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 and
190 sha384 hash
191 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
192 key.priv cryptographic algorithms ALGORITHM.
193
195 This collection of options are common to many programs and provide in‐
196 formation that many users may expect.
197 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
199 attempts to invoke the manpager for the tool, however, on failure
200 will output a short tool summary. This is the same behavior if the
201 “man” option argument is specified, however if explicit “man” is re‐
202 quested, the tool will provide errors from man on stderr. If the
203 “no-man” option if specified, or the manpager fails, the short op‐
204 tions will be output to stdout.
205 To successfully use the manpages feature requires the manpages to be
207 installed or on MANPATH, See man(1) for more details.
208 • -v, --version: Display version information for this tool, supported
210 tctis and exit.
211 • -V, --verbose: Increase the information that the tool prints to the
213 console during its execution. When using this option the file and
214 line number are printed.
215 • -Q, --quiet: Silence normal tool output to stdout.
217 • -Z, --enable-errata: Enable the application of errata fixups. Useful
219 if an errata fixup needs to be applied to commands sent to the TPM.
220 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
221 formation many users may expect.
222
224 The TCTI or “Transmission Interface” is the communication mechanism
225 with the TPM. TCTIs can be changed for communication with TPMs across
226 different mediums.
227 To control the TCTI, the tools respect:
229 1. The command line option -T or --tcti
231 2. The environment variable: TPM2TOOLS_TCTI.
233 Note: The command line option always overrides the environment vari‐
235 able.
236 The current known TCTIs are:
238 • tabrmd - The resource manager, called tabrmd
240 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
241 abrmd as a tcti name are synonymous.
242 • mssim - Typically used for communicating to the TPM software simula‐
244 tor.
245 • device - Used when talking directly to a TPM device file.
247 • none - Do not initalize a connection with the TPM. Some tools allow
249 for off-tpm options and thus support not using a TCTI. Tools that do
250 not support it will error when attempted to be used without a TCTI
251 connection. Does not support ANY options and MUST BE presented as
252 the exact text of “none”.
253 The arguments to either the command line option or the environment
255 variable are in the form:
256 <tcti-name>:<tcti-option-config>
258 Specifying an empty string for either the <tcti-name> or <tcti-op‐
260 tion-config> results in the default being used for that portion respec‐
261 tively.
262 TCTI Defaults
264 When a TCTI is not specified, the default TCTI is searched for using
265 dlopen(3) semantics. The tools will search for tabrmd, device and
266 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
267 what TCTI will be chosen as the default by using the -v option to print
268 the version information. The “default-tcti” key-value pair will indi‐
269 cate which of the aforementioned TCTIs is the default.
270 Custom TCTIs
272 Any TCTI that implements the dynamic TCTI interface can be loaded. The
273 tools internally use dlopen(3), and the raw tcti-name value is used for
274 the lookup. Thus, this could be a path to the shared library, or a li‐
275 brary name as understood by dlopen(3) semantics.
276
278 This collection of options are used to configure the various known TCTI
279 modules available:
280 • device: For the device TCTI, the TPM character device file for use by
282 the device TCTI can be specified. The default is /dev/tpm0.
283 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
285 vice:/dev/tpm0”
286 • mssim: For the mssim TCTI, the domain name or IP address and port
288 number used by the simulator can be specified. The default are
289 127.0.0.1 and 2321.
290 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
292 TI=“mssim:host=localhost,port=2321”
293 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
295 ries of simple key value pairs separated by a `,' character. Each
296 key and value string are separated by a `=' character.
297 • TCTI abrmd supports two keys:
299 1. `bus_name' : The name of the tabrmd service on the bus (a
301 string).
302 2. `bus_type' : The type of the dbus instance (a string) limited to
304 `session' and `system'.
305 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
307 ample.FooBar:
308 \--tcti=tabrmd:bus_name=com.example.FooBar
310 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
312 sion:
313 \--tcti:bus_type=session
315 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
317 ules.
318
320 tpm2_createprimary -C o -c prim.ctx -Q
321 tpm2_create -C prim.ctx -c key.ctx -u key.pub -r key.priv -G ecc256:ecdaa
323 tpm2_ecdhkeygen -u ecdh.pub -o ecdh.priv -c key.ctx
325
327 Tools can return any of the following codes:
328 • 0 - Success.
330 • 1 - General non-specific error.
332 • 2 - Options handling error.
334 • 3 - Authentication error.
336 • 4 - TCTI related error.
338 • 5 - Non supported scheme. Applicable to tpm2_testparams.
340
342 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
343
345 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
346tpm2-tools tpm2_ecdhkeygen(1)