1tpm2_ecdhkeygen(1) General Commands Manual tpm2_ecdhkeygen(1)
2
6 tpm2_ecdhkeygen(1) - Creates an ephemeral key and uses it to generate
7 the shared secret value using the parameters from a ECC public key.
8
10 tpm2_ecdhkeygen [OPTIONS]
11
13 tpm2_ecdhkeygen(1) - Creates an ephemeral key and uses it to generate
14 the shared secret value using the parameters from a ECC public key.
15
17 • -c, --context=FILE:
18 Context object pointing to ECC public key. Either a file or a handle
20 number. See section "Context Object Format".
21 • -u, --public=FILE:
23 Output ECC point Q.
25 • -o, --output=FILE
27 Specify file path to save the calculated ecdh secret or Z point.
29 References
32 Options that take algorithms support "nice-names".
33 There are two major algorithm specification string classes, simple and
35 complex. Only certain algorithms will be accepted by the TPM, based on
36 usage and conditions.
37 Simple specifiers
39 These are strings with no additional specification data. When creating
40 objects, non-specified portions of an object are assumed to defaults.
41 You can find the list of known "Simple Specifiers Below".
42 Asymmetric
44 • rsa
45 • ecc
47 Symmetric
49 • aes
50 • camellia
52 Hashing Algorithms
54 • sha1
55 • sha256
57 • sha384
59 • sha512
61 • sm3_256
63 • sha3_256
65 • sha3_384
67 • sha3_512
69 Keyed Hash
71 • hmac
72 • xor
74 Signing Schemes
76 • rsassa
77 • rsapss
79 • ecdsa
81 • ecdaa
83 • ecschnorr
85 Asymmetric Encryption Schemes
87 • oaep
88 • rsaes
90 • ecdh
92 Modes
94 • ctr
95 • ofb
97 • cbc
99 • cfb
101 • ecb
103 Misc
105 • null
106 Complex Specifiers
108 Objects, when specified for creation by the TPM, have numerous algo‐
109 rithms to populate in the public data. Things like type, scheme and
110 asymmetric details, key size, etc. Below is the general format for
111 specifying this data: <type>:<scheme>:<symmetric-details>
112 Type Specifiers
114 This portion of the complex algorithm specifier is required. The re‐
115 maining scheme and symmetric details will default based on the type
116 specified and the type of the object being created.
117 • aes - Default AES: aes128
119 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
121 If mode is not specified, defaults to null.
122 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
124 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
126 • ecc - Elliptical Curve, defaults to ecc256.
128 • ecc192 - 192 bit ECC
130 • ecc224 - 224 bit ECC
132 • ecc256 - 256 bit ECC
134 • ecc384 - 384 bit ECC
136 • ecc521 - 521 bit ECC
138 • rsa - Default RSA: rsa2048
140 • rsa1024 - RSA with 1024 bit keysize.
142 • rsa2048 - RSA with 2048 bit keysize.
144 • rsa4096 - RSA with 4096 bit keysize.
146 Scheme Specifiers
148 Next, is an optional field, it can be skipped.
149 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
151 Most signing schemes take a hash algorithm directly following the sign‐
152 ing scheme. If the hash algorithm is missing, it defaults to sha256.
153 Some take no arguments, and some take multiple arguments.
154 Hash Optional Scheme Specifiers
156 These scheme specifiers are followed by a dash and a valid hash algo‐
157 rithm, For example: oaep-sha256.
158 • oaep
160 • ecdh
162 • rsassa
164 • rsapss
166 • ecdsa
168 • ecschnorr
170 Multiple Option Scheme Specifiers
172 This scheme specifier is followed by a count (max size UINT16) then
173 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
174 ecdaa4-sha256. If no count is specified, it defaults to 4.
175 No Option Scheme Specifiers
177 This scheme specifier takes NO arguments. * rsaes
178 Symmetric Details Specifiers
180 This field is optional, and defaults based on the type of object being
181 created and it's attributes. Generally, any valid Symmetric specifier
182 from the Type Specifiers list should work. If not specified, an asym‐
183 metric objects symmetric details defaults to aes128cfb.
184 Examples
186 Create an rsa2048 key with an rsaes asymmetric encryption scheme
187 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
188 Create an ecc256 key with an ecdaa signing scheme with a count of 4
190 and sha384 hash
191 /tpm2_create -C parent.ctx -G ecc256:ec‐
193 daa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
194
196 This collection of options are common to many programs and provide in‐
197 formation that many users may expect.
198 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
200 attempts to invoke the manpager for the tool, however, on failure
201 will output a short tool summary. This is the same behavior if the
202 "man" option argument is specified, however if explicit "man" is re‐
203 quested, the tool will provide errors from man on stderr. If the
204 "no-man" option if specified, or the manpager fails, the short op‐
205 tions will be output to stdout.
206 To successfully use the manpages feature requires the manpages to be
208 installed or on MANPATH, See man(1) for more details.
209 • -v, --version: Display version information for this tool, supported
211 tctis and exit.
212 • -V, --verbose: Increase the information that the tool prints to the
214 console during its execution. When using this option the file and
215 line number are printed.
216 • -Q, --quiet: Silence normal tool output to stdout.
218 • -Z, --enable-errata: Enable the application of errata fixups. Useful
220 if an errata fixup needs to be applied to commands sent to the TPM.
221 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
222 formation many users may expect.
223
225 The TCTI or "Transmission Interface" is the communication mechanism
226 with the TPM. TCTIs can be changed for communication with TPMs across
227 different mediums.
228 To control the TCTI, the tools respect:
230 1. The command line option -T or --tcti
232 2. The environment variable: TPM2TOOLS_TCTI.
234 Note: The command line option always overrides the environment vari‐
236 able.
237 The current known TCTIs are:
239 • tabrmd - The resource manager, called tabrmd
241 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
242 abrmd as a tcti name are synonymous.
243 • mssim - Typically used for communicating to the TPM software simula‐
245 tor.
246 • device - Used when talking directly to a TPM device file.
248 • none - Do not initalize a connection with the TPM. Some tools allow
250 for off-tpm options and thus support not using a TCTI. Tools that do
251 not support it will error when attempted to be used without a TCTI
252 connection. Does not support ANY options and MUST BE presented as
253 the exact text of "none".
254 The arguments to either the command line option or the environment
256 variable are in the form:
257 <tcti-name>:<tcti-option-config>
259 Specifying an empty string for either the <tcti-name> or <tcti-op‐
261 tion-config> results in the default being used for that portion respec‐
262 tively.
263 TCTI Defaults
265 When a TCTI is not specified, the default TCTI is searched for using
266 dlopen(3) semantics. The tools will search for tabrmd, device and
267 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
268 what TCTI will be chosen as the default by using the -v option to print
269 the version information. The "default-tcti" key-value pair will indi‐
270 cate which of the aforementioned TCTIs is the default.
271 Custom TCTIs
273 Any TCTI that implements the dynamic TCTI interface can be loaded. The
274 tools internally use dlopen(3), and the raw tcti-name value is used for
275 the lookup. Thus, this could be a path to the shared library, or a li‐
276 brary name as understood by dlopen(3) semantics.
277
279 This collection of options are used to configure the various known TCTI
280 modules available:
281 • device: For the device TCTI, the TPM character device file for use by
283 the device TCTI can be specified. The default is /dev/tpm0.
284 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
286 vice:/dev/tpm0"
287 • mssim: For the mssim TCTI, the domain name or IP address and port
289 number used by the simulator can be specified. The default are
290 127.0.0.1 and 2321.
291 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
293 TI="mssim:host=localhost,port=2321"
294 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
296 ries of simple key value pairs separated by a ',' character. Each
297 key and value string are separated by a '=' character.
298 • TCTI abrmd supports two keys:
300 1. 'bus_name' : The name of the tabrmd service on the bus (a
302 string).
303 2. 'bus_type' : The type of the dbus instance (a string) limited to
305 'session' and 'system'.
306 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
308 ample.FooBar:
309 \--tcti=tabrmd:bus_name=com.example.FooBar
311 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
313 sion:
314 \--tcti:bus_type=session
316 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
318 ules.
319
321 tpm2_createprimary -C o -c prim.ctx -Q
322 tpm2_create -C prim.ctx -c key.ctx -u key.pub -r key.priv -G ecc256:ecdaa
324 tpm2_ecdhkeygen -u ecdh.pub -o ecdh.priv -c key.ctx
326
328 Tools can return any of the following codes:
329 • 0 - Success.
331 • 1 - General non-specific error.
333 • 2 - Options handling error.
335 • 3 - Authentication error.
337 • 4 - TCTI related error.
339 • 5 - Non supported scheme. Applicable to tpm2_testparams.
341
343 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
344
346 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
347tpm2-tools tpm2_ecdhkeygen(1)