1tpm2_rsadecrypt(1) General Commands Manual tpm2_rsadecrypt(1)
2
6 tpm2_rsadecrypt(1) - Performs an RSA decryption operation using the
7 TPM.
8
10 tpm2_rsadecrypt [OPTIONS] [ARGUMENT]
11
13 tpm2_rsadecrypt(1) - Performs RSA decryption on the contents of file
14 using the indicated padding scheme according to IETF RFC 3447 (PKCS#1).
15 Command line argument defaults to stdin if not specified.
16 The key referenced by key-context is required to be:
18 1. An RSA key
20 2. Have the attribute decrypt SET in it's attributes.
22
24 · -c, --key-context=OBJECT:
25 Context object pointing to the the public portion of RSA key to use
27 for decryption. Either a file or a handle number. See section "Con‐
28 text Object Format".
29 · -p, --auth=AUTH:
31 Optional authorization value to use the key specified by -c.
33 · -o, --output=FILE:
35 Optional output file path to record the decrypted data to. The de‐
37 fault is to print the binary encrypted data to STDOUT.
38 · -s, --scheme=FORMAT:
40 Optional, set the padding scheme (defaults to rsaes).
42 · null - TPM_ALG_NULL uses the key's scheme if set.
44 · rsaes - TPM_ALG_RSAES which is RSAES_PKCSV1.5.
46 · oaep - TPM_ALG_OAEP which is RSAES_OAEP.
48 · -l, --label=FILE OR STRING:
50 Optional, set the label data.The TPM requires the last byte of the
52 label to be zero, this is handled internally to the tool. No other
53 embedded 0 bytes can exist or the TPM will truncate your label.
54 · ARGUMENT the command line argument specifies the file containing data
56 to be decrypted.
57 References
60 The type of a context object, whether it is a handle or file name, is
61 determined according to the following logic in-order:
62 · If the argument is a file path, then the file is loaded as a restored
64 TPM transient object.
65 · If the argument is a prefix match on one of:
67 · owner: the owner hierarchy
69 · platform: the platform hierarchy
71 · endorsement: the endorsement hierarchy
73 · lockout: the lockout control persistent object
75 · If the argument argument can be loaded as a number it will be treat
77 as a handle, e.g. 0x81010013 and used directly.OBJECT.
78
80 Authorization for use of an object in TPM2.0 can come in 3 different
81 forms: 1. Password 2. HMAC 3. Sessions
82 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
84 fied".
85 Passwords
87 Passwords are interpreted in the following forms below using prefix
88 identifiers.
89 Note: By default passwords are assumed to be in the string form when
91 they do not have a prefix.
92 String
94 A string password, specified by prefix "str:" or it's absence (raw
95 string without prefix) is not interpreted, and is directly used for au‐
96 thorization.
97 Examples
99 foobar
100 str:foobar
101 Hex-string
103 A hex-string password, specified by prefix "hex:" is converted from a
104 hexidecimal form into a byte array form, thus allowing passwords with
105 non-printable and/or terminal un-friendly characters.
106 Example
108 hex:0x1122334455667788
109 File
111 A file based password, specified be prefix "file:" should be the path
112 of a file containing the password to be read by the tool or a "-" to
113 use stdin. Storing passwords in files prevents information leakage,
114 passwords passed as options can be read from the process list or common
115 shell history features.
116 Examples
118 # to use stdin and be prompted
119 file:-
120 # to use a file from a path
122 file:path/to/password/file
123 # to echo a password via stdin:
125 echo foobar | tpm2_tool -p file:-
126 # to use a bash here-string via stdin:
128 tpm2_tool -p file:- <<< foobar
130 Sessions
132 When using a policy session to authorize the use of an object, prefix
133 the option argument with the session keyword. Then indicate a path to
134 a session file that was created with tpm2_startauthsession(1). Option‐
135 ally, if the session requires an auth value to be sent with the session
136 handle (eg policy password), then append a + and a string as described
137 in the Passwords section.
138 Examples
140 To use a session context file called session.ctx.
141 session:session.ctx
143 To use a session context file called session.ctx AND send the authvalue
145 mypassword.
146 session:session.ctx+mypassword
148 To use a session context file called session.ctx AND send the HEX auth‐
150 value 0x11223344.
151 session:session.ctx+hex:11223344
153 PCR Authorizations
155 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
156 language. The PCR minilanguage is as follows:
157 <pcr-spec>=<raw-pcr-file>
158 The PCR spec is documented in in the section "PCR bank specifiers".
160 The raw-pcr-file is an optional the output of the raw PCR contents as
162 returned by tpm2_pcrread(1).
163 PCR bank specifiers (common/pcr.md)
165 Examples
167 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
168 er of:
169 pcr:sha256:0,1,2,3
171 specifying AUTH.
173
175 This collection of options are common to many programs and provide in‐
176 formation that many users may expect.
177 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
179 attempts to invoke the manpager for the tool, however, on failure
180 will output a short tool summary. This is the same behavior if the
181 "man" option argument is specified, however if explicit "man" is re‐
182 quested, the tool will provide errors from man on stderr. If the
183 "no-man" option if specified, or the manpager fails, the short op‐
184 tions will be output to stdout.
185 To successfully use the manpages feature requires the manpages to be
187 installed or on MANPATH, See man(1) for more details.
188 · -v, --version: Display version information for this tool, supported
190 tctis and exit.
191 · -V, --verbose: Increase the information that the tool prints to the
193 console during its execution. When using this option the file and
194 line number are printed.
195 · -Q, --quiet: Silence normal tool output to stdout.
197 · -Z, --enable-errata: Enable the application of errata fixups. Useful
199 if an errata fixup needs to be applied to commands sent to the TPM.
200 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
201 formation many users may expect.
202
204 The TCTI or "Transmission Interface" is the communication mechanism
205 with the TPM. TCTIs can be changed for communication with TPMs across
206 different mediums.
207 To control the TCTI, the tools respect:
209 1. The command line option -T or --tcti
211 2. The environment variable: TPM2TOOLS_TCTI.
213 Note: The command line option always overrides the environment vari‐
215 able.
216 The current known TCTIs are:
218 · tabrmd - The resource manager, called tabrmd
220 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
221 abrmd as a tcti name are synonymous.
222 · mssim - Typically used for communicating to the TPM software simula‐
224 tor.
225 · device - Used when talking directly to a TPM device file.
227 · none - Do not initalize a connection with the TPM. Some tools allow
229 for off-tpm options and thus support not using a TCTI. Tools that do
230 not support it will error when attempted to be used without a TCTI
231 connection. Does not support ANY options and MUST BE presented as
232 the exact text of "none".
233 The arguments to either the command line option or the environment
235 variable are in the form:
236 <tcti-name>:<tcti-option-config>
238 Specifying an empty string for either the <tcti-name> or <tcti-op‐
240 tion-config> results in the default being used for that portion respec‐
241 tively.
242 TCTI Defaults
244 When a TCTI is not specified, the default TCTI is searched for using
245 dlopen(3) semantics. The tools will search for tabrmd, device and
246 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
247 what TCTI will be chosen as the default by using the -v option to print
248 the version information. The "default-tcti" key-value pair will indi‐
249 cate which of the aforementioned TCTIs is the default.
250 Custom TCTIs
252 Any TCTI that implements the dynamic TCTI interface can be loaded. The
253 tools internally use dlopen(3), and the raw tcti-name value is used for
254 the lookup. Thus, this could be a path to the shared library, or a li‐
255 brary name as understood by dlopen(3) semantics.
256
258 This collection of options are used to configure the various known TCTI
259 modules available:
260 · device: For the device TCTI, the TPM character device file for use by
262 the device TCTI can be specified. The default is /dev/tpm0.
263 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
265 vice:/dev/tpm0"
266 · mssim: For the mssim TCTI, the domain name or IP address and port
268 number used by the simulator can be specified. The default are
269 127.0.0.1 and 2321.
270 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
272 TI="mssim:host=localhost,port=2321"
273 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
275 ries of simple key value pairs separated by a ',' character. Each
276 key and value string are separated by a '=' character.
277 · TCTI abrmd supports two keys:
279 1. 'bus_name' : The name of the tabrmd service on the bus (a
281 string).
282 2. 'bus_type' : The type of the dbus instance (a string) limited to
284 'session' and 'system'.
285 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
287 ample.FooBar:
288 \--tcti=tabrmd:bus_name=com.example.FooBar
290 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
292 sion:
293 \--tcti:bus_type=session
295 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
297 ules.
298
300 Create an RSA key and load it
301 tpm2_createprimary -c primary.ctx
302 tpm2_create -C primary.ctx -Grsa2048 -u key.pub -r key.priv
303 tpm2_load -C primary.ctx -u key.pub -r key.priv -c key.ctx
304 Encrypt using RSA
306 echo "my message" > msg.dat
307 tpm2_rsaencrypt -c key.ctx -o msg.enc msg.dat
308 Decrypt using RSA
310 tpm2_rsadecrypt -c key.ctx -o msg.ptext msg.enc
311 cat msg.ptext
312 my message
313
315 Tools can return any of the following codes:
316 · 0 - Success.
318 · 1 - General non-specific error.
320 · 2 - Options handling error.
322 · 3 - Authentication error.
324 · 4 - TCTI related error.
326 · 5 - Non supported scheme. Applicable to tpm2_testparams.
328
330 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
331
333 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
334tpm2-tools tpm2_rsadecrypt(1)