric Encryption Schemes
256 · oaep
257 · rsaes
259 · ecdh
261 Modes
263 · ctr
264 · ofb
266 · cbc
268 · cfb
270 · ecb
272 Misc
274 · null
275 Complex Specifiers
277 Objects, when specified for creation by the TPM, have numerous algo‐
278 rithms to populate in the public data. Things like type, scheme and
279 asymmetric details, key size, etc. Below is the general format for
280 specifying this data: <type>:<scheme>:<symmetric-details>
281 Type Specifiers
283 This portion of the complex algorithm specifier is required. The re‐
284 maining scheme and symmetric details will default based on the type
285 specified and the type of the object being created.
286 · aes - Default AES: aes128
288 · aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
290 If mode is not specified, defaults to null.
291 · aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
293 · aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
295 · ecc - Elliptical Curve, defaults to ecc256.
297 · ecc192 - 192 bit ECC
299 · ecc224 - 224 bit ECC
301 · ecc256 - 256 bit ECC
303 · ecc384 - 384 bit ECC
305 · ecc521 - 521 bit ECC
307 · rsa - Default RSA: rsa2048
309 · rsa1024 - RSA with 1024 bit keysize.
311 · rsa2048 - RSA with 2048 bit keysize.
313 · rsa4096 - RSA with 4096 bit keysize.
315 Scheme Specifiers
317 Next, is an optional field, it can be skipped.
318 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
320 Most signing schemes take a hash algorithm directly following the sign‐
321 ing scheme. If the hash algorithm is missing, it defaults to sha256.
322 Some take no arguments, and some take multiple arguments.
323 Hash Optional Scheme Specifiers
325 These scheme specifiers are followed by a dash and a valid hash algo‐
326 rithm, For example: oaep-sha256.
327 · oaep
329 · ecdh
331 · rsassa
333 · rsapss
335 · ecdsa
337 · ecschnorr
339 Multiple Option Scheme Specifiers
341 This scheme specifier is followed by a count (max size UINT16) then
342 folloed by a dash(-) and a valid hash algorithm. * ecdaa For example,
343 ecdaa4-sha256. If no count is specified, it defaults to 4.
344 No Option Scheme Specifiers
346 This scheme specifier takes NO arguments. * rsaes
347 Symmetric Details Specifiers
349 This field is optional, and defaults based on the type of object being
350 created and it's attributes. Generally, any valid Symmetric specifier
351 from the Type Specifiers list should work. If not specified, an asym‐
352 metric objects symmetric details defaults to aes128cfb.
353 Examples
355 Create an rsa2048 key with an rsaes asymmetric encryption scheme
356 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
357 Create an ecc256 key with an ecdaa signing scheme with a count of 4
359 and sha384 hash
360 /tpm2_create -C parent.ctx -G ecc256:ec‐
362 daa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
363
365 Object Attributes are used to control various properties of created ob‐
366 jects. When specified as an option, either the raw bitfield mask or
367 "nice-names" may be used. The values can be found in Table 31 Part 2
368 of the TPM2.0 specification, which can be found here:
369 <https://trustedcomputinggroup.org/wp-content/uploads/TPM-
371 Rev-2.0-Part-2-Structures-01.38.pdf>
372 Nice names are calculated by taking the name field of table 31 and re‐
374 moving the prefix TPMA_OBJECT_ and lowercasing the result. Thus, TP‐
375 MA_OBJECT_FIXEDTPM becomes fixedtpm. Nice names can be joined using
376 the bitwise or "|" symbol.
377 For instance, to set The fields TPMA_OBJECT_FIXEDTPM, TPMA_OBJECT_NODA,
379 and TPMA_OBJECT_SIGN_ENCRYPT, the argument would be:
380 fixedtpm|noda|sign specifying the object attributes ATTRIBUTES.
382
384 This collection of options are common to many programs and provide in‐
385 formation that many users may expect.
386 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
388 attempts to invoke the manpager for the tool, however, on failure
389 will output a short tool summary. This is the same behavior if the
390 "man" option argument is specified, however if explicit "man" is re‐
391 quested, the tool will provide errors from man on stderr. If the
392 "no-man" option if specified, or the manpager fails, the short op‐
393 tions will be output to stdout.
394 To successfully use the manpages feature requires the manpages to be
396 installed or on MANPATH, See man(1) for more details.
397 · -v, --version: Display version information for this tool, supported
399 tctis and exit.
400 · -V, --verbose: Increase the information that the tool prints to the
402 console during its execution. When using this option the file and
403 line number are printed.
404 · -Q, --quiet: Silence normal tool output to stdout.
406 · -Z, --enable-errata: Enable the application of errata fixups. Useful
408 if an errata fixup needs to be applied to commands sent to the TPM.
409 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
410 formation many users may expect.
411
413 The TCTI or "Transmission Interface" is the communication mechanism
414 with the TPM. TCTIs can be changed for communication with TPMs across
415 different mediums.
416 To control the TCTI, the tools respect:
418 1. The command line option -T or --tcti
420 2. The environment variable: TPM2TOOLS_TCTI.
422 Note: The command line option always overrides the environment vari‐
424 able.
425 The current known TCTIs are:
427 · tabrmd - The resource manager, called tabrmd
429 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
430 abrmd as a tcti name are synonymous.
431 · mssim - Typically used for communicating to the TPM software simula‐
433 tor.
434 · device - Used when talking directly to a TPM device file.
436 · none - Do not initalize a connection with the TPM. Some tools allow
438 for off-tpm options and thus support not using a TCTI. Tools that do
439 not support it will error when attempted to be used without a TCTI
440 connection. Does not support ANY options and MUST BE presented as
441 the exact text of "none".
442 The arguments to either the command line option or the environment
444 variable are in the form:
445 <tcti-name>:<tcti-option-config>
447 Specifying an empty string for either the <tcti-name> or <tcti-op‐
449 tion-config> results in the default being used for that portion respec‐
450 tively.
451 TCTI Defaults
453 When a TCTI is not specified, the default TCTI is searched for using
454 dlopen(3) semantics. The tools will search for tabrmd, device and
455 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
456 what TCTI will be chosen as the default by using the -v option to print
457 the version information. The "default-tcti" key-value pair will indi‐
458 cate which of the aforementioned TCTIs is the default.
459 Custom TCTIs
461 Any TCTI that implements the dynamic TCTI interface can be loaded. The
462 tools internally use dlopen(3), and the raw tcti-name value is used for
463 the lookup. Thus, this could be a path to the shared library, or a li‐
464 brary name as understood by dlopen(3) semantics.
465
467 This collection of options are used to configure the various known TCTI
468 modules available:
469 · device: For the device TCTI, the TPM character device file for use by
471 the device TCTI can be specified. The default is /dev/tpm0.
472 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
474 vice:/dev/tpm0"
475 · mssim: For the mssim TCTI, the domain name or IP address and port
477 number used by the simulator can be specified. The default are
478 127.0.0.1 and 2321.
479 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
481 TI="mssim:host=localhost,port=2321"
482 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
484 ries of simple key value pairs separated by a ',' character. Each
485 key and value string are separated by a '=' character.
486 · TCTI abrmd supports two keys:
488 1. 'bus_name' : The name of the tabrmd service on the bus (a
490 string).
491 2. 'bus_type' : The type of the dbus instance (a string) limited to
493 'session' and 'system'.
494 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
496 ample.FooBar:
497 \--tcti=tabrmd:bus_name=com.example.FooBar
499 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
501 sion:
502 \--tcti:bus_type=session
504 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
506 ules.
507
509 Setup
510 In order to create an object, we must first create a primary key as
511 it's parent.
512 tpm2_createprimary -c primary.ctx
514 Create an Object
516 This will create an object using all the default values and store the
517 TPM sealed private and public portions to the paths specified via -u
518 and -r respectively. The tool defaults to an RSA key.
519 tpm2_create -C primary.ctx -u obj.pub -r obj.priv
521 Seal Data to the TPM
523 Outside of key objects, the TPM allows for small amounts of user speci‐
524 fied data to be sealed to the TPM.
525 echo "my sealed data" > seal.dat
527 tpm2_create -C primary.ctx -i seal.dat -u obj.pub -r obj.priv
528 Create an EC Key Object and Load it to the TPM
530 Normally, when creating an object, only the public and private portions
531 of the object are returned and the caller needs to use tpm2_load(1) to
532 load those public and private portions to the TPM before being able to
533 use the object. However, this can be accomplished within this command
534 as well.
535 tpm2_create -C primary.ctx -G ecc -u obj.pub -r obj.priv -c ecc.ctx
537
539 Tools can return any of the following codes:
540 · 0 - Success.
542 · 1 - General non-specific error.
544 · 2 - Options handling error.
546 · 3 - Authentication error.
548 · 4 - TCTI related error.
550 · 5 - Non supported scheme. Applicable to tpm2_testparams.
552
554 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
555
557 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
558tpm2-tools tpm2_create(1)