1 ========================== 1 ==========================
2 Trusted and Encrypted Keys 2 Trusted and Encrypted Keys
3 ========================== 3 ==========================
4 4
5 Trusted and Encrypted Keys are two new key typ 5 Trusted and Encrypted Keys are two new key types added to the existing kernel
6 key ring service. Both of these new types are 6 key ring service. Both of these new types are variable length symmetric keys,
7 and in both cases all keys are created in the 7 and in both cases all keys are created in the kernel, and user space sees,
8 stores, and loads only encrypted blobs. Trust 8 stores, and loads only encrypted blobs. Trusted Keys require the availability
9 of a Trust Source for greater security, while !! 9 of a Trusted Platform Module (TPM) chip for greater security, while Encrypted
10 system. All user level blobs, are displayed an !! 10 Keys can be used on any system. All user level blobs, are displayed and loaded
11 convenience, and are integrity verified. !! 11 in hex ascii for convenience, and are integrity verified.
>> 12
>> 13 Trusted Keys use a TPM both to generate and to seal the keys. Keys are sealed
>> 14 under a 2048 bit RSA key in the TPM, and optionally sealed to specified PCR
>> 15 (integrity measurement) values, and only unsealed by the TPM, if PCRs and blob
>> 16 integrity verifications match. A loaded Trusted Key can be updated with new
>> 17 (future) PCR values, so keys are easily migrated to new pcr values, such as
>> 18 when the kernel and initramfs are updated. The same key can have many saved
>> 19 blobs under different PCR values, so multiple boots are easily supported.
>> 20
>> 21 TPM 1.2
>> 22 -------
>> 23
>> 24 By default, trusted keys are sealed under the SRK, which has the default
>> 25 authorization value (20 zeros). This can be set at takeownership time with the
>> 26 trouser's utility: "tpm_takeownership -u -z".
12 27
>> 28 TPM 2.0
>> 29 -------
13 30
14 Trust Source !! 31 The user must first create a storage key and make it persistent, so the key is
15 ============ !! 32 available after reboot. This can be done using the following commands.
16 <<
17 A trust source provides the source of security <<
18 section lists currently supported trust source <<
19 considerations. Whether or not a trust source <<
20 on the strength and correctness of its impleme <<
21 environment for a specific use case. Since th <<
22 environment is, and there is no metric of trus <<
23 consumer of the Trusted Keys to determine if t <<
24 safe. <<
25 <<
26 * Root of trust for storage <<
27 <<
28 (1) TPM (Trusted Platform Module: hardwar <<
29 <<
30 Rooted to Storage Root Key (SRK) whic <<
31 provides crypto operation to establis <<
32 <<
33 (2) TEE (Trusted Execution Environment: O <<
34 <<
35 Rooted to Hardware Unique Key (HUK) w <<
36 fuses and is accessible to TEE only. <<
37 <<
38 (3) CAAM (Cryptographic Acceleration and <<
39 <<
40 When High Assurance Boot (HAB) is ena <<
41 mode, trust is rooted to the OTPMK, a <<
42 randomly generated and fused into eac <<
43 Otherwise, a common fixed test key is <<
44 <<
45 (4) DCP (Data Co-Processor: crypto accele <<
46 <<
47 Rooted to a one-time programmable key <<
48 in the on-chip fuses and is accessibl <<
49 DCP provides two keys that can be use <<
50 and the UNIQUE key. Default is to use <<
51 the OTP key can be done via a module <<
52 <<
53 * Execution isolation <<
54 <<
55 (1) TPM <<
56 <<
57 Fixed set of operations running in is <<
58 <<
59 (2) TEE <<
60 <<
61 Customizable set of operations runnin <<
62 environment verified via Secure/Trust <<
63 <<
64 (3) CAAM <<
65 <<
66 Fixed set of operations running in is <<
67 <<
68 (4) DCP <<
69 <<
70 Fixed set of cryptographic operations <<
71 environment. Only basic blob key encr <<
72 The actual key sealing/unsealing is d <<
73 <<
74 * Optional binding to platform integrity sta <<
75 <<
76 (1) TPM <<
77 <<
78 Keys can be optionally sealed to spec <<
79 values, and only unsealed by the TPM, <<
80 verifications match. A loaded Trusted <<
81 (future) PCR values, so keys are easi <<
82 such as when the kernel and initramfs <<
83 have many saved blobs under different <<
84 easily supported. <<
85 <<
86 (2) TEE <<
87 <<
88 Relies on Secure/Trusted boot process <<
89 be extended with TEE based measured b <<
90 <<
91 (3) CAAM <<
92 <<
93 Relies on the High Assurance Boot (HA <<
94 for platform integrity. <<
95 <<
96 (4) DCP <<
97 <<
98 Relies on Secure/Trusted boot process <<
99 platform integrity. <<
100 <<
101 * Interfaces and APIs <<
102 <<
103 (1) TPM <<
104 <<
105 TPMs have well-documented, standardiz <<
106 <<
107 (2) TEE <<
108 <<
109 TEEs have well-documented, standardiz <<
110 more details refer to ``Documentation <<
111 <<
112 (3) CAAM <<
113 <<
114 Interface is specific to silicon vend <<
115 <<
116 (4) DCP <<
117 <<
118 Vendor-specific API that is implement <<
119 ``drivers/crypto/mxs-dcp.c``. <<
120 <<
121 * Threat model <<
122 <<
123 The strength and appropriateness of a par <<
124 purpose must be assessed when using them <<
125 <<
126 <<
127 Key Generation <<
128 ============== <<
129 <<
130 Trusted Keys <<
131 ------------ <<
132 <<
133 New keys are created from random numbers. They <<
134 a child key in the storage key hierarchy. Encr <<
135 child key must be protected by a strong access <<
136 trust source. The random number generator in u <<
137 selected trust source: <<
138 <<
139 * TPM: hardware device based RNG <<
140 <<
141 Keys are generated within the TPM. Streng <<
142 from one device manufacturer to another. <<
143 <<
144 * TEE: OP-TEE based on Arm TrustZone based <<
145 <<
146 RNG is customizable as per platform needs <<
147 from platform specific hardware RNG or a <<
148 which can be seeded via multiple entropy <<
149 <<
150 * CAAM: Kernel RNG <<
151 <<
152 The normal kernel random number generator <<
153 CAAM HWRNG, enable CRYPTO_DEV_FSL_CAAM_RN <<
154 is probed. <<
155 <<
156 * DCP (Data Co-Processor: crypto accelerato <<
157 <<
158 The DCP hardware device itself does not p <<
159 so the kernel default RNG is used. SoCs w <<
160 a dedicated hardware RNG that is independ <<
161 to back the kernel RNG. <<
162 <<
163 Users may override this by specifying ``truste <<
164 command-line to override the used RNG with the <<
165 <<
166 Encrypted Keys <<
167 -------------- <<
168 <<
169 Encrypted keys do not depend on a trust source <<
170 for encryption/decryption. New keys are create <<
171 random numbers or user-provided decrypted data <<
172 using a specified ‘master’ key. The ‘mas <<
173 user-key type. The main disadvantage of encryp <<
174 rooted in a trusted key, they are only as secu <<
175 them. The master user key should therefore be <<
176 possible, preferably early in boot. <<
177 <<
178 <<
179 Usage <<
180 ===== <<
181 <<
182 Trusted Keys usage: TPM <<
183 ----------------------- <<
184 <<
185 TPM 1.2: By default, trusted keys are sealed u <<
186 default authorization value (20 bytes of 0s). <<
187 time with the TrouSerS utility: "tpm_takeowner <<
188 <<
189 TPM 2.0: The user must first create a storage <<
190 key is available after reboot. This can be don <<
191 33
192 With the IBM TSS 2 stack:: 34 With the IBM TSS 2 stack::
193 35
194 #> tsscreateprimary -hi o -st 36 #> tsscreateprimary -hi o -st
195 Handle 80000000 37 Handle 80000000
196 #> tssevictcontrol -hi o -ho 80000000 -hp 81 38 #> tssevictcontrol -hi o -ho 80000000 -hp 81000001
197 39
198 Or with the Intel TSS 2 stack:: 40 Or with the Intel TSS 2 stack::
199 41
200 #> tpm2_createprimary --hierarchy o -G rsa20 !! 42 #> tpm2_createprimary --hierarchy o -G rsa2048 -o key.ctxt
201 [...] 43 [...]
202 #> tpm2_evictcontrol -c key.ctxt 0x81000001 !! 44 handle: 0x800000FF
>> 45 #> tpm2_evictcontrol -c key.ctxt -p 0x81000001
203 persistentHandle: 0x81000001 46 persistentHandle: 0x81000001
204 47
205 Usage:: 48 Usage::
206 49
207 keyctl add trusted name "new keylen [optio 50 keyctl add trusted name "new keylen [options]" ring
208 keyctl add trusted name "load hex_blob [pc 51 keyctl add trusted name "load hex_blob [pcrlock=pcrnum]" ring
209 keyctl update key "update [options]" 52 keyctl update key "update [options]"
210 keyctl print keyid 53 keyctl print keyid
211 54
212 options: 55 options:
213 keyhandle= ascii hex value of sealin 56 keyhandle= ascii hex value of sealing key
214 TPM 1.2: default 0x4000 57 TPM 1.2: default 0x40000000 (SRK)
215 TPM 2.0: no default; mu 58 TPM 2.0: no default; must be passed every time
216 keyauth= ascii hex auth for sealin 59 keyauth= ascii hex auth for sealing key default 0x00...i
217 (40 ascii zeros) 60 (40 ascii zeros)
218 blobauth= ascii hex auth for sealed 61 blobauth= ascii hex auth for sealed data default 0x00...
219 (40 ascii zeros) 62 (40 ascii zeros)
220 pcrinfo= ascii hex of PCR_INFO or 63 pcrinfo= ascii hex of PCR_INFO or PCR_INFO_LONG (no default)
221 pcrlock= pcr number to be extended 64 pcrlock= pcr number to be extended to "lock" blob
222 migratable= 0|1 indicating permission 65 migratable= 0|1 indicating permission to reseal to new PCR values,
223 default 1 (resealing allo 66 default 1 (resealing allowed)
224 hash= hash algorithm name as a 67 hash= hash algorithm name as a string. For TPM 1.x the only
225 allowed value is sha1. Fo 68 allowed value is sha1. For TPM 2.x the allowed values
226 are sha1, sha256, sha384, 69 are sha1, sha256, sha384, sha512 and sm3-256.
227 policydigest= digest for the authorizat 70 policydigest= digest for the authorization policy. must be calculated
228 with the same hash algori 71 with the same hash algorithm as specified by the 'hash='
229 option. 72 option.
230 policyhandle= handle to an authorizatio 73 policyhandle= handle to an authorization policy session that defines the
231 same policy and with the 74 same policy and with the same hash algorithm as was used to
232 seal the key. 75 seal the key.
233 76
234 "keyctl print" returns an ascii hex copy of th 77 "keyctl print" returns an ascii hex copy of the sealed key, which is in standard
235 TPM_STORED_DATA format. The key length for ne 78 TPM_STORED_DATA format. The key length for new keys are always in bytes.
236 Trusted Keys can be 32 - 128 bytes (256 - 1024 79 Trusted Keys can be 32 - 128 bytes (256 - 1024 bits), the upper limit is to fit
237 within the 2048 bit SRK (RSA) keylength, with 80 within the 2048 bit SRK (RSA) keylength, with all necessary structure/padding.
238 81
239 Trusted Keys usage: TEE !! 82 Encrypted keys do not depend on a TPM, and are faster, as they use AES for
240 ----------------------- !! 83 encryption/decryption. New keys are created from kernel generated random
241 !! 84 numbers, and are encrypted/decrypted using a specified 'master' key. The
242 Usage:: !! 85 'master' key can either be a trusted-key or user-key type. The main
243 !! 86 disadvantage of encrypted keys is that if they are not rooted in a trusted key,
244 keyctl add trusted name "new keylen" ring !! 87 they are only as secure as the user key encrypting them. The master user key
245 keyctl add trusted name "load hex_blob" ri !! 88 should therefore be loaded in as secure a way as possible, preferably early in
246 keyctl print keyid !! 89 boot.
247 <<
248 "keyctl print" returns an ASCII hex copy of th <<
249 specific to TEE device implementation. The ke <<
250 in bytes. Trusted Keys can be 32 - 128 bytes ( <<
251 <<
252 Trusted Keys usage: CAAM <<
253 ------------------------ <<
254 <<
255 Usage:: <<
256 <<
257 keyctl add trusted name "new keylen" ring <<
258 keyctl add trusted name "load hex_blob" ri <<
259 keyctl print keyid <<
260 <<
261 "keyctl print" returns an ASCII hex copy of th <<
262 CAAM-specific format. The key length for new <<
263 Trusted Keys can be 32 - 128 bytes (256 - 1024 <<
264 <<
265 Trusted Keys usage: DCP <<
266 ----------------------- <<
267 <<
268 Usage:: <<
269 <<
270 keyctl add trusted name "new keylen" ring <<
271 keyctl add trusted name "load hex_blob" ri <<
272 keyctl print keyid <<
273 <<
274 "keyctl print" returns an ASCII hex copy of th <<
275 specific to this DCP key-blob implementation. <<
276 always in bytes. Trusted Keys can be 32 - 128 <<
277 <<
278 Encrypted Keys usage <<
279 -------------------- <<
280 90
281 The decrypted portion of encrypted keys can co 91 The decrypted portion of encrypted keys can contain either a simple symmetric
282 key or a more complex structure. The format of 92 key or a more complex structure. The format of the more complex structure is
283 application specific, which is identified by ' 93 application specific, which is identified by 'format'.
284 94
285 Usage:: 95 Usage::
286 96
287 keyctl add encrypted name "new [format] ke 97 keyctl add encrypted name "new [format] key-type:master-key-name keylen"
288 ring 98 ring
289 keyctl add encrypted name "new [format] ke <<
290 decrypted-data" ring <<
291 keyctl add encrypted name "load hex_blob" 99 keyctl add encrypted name "load hex_blob" ring
292 keyctl update keyid "update key-type:maste 100 keyctl update keyid "update key-type:master-key-name"
293 101
294 Where:: 102 Where::
295 103
296 format:= 'default | ecryptfs | enc32' 104 format:= 'default | ecryptfs | enc32'
297 key-type:= 'trusted' | 'user' 105 key-type:= 'trusted' | 'user'
298 106
299 Examples of trusted and encrypted key usage <<
300 ------------------------------------------- <<
301 107
302 Create and save a trusted key named "kmk" of l !! 108 Examples of trusted and encrypted key usage:
>> 109
>> 110 Create and save a trusted key named "kmk" of length 32 bytes::
303 111
304 Note: When using a TPM 2.0 with a persistent k 112 Note: When using a TPM 2.0 with a persistent key with handle 0x81000001,
305 append 'keyhandle=0x81000001' to statements be 113 append 'keyhandle=0x81000001' to statements between quotes, such as
306 "new 32 keyhandle=0x81000001". 114 "new 32 keyhandle=0x81000001".
307 115
308 :: <<
309 <<
310 $ keyctl add trusted kmk "new 32" @u 116 $ keyctl add trusted kmk "new 32" @u
311 440502848 117 440502848
312 118
313 $ keyctl show 119 $ keyctl show
314 Session Keyring 120 Session Keyring
315 -3 --alswrv 500 500 keyring: 121 -3 --alswrv 500 500 keyring: _ses
316 97833714 --alswrv 500 -1 \_ keyri 122 97833714 --alswrv 500 -1 \_ keyring: _uid.500
317 440502848 --alswrv 500 500 \_ t 123 440502848 --alswrv 500 500 \_ trusted: kmk
318 124
319 $ keyctl print 440502848 125 $ keyctl print 440502848
320 0101000000000000000001005d01b7e3f4a6be5709 126 0101000000000000000001005d01b7e3f4a6be5709930f3b70a743cbb42e0cc95e18e915
321 3f60da455bbf1144ad12e4f92b452f966929f6105f 127 3f60da455bbf1144ad12e4f92b452f966929f6105fd29ca28e4d4d5a031d068478bacb0b
322 27351119f822911b0a11ba3d3498ba6a32e50dac7f 128 27351119f822911b0a11ba3d3498ba6a32e50dac7f32894dd890eb9ad578e4e292c83722
323 a52e56a097e6a68b3f56f7a52ece0cdccba1eb62ca 129 a52e56a097e6a68b3f56f7a52ece0cdccba1eb62cad7d817f6dc58898b3ac15f36026fec
324 d568bd4a706cb60bb37be6d8f1240661199d640b66 130 d568bd4a706cb60bb37be6d8f1240661199d640b66fb0fe3b079f97f450b9ef9c22c6d5d
325 dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471 131 dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471dc6d13ecf8298b946f65345faa5ef0
326 f1f8fff03ad0acb083725535636addb08d73dedb98 132 f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b
327 e4a8aea2b607ec96931e6f4d4fe563ba 133 e4a8aea2b607ec96931e6f4d4fe563ba
328 134
329 $ keyctl pipe 440502848 > kmk.blob 135 $ keyctl pipe 440502848 > kmk.blob
330 136
331 Load a trusted key from the saved blob:: 137 Load a trusted key from the saved blob::
332 138
333 $ keyctl add trusted kmk "load `cat kmk.bl 139 $ keyctl add trusted kmk "load `cat kmk.blob`" @u
334 268728824 140 268728824
335 141
336 $ keyctl print 268728824 142 $ keyctl print 268728824
337 0101000000000000000001005d01b7e3f4a6be5709 143 0101000000000000000001005d01b7e3f4a6be5709930f3b70a743cbb42e0cc95e18e915
338 3f60da455bbf1144ad12e4f92b452f966929f6105f 144 3f60da455bbf1144ad12e4f92b452f966929f6105fd29ca28e4d4d5a031d068478bacb0b
339 27351119f822911b0a11ba3d3498ba6a32e50dac7f 145 27351119f822911b0a11ba3d3498ba6a32e50dac7f32894dd890eb9ad578e4e292c83722
340 a52e56a097e6a68b3f56f7a52ece0cdccba1eb62ca 146 a52e56a097e6a68b3f56f7a52ece0cdccba1eb62cad7d817f6dc58898b3ac15f36026fec
341 d568bd4a706cb60bb37be6d8f1240661199d640b66 147 d568bd4a706cb60bb37be6d8f1240661199d640b66fb0fe3b079f97f450b9ef9c22c6d5d
342 dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471 148 dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471dc6d13ecf8298b946f65345faa5ef0
343 f1f8fff03ad0acb083725535636addb08d73dedb98 149 f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b
344 e4a8aea2b607ec96931e6f4d4fe563ba 150 e4a8aea2b607ec96931e6f4d4fe563ba
345 151
346 Reseal (TPM specific) a trusted key under new !! 152 Reseal a trusted key under new pcr values::
347 153
348 $ keyctl update 268728824 "update pcrinfo= 154 $ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`"
349 $ keyctl print 268728824 155 $ keyctl print 268728824
350 010100000000002c0002800093c35a09b70fff26e7 156 010100000000002c0002800093c35a09b70fff26e7a98ae786c641e678ec6ffb6b46d805
351 77c8a6377aed9d3219c6dfec4b23ffe3000001005d 157 77c8a6377aed9d3219c6dfec4b23ffe3000001005d37d472ac8a44023fbb3d18583a4f73
352 d3a076c0858f6f1dcaa39ea0f119911ff03f5406df 158 d3a076c0858f6f1dcaa39ea0f119911ff03f5406df4f7f27f41da8d7194f45c9f4e00f2e
353 df449f266253aa3f52e55c53de147773e00f0f9aca 159 df449f266253aa3f52e55c53de147773e00f0f9aca86c64d94c95382265968c354c5eab4
354 9638c5ae99c89de1e0997242edfb0b501744e11ff9 160 9638c5ae99c89de1e0997242edfb0b501744e11ff9762dfd951cffd93227cc513384e7e6
355 e782c29435c7ec2edafaa2f4c1fe6e7a781b59549f 161 e782c29435c7ec2edafaa2f4c1fe6e7a781b59549ff5296371b42133777dcc5b8b971610
356 94bc67ede19e43ddb9dc2baacad374a36feaf0314d 162 94bc67ede19e43ddb9dc2baacad374a36feaf0314d700af0a65c164b7082401740e489c9
357 7ef6a24defe4846104209bf0c3eced7fa1a672ed5b 163 7ef6a24defe4846104209bf0c3eced7fa1a672ed5b125fc9d8cd88b476a658a4434644ef
358 df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f 164 df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f06b3b8
359 165
360 <<
361 The initial consumer of trusted keys is EVM, w 166 The initial consumer of trusted keys is EVM, which at boot time needs a high
362 quality symmetric key for HMAC protection of f !! 167 quality symmetric key for HMAC protection of file metadata. The use of a
363 trusted key provides strong guarantees that th 168 trusted key provides strong guarantees that the EVM key has not been
364 compromised by a user level problem, and when !! 169 compromised by a user level problem, and when sealed to specific boot PCR
365 state, protects against boot and offline attac !! 170 values, protects against boot and offline attacks. Create and save an
366 encrypted key "evm" using the above trusted ke 171 encrypted key "evm" using the above trusted key "kmk":
367 172
368 option 1: omitting 'format':: 173 option 1: omitting 'format'::
369 174
370 $ keyctl add encrypted evm "new trusted:km 175 $ keyctl add encrypted evm "new trusted:kmk 32" @u
371 159771175 176 159771175
372 177
373 option 2: explicitly defining 'format' as 'def 178 option 2: explicitly defining 'format' as 'default'::
374 179
375 $ keyctl add encrypted evm "new default tr 180 $ keyctl add encrypted evm "new default trusted:kmk 32" @u
376 159771175 181 159771175
377 182
378 $ keyctl print 159771175 183 $ keyctl print 159771175
379 default trusted:kmk 32 2375725ad57798846a9 184 default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3
380 82dbbc55be2a44616e4959430436dc4f2a7a9659aa 185 82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0
381 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc 186 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc
382 187
383 $ keyctl pipe 159771175 > evm.blob 188 $ keyctl pipe 159771175 > evm.blob
384 189
385 Load an encrypted key "evm" from saved blob:: 190 Load an encrypted key "evm" from saved blob::
386 191
387 $ keyctl add encrypted evm "load `cat evm. 192 $ keyctl add encrypted evm "load `cat evm.blob`" @u
388 831684262 193 831684262
389 194
390 $ keyctl print 831684262 195 $ keyctl print 831684262
391 default trusted:kmk 32 2375725ad57798846a9 196 default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3
392 82dbbc55be2a44616e4959430436dc4f2a7a9659aa 197 82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0
393 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc 198 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc
394 199
395 Instantiate an encrypted key "evm" using user- <<
396 <<
397 $ evmkey=$(dd if=/dev/urandom bs=1 count=3 <<
398 $ keyctl add encrypted evm "new default us <<
399 794890253 <<
400 <<
401 $ keyctl print 794890253 <<
402 default user:kmk 32 2375725ad57798846a9bbd <<
403 bbc55be2a44616e4959430436dc4f2a7a9659aa60b <<
404 17c64 5972dcb82ab2dde83376d82b2e3c09ffc <<
405 <<
406 Other uses for trusted and encrypted keys, suc 200 Other uses for trusted and encrypted keys, such as for disk and file encryption
407 are anticipated. In particular the new format !! 201 are anticipated. In particular the new format 'ecryptfs' has been defined in
408 in order to use encrypted keys to mount an eCr 202 in order to use encrypted keys to mount an eCryptfs filesystem. More details
409 about the usage can be found in the file 203 about the usage can be found in the file
410 ``Documentation/security/keys/ecryptfs.rst``. 204 ``Documentation/security/keys/ecryptfs.rst``.
411 205
412 Another new format 'enc32' has been defined in 206 Another new format 'enc32' has been defined in order to support encrypted keys
413 with payload size of 32 bytes. This will initi 207 with payload size of 32 bytes. This will initially be used for nvdimm security
414 but may expand to other usages that require 32 208 but may expand to other usages that require 32 bytes payload.
415 <<
416 <<
417 TPM 2.0 ASN.1 Key Format <<
418 ------------------------ <<
419 <<
420 The TPM 2.0 ASN.1 key format is designed to be <<
421 even in binary form (fixing a problem we had w <<
422 format) and to be extensible for additions lik <<
423 policy:: <<
424 <<
425 TPMKey ::= SEQUENCE { <<
426 type OBJECT IDENTIFIER <<
427 emptyAuth [0] EXPLICIT BOOLEAN O <<
428 parent INTEGER <<
429 pubkey OCTET STRING <<
430 privkey OCTET STRING <<
431 } <<
432 <<
433 type is what distinguishes the key even in bin <<
434 is provided by the TCG to be unique and thus f <<
435 binary pattern at offset 3 in the key. The OI <<
436 available are:: <<
437 <<
438 2.23.133.10.1.3 TPM Loadable key. This is <<
439 RSA2048 or Elliptic Curve) <<
440 TPM2_Load() operation. <<
441 <<
442 2.23.133.10.1.4 TPM Importable Key. This <<
443 RSA2048 or Elliptic Curve) <<
444 TPM2_Import() operation. <<
445 <<
446 2.23.133.10.1.5 TPM Sealed Data. This is <<
447 bytes) which is sealed by <<
448 represents a symmetric key <<
449 use. <<
450 <<
451 The trusted key code only uses the TPM Sealed <<
452 <<
453 emptyAuth is true if the key has well known au <<
454 is false or not present, the key requires an e <<
455 phrase. This is used by most user space consu <<
456 to prompt for a password. <<
457 <<
458 parent represents the parent key handle, eithe <<
459 like 0x81000001 for the RSA primary storage ke <<
460 also support specifying the primary handle in <<
461 this happens the Elliptic Curve variant of the <<
462 TCG defined template will be generated on the <<
463 object and used as the parent. The current ke <<
464 the 0x81 MSO form. <<
465 <<
466 pubkey is the binary representation of TPM2B_P <<
467 initial TPM2B header, which can be reconstruct <<
468 string length. <<
469 <<
470 privkey is the binary representation of TPM2B_ <<
471 initial TPM2B header which can be reconstructe <<
472 string length. <<
473 <<
474 DCP Blob Format <<
475 --------------- <<
476 <<
477 .. kernel-doc:: security/keys/trusted-keys/tru <<
478 :doc: dcp blob format <<
479 <<
480 .. kernel-doc:: security/keys/trusted-keys/tru <<
481 :identifiers: struct dcp_blob_fmt <<
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