1tpm2_sign(1) General Commands Manual tpm2_sign(1)
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6 tpm2_sign(1) - Sign a hash or message using the TPM.
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9 tpm2_sign [OPTIONS] [ARGUMENT]
10
12 tpm2_sign(1) - Generates signature of specified message or message-di‐
13 gest using the specified symmetric or asymmetric signing key.
14 When signing a message, tpm2_sign utility first calculates the digest
16 of the message similar to the tpm2_hash command. It also generates a
17 validation ticket under TPM2_RH_NULL or TPM2_RH_OWNER hierarchies re‐
18 spectively for unrestricted or the restricted signing keys.
19 While signing messages is a provision in this tool it is recommended to
21 use the tpm2_hash tool first and pass the digest and validation ticket.
22 NOTE: If the signing key is a restricted signing key, then validation
24 and digest must be provided via the -t input. The ticket indicates
25 that the TPM performed the hash of the message.
26
28 • -c, --key-context=OBJECT:
29 Context object pointing to the the key used for signing. Either a
31 file or a handle number. See section “Context Object Format”.
32 • -p, --auth_AUTH_:
34 Optional authorization value to use the key specified by -c. Autho‐
36 rization values should follow the “authorization formatting stan‐
37 dards”, see section “Authorization Formatting”.
38 • -g, --hash-algorithm=ALGORITHM:
40 The hash algorithm used to digest the message. Algorithms should
42 follow the “formatting standards”, see section “Algorithm Speci‐
43 fiers”. Also, see section “Supported Hash Algorithms” for a list of
44 supported hash algorithms.
45 • -s, --scheme=ALGORITHM:
47 The signing scheme used to sign the message. Optional.
49 Signing schemes should follow the “formatting standards”, see section
51 “Algorithm Specifiers”.
52 If specified, the signature scheme must match the key type. If left
54 unspecified, a default signature scheme for the key type will be
55 used.
56 • -d, --digest:
58 Indicate that FILE is a file containing the digest of the message.
60 When this option and -t is specified, a warning is generated and the
61 validation ticket (-t) is ignored. You cannot use this option to
62 sign a digest against a restricted signing key.
63 • -t, --ticket=FILE:
65 The ticket file, containing the validation structure, optional.
67 • -o, --signature=FILE:
69 The signature file, records the signature structure.
71 • -f, --format=FORMAT:
73 Format selection for the signature output file. See section “Signa‐
75 ture Format Specifiers”.
76 • --cphash=FILE
78 File path to record the hash of the command parameters. This is com‐
80 monly termed as cpHash. NOTE: When this option is selected, The tool
81 will not actually execute the command, it simply returns a cpHash.
82 • --commit-index=NATURALNUMBER
84 The commit counter value to determine the key index to use in an EC‐
86 DAA signing scheme. The default counter value is 0.
87 • ARGUMENT the command line argument specifies the file data for sign.
89 References
92 The type of a context object, whether it is a handle or file name, is
93 determined according to the following logic in-order:
94 • If the argument is a file path, then the file is loaded as a restored
96 TPM transient object.
97 • If the argument is a prefix match on one of:
99 • owner: the owner hierarchy
101 • platform: the platform hierarchy
103 • endorsement: the endorsement hierarchy
105 • lockout: the lockout control persistent object
107 • If the argument argument can be loaded as a number it will be treat
109 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
110
112 Authorization for use of an object in TPM2.0 can come in 3 different
113 forms: 1. Password 2. HMAC 3. Sessions
114 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
116 fied”.
117 Passwords
119 Passwords are interpreted in the following forms below using prefix
120 identifiers.
121 Note: By default passwords are assumed to be in the string form when
123 they do not have a prefix.
124 String
126 A string password, specified by prefix “str:” or it’s absence (raw
127 string without prefix) is not interpreted, and is directly used for au‐
128 thorization.
129 Examples
131 foobar
132 str:foobar
133 Hex-string
135 A hex-string password, specified by prefix “hex:” is converted from a
136 hexidecimal form into a byte array form, thus allowing passwords with
137 non-printable and/or terminal un-friendly characters.
138 Example
140 hex:0x1122334455667788
141 File
143 A file based password, specified be prefix “file:” should be the path
144 of a file containing the password to be read by the tool or a “-” to
145 use stdin. Storing passwords in files prevents information leakage,
146 passwords passed as options can be read from the process list or common
147 shell history features.
148 Examples
150 # to use stdin and be prompted
151 file:-
152 # to use a file from a path
154 file:path/to/password/file
155 # to echo a password via stdin:
157 echo foobar | tpm2_tool -p file:-
158 # to use a bash here-string via stdin:
160 tpm2_tool -p file:- <<< foobar
162 Sessions
164 When using a policy session to authorize the use of an object, prefix
165 the option argument with the session keyword. Then indicate a path to
166 a session file that was created with tpm2_startauthsession(1). Option‐
167 ally, if the session requires an auth value to be sent with the session
168 handle (eg policy password), then append a + and a string as described
169 in the Passwords section.
170 Examples
172 To use a session context file called session.ctx.
173 session:session.ctx
175 To use a session context file called session.ctx AND send the authvalue
177 mypassword.
178 session:session.ctx+mypassword
180 To use a session context file called session.ctx AND send the HEX auth‐
182 value 0x11223344.
183 session:session.ctx+hex:11223344
185 PCR Authorizations
187 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
188 language. The PCR minilanguage is as follows:
189 <pcr-spec>=<raw-pcr-file>
190 The PCR spec is documented in in the section “PCR bank specifiers”.
192 The raw-pcr-file is an optional argument that contains the output of
194 the raw PCR contents as returned by tpm2_pcrread(1).
195 PCR bank specifiers (pcr.md)
197 Examples
199 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
200 er of:
201 pcr:sha256:0,1,2,3
203 specifying AUTH.
205
207 Options that take algorithms support “nice-names”.
208 There are two major algorithm specification string classes, simple and
210 complex. Only certain algorithms will be accepted by the TPM, based on
211 usage and conditions.
212 Simple specifiers
214 These are strings with no additional specification data. When creating
215 objects, non-specified portions of an object are assumed to defaults.
216 You can find the list of known “Simple Specifiers Below”.
217 Asymmetric
219 • rsa
220 • ecc
222 Symmetric
224 • aes
225 • camellia
227 Hashing Algorithms
229 • sha1
230 • sha256
232 • sha384
234 • sha512
236 • sm3_256
238 • sha3_256
240 • sha3_384
242 • sha3_512
244 Keyed Hash
246 • hmac
247 • xor
249 Signing Schemes
251 • rsassa
252 • rsapss
254 • ecdsa
256 • ecdaa
258 • ecschnorr
260 Asymmetric Encryption Schemes
262 • oaep
263 • rsaes
265 • ecdh
267 Modes
269 • ctr
270 • ofb
272 • cbc
274 • cfb
276 • ecb
278 Misc
280 • null
281 Complex Specifiers
283 Objects, when specified for creation by the TPM, have numerous algo‐
284 rithms to populate in the public data. Things like type, scheme and
285 asymmetric details, key size, etc. Below is the general format for
286 specifying this data: <type>:<scheme>:<symmetric-details>
287 Type Specifiers
289 This portion of the complex algorithm specifier is required. The re‐
290 maining scheme and symmetric details will default based on the type
291 specified and the type of the object being created.
292 • aes - Default AES: aes128
294 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
296 If mode is not specified, defaults to null.
297 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
299 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
301 • ecc - Elliptical Curve, defaults to ecc256.
303 • ecc192 - 192 bit ECC
305 • ecc224 - 224 bit ECC
307 • ecc256 - 256 bit ECC
309 • ecc384 - 384 bit ECC
311 • ecc521 - 521 bit ECC
313 • rsa - Default RSA: rsa2048
315 • rsa1024 - RSA with 1024 bit keysize.
317 • rsa2048 - RSA with 2048 bit keysize.
319 • rsa4096 - RSA with 4096 bit keysize.
321 Scheme Specifiers
323 Next, is an optional field, it can be skipped.
324 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
326 Most signing schemes take a hash algorithm directly following the sign‐
327 ing scheme. If the hash algorithm is missing, it defaults to sha256.
328 Some take no arguments, and some take multiple arguments.
329 Hash Optional Scheme Specifiers
331 These scheme specifiers are followed by a dash and a valid hash algo‐
332 rithm, For example: oaep-sha256.
333 • oaep
335 • ecdh
337 • rsassa
339 • rsapss
341 • ecdsa
343 • ecschnorr
345 Multiple Option Scheme Specifiers
347 This scheme specifier is followed by a count (max size UINT16) then
348 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
349 ecdaa4-sha256. If no count is specified, it defaults to 4.
350 No Option Scheme Specifiers
352 This scheme specifier takes NO arguments. * rsaes
353 Symmetric Details Specifiers
355 This field is optional, and defaults based on the type of object being
356 created and it’s attributes. Generally, any valid Symmetric specifier
357 from the Type Specifiers list should work. If not specified, an asym‐
358 metric objects symmetric details defaults to aes128cfb.
359 Examples
361 Create an rsa2048 key with an rsaes asymmetric encryption scheme
362 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
363 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
365 sha384 hash
366 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
367 key.priv cryptographic algorithms ALGORITHM.
368
370 This collection of options are common to many programs and provide in‐
371 formation that many users may expect.
372 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
374 attempts to invoke the manpager for the tool, however, on failure
375 will output a short tool summary. This is the same behavior if the
376 “man” option argument is specified, however if explicit “man” is re‐
377 quested, the tool will provide errors from man on stderr. If the
378 “no-man” option if specified, or the manpager fails, the short op‐
379 tions will be output to stdout.
380 To successfully use the manpages feature requires the manpages to be
382 installed or on MANPATH, See man(1) for more details.
383 • -v, --version: Display version information for this tool, supported
385 tctis and exit.
386 • -V, --verbose: Increase the information that the tool prints to the
388 console during its execution. When using this option the file and
389 line number are printed.
390 • -Q, --quiet: Silence normal tool output to stdout.
392 • -Z, --enable-errata: Enable the application of errata fixups. Useful
394 if an errata fixup needs to be applied to commands sent to the TPM.
395 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
396 formation many users may expect.
397
399 The TCTI or “Transmission Interface” is the communication mechanism
400 with the TPM. TCTIs can be changed for communication with TPMs across
401 different mediums.
402 To control the TCTI, the tools respect:
404 1. The command line option -T or --tcti
406 2. The environment variable: TPM2TOOLS_TCTI.
408 Note: The command line option always overrides the environment vari‐
410 able.
411 The current known TCTIs are:
413 • tabrmd - The resource manager, called tabrmd
415 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
416 abrmd as a tcti name are synonymous.
417 • mssim - Typically used for communicating to the TPM software simula‐
419 tor.
420 • device - Used when talking directly to a TPM device file.
422 • none - Do not initalize a connection with the TPM. Some tools allow
424 for off-tpm options and thus support not using a TCTI. Tools that do
425 not support it will error when attempted to be used without a TCTI
426 connection. Does not support ANY options and MUST BE presented as
427 the exact text of “none”.
428 The arguments to either the command line option or the environment
430 variable are in the form:
431 <tcti-name>:<tcti-option-config>
433 Specifying an empty string for either the <tcti-name> or <tcti-op‐
435 tion-config> results in the default being used for that portion respec‐
436 tively.
437 TCTI Defaults
439 When a TCTI is not specified, the default TCTI is searched for using
440 dlopen(3) semantics. The tools will search for tabrmd, device and
441 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
442 what TCTI will be chosen as the default by using the -v option to print
443 the version information. The “default-tcti” key-value pair will indi‐
444 cate which of the aforementioned TCTIs is the default.
445 Custom TCTIs
447 Any TCTI that implements the dynamic TCTI interface can be loaded. The
448 tools internally use dlopen(3), and the raw tcti-name value is used for
449 the lookup. Thus, this could be a path to the shared library, or a li‐
450 brary name as understood by dlopen(3) semantics.
451
453 This collection of options are used to configure the various known TCTI
454 modules available:
455 • device: For the device TCTI, the TPM character device file for use by
457 the device TCTI can be specified. The default is /dev/tpm0.
458 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
460 vice:/dev/tpm0”
461 • mssim: For the mssim TCTI, the domain name or IP address and port
463 number used by the simulator can be specified. The default are
464 127.0.0.1 and 2321.
465 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
467 TI=“mssim:host=localhost,port=2321”
468 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
470 ries of simple key value pairs separated by a `,' character. Each
471 key and value string are separated by a `=' character.
472 • TCTI abrmd supports two keys:
474 1. `bus_name' : The name of the tabrmd service on the bus (a
476 string).
477 2. `bus_type' : The type of the dbus instance (a string) limited to
479 `session' and `system'.
480 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
482 ample.FooBar:
483 \--tcti=tabrmd:bus_name=com.example.FooBar
485 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
487 sion:
488 \--tcti:bus_type=session
490 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
492 ules.
493
495 Format selection for the signature output file. tss (the default) will
496 output a binary blob according to the TPM 2.0 specification and any po‐
497 tential compiler padding. The option plain will output the plain sig‐
498 nature data as defined by the used cryptographic algorithm.
499
501 Sign and verify with the TPM using the endorsement hierarchy
502 tpm2_createprimary -C e -c primary.ctx
503 tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx
505 tpm2_load -C primary.ctx -u rsa.pub -r rsa.priv -c rsa.ctx
507 echo "my message" > message.dat
509 tpm2_sign -c rsa.ctx -g sha256 -o sig.rssa message.dat
511 tpm2_verifysignature -c rsa.ctx -g sha256 -s sig.rssa -m message.dat
513 Sign with the TPM and verify with OSSL
515 openssl ecparam -name prime256v1 -genkey -noout -out private.ecc.pem
516 openssl ec -in private.ecc.pem -out public.ecc.pem -pubout
518 # Generate a hash to sign
520 echo "data to sign" > data.in.raw
521 sha256sum data.in.raw | awk '{ print "000000 " $1 }' | \
523 xxd -r -c 32 > data.in.digest
524 # Load the private key for signing
526 tpm2_loadexternal -Q -G ecc -r private.ecc.pem -c key.ctx
527 # Sign in the TPM and verify with OSSL
529 tpm2_sign -Q -c key.ctx -g sha256 -d -f plain -o data.out.signed data.in.digest
530 openssl dgst -verify public.ecc.pem -keyform pem -sha256 \
532 -signature data.out.signed data.in.raw
533
535 Tools can return any of the following codes:
536 • 0 - Success.
538 • 1 - General non-specific error.
540 • 2 - Options handling error.
542 • 3 - Authentication error.
544 • 4 - TCTI related error.
546 • 5 - Non supported scheme. Applicable to tpm2_testparams.
548
550 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
551
553 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
554tpm2-tools tpm2_sign(1)