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tpm2_pcrread(1)		    General Commands Manual	       tpm2_pcrread(1)

       tpm2_pcrread(1) - List PCR values.

       tpm2_pcrread [OPTIONS] PCR_LIST_OR_ALG

       tpm2_pcrread(1)	 -   Displays  PCR  values.   Without  any  arguments,
       tpm2_pcrread(1) outputs all PCRs	and their hash	banks.	 One  can  use
       specify	the  hash algorithm or a pcr list as an	argument to filter the

       To only output PCR banks	with a given algorithm,	 specify  the  hashing
       algorithm  as  the  argument.  Algorithms should	follow the "formatting
       standards", see section	"Algorithm  Specifiers".   Also,  see  section
       "Supported Hash Algorithms" for a list of supported hash	algorithms.

       To output a list	of PCR banks (sha1, sha256, etc) and ids (0, 1,	2 etc)
       specify a PCR selection list as the argument as specified  via  section
       "PCR Bank Specifiers".

       Also read NOTES section below.

       Output  is written in a YAML format to stdout, with each	algorithm fol-
       lowed by	a PCR index and	its value.  As a simple	 example  assume  just
       sha1 and	sha256 support and only	1 PCR.	The output would be:

	      $	tpm2_pcrread sha1:0+sha256:0
	      sha1 :
		0  : 0000000000000000000000000000000000000003
	      sha256 :
		0  : 0000000000000000000000000000000000000000000000000000000000000003

       o -o, --output=FILE:

	 The output file to write the PCR values in binary format, optional.

       This  collection	of options are common to many programs and provide in-
       formation that many users may expect.

       o -h, --help=[man|no-man]: Display the tools manpage.  By  default,  it
	 attempts  to  invoke  the  manpager for the tool, however, on failure
	 will output a short tool summary.  This is the	same behavior  if  the
	 "man"	option argument	is specified, however if explicit "man"	is re-
	 quested, the tool will	provide	errors from man	 on  stderr.   If  the
	 "no-man"  option  if  specified, or the manpager fails, the short op-
	 tions will be output to stdout.

	 To successfully use the manpages feature requires the manpages	to  be
	 installed or on MANPATH, See man(1) for more details.

       o -v,  --version:  Display version information for this tool, supported
	 tctis and exit.

       o -V, --verbose:	Increase the information that the tool prints  to  the
	 console  during  its  execution.  When	using this option the file and
	 line number are printed.

       o -Q, --quiet: Silence normal tool output to stdout.

       o -Z, --enable-errata: Enable the application of	errata fixups.	Useful
	 if  an	 errata	fixup needs to be applied to commands sent to the TPM.
	 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.

TCTI Configuration
       The TCTI	or "Transmission Interface"  is	 the  communication  mechanism
       with  the TPM.  TCTIs can be changed for	communication with TPMs	across
       different mediums.

       To control the TCTI, the	tools respect:

       1. The command line option -T or	--tcti

       2. The environment variable: TPM2TOOLS_TCTI.

       Note: The command line option always overrides  the  environment	 vari-

       The current known TCTIs are:

       o tabrmd	     -	   The	   resource	manager,     called	tabrmd
	 (	 Note that tabrmd  and
	 abrmd as a tcti name are synonymous.

       o mssim	- Typically used for communicating to the TPM software simula-

       o device	- Used when talking directly to	a TPM device file.

       o none -	Do not initalize a connection with the TPM.  Some tools	 allow
	 for off-tpm options and thus support not using	a TCTI.	 Tools that do
	 not support it	will error when	attempted to be	used  without  a  TCTI
	 connection.   Does  not  support ANY options and MUST BE presented as
	 the exact text	of "none".

       The arguments to	either the command  line  option  or  the  environment
       variable	are in the form:


       Specifying  an  empty  string  for  either the <tcti-name> or <tcti-op-
       tion-config> results in the default being used for that portion respec-

   TCTI	Defaults
       When  a	TCTI  is not specified,	the default TCTI is searched for using
       dlopen(3) semantics.  The tools will  search  for  tabrmd,  device  and
       mssim  TCTIs  IN	THAT ORDER and USE THE FIRST ONE FOUND.	 You can query
       what TCTI will be chosen	as the default by using	the -v option to print
       the  version information.  The "default-tcti" key-value pair will indi-
       cate which of the aforementioned	TCTIs is the default.

   Custom TCTIs
       Any TCTI	that implements	the dynamic TCTI interface can be loaded.  The
       tools internally	use dlopen(3), and the raw tcti-name value is used for
       the lookup.  Thus, this could be	a path to the shared library, or a li-
       brary name as understood	by dlopen(3) semantics.

       This collection of options are used to configure	the various known TCTI
       modules available:

       o device: For the device	TCTI, the TPM character	device file for	use by
	 the device TCTI can be	specified.  The	default	is /dev/tpm0.

	 Example:    -T	  device:/dev/tpm0   or	  export   TPM2TOOLS_TCTI="de-

       _o mssim:	For the	mssim TCTI, the	domain name or	IP  address  and  port
	 number	 used  by  the	simulator  can	be specified.  The default are and 2321.

	 Example: -T mssim:host=localhost,port=2321  or	 export	 TPM2TOOLS_TC-

       _o abrmd:	 For  the abrmd	TCTI, the configuration	string format is a se-
	 ries of simple	key value pairs	separated by a	','  character.	  Each
	 key and value string are separated by a '=' character.

	 o TCTI	abrmd supports two keys:

	   1. 'bus_name'  :  The  name	of  the	 tabrmd	 service on the	bus (a

	   2. 'bus_type' : The type of the dbus	instance (a string) limited to
	      'session'	and 'system'.

	 Specify  the tabrmd tcti name and a config string of bus_name=com.ex-


	 Specify the default (abrmd) tcti and a	config string of bus_type=ses-


	 NOTE: abrmd and tabrmd	are synonymous.

       PCR bank	specifiers (common/

Supported Hash Algorithms
       Supported hash algorithms are:

       o 0x4 or	sha1 for TPM_ALG_SHA1 (default)

       o 0xB or	sha256 for TPM_ALG_SHA256

       o 0xC or	sha384 for TPM_ALG_SHA384

       o 0xD or	sha512 for TPM_ALG_SHA512

       o 0x12 or sm3_256 for TPM_ALG_SM3_256

       NOTE: Your TPM may not support all algorithms.

Algorithm Specifiers
       Options that take algorithms support "nice-names".

       There  are two major algorithm specification string classes, simple and
       complex.	 Only certain algorithms will be accepted by the TPM, based on
       usage and conditions.

   Simple specifiers
       These are strings with no additional specification data.	 When creating
       objects,	non-specified portions of an object are	assumed	 to  defaults.
       You can find the	list of	known "Simple Specifiers Below".

       o rsa

       o ecc

       o aes

       o camellia

   Hashing Algorithms
       o sha1

       o sha256

       o sha384

       o sha512

       o sm3_256

       o sha3_256

       o sha3_384

       o sha3_512

   Keyed Hash
       o hmac

       o xor

   Signing Schemes
       o rsassa

       o rsapss

       o ecdsa

       o ecdaa

       o ecschnorr

   Asymmetric Encryption Schemes
       o oaep

       o rsaes

       o ecdh

       o ctr

       o ofb

       o cbc

       o cfb

       o ecb

       o null

   Complex Specifiers
       Objects,	 when  specified  for creation by the TPM, have	numerous algo-
       rithms to populate in the public	data.  Things like  type,  scheme  and
       asymmetric  details,  key  size,	 etc.  Below is	the general format for
       specifying this data: <type>:<scheme>:<symmetric-details>

   Type	Specifiers
       This portion of the complex algorithm specifier is required.   The  re-
       maining	scheme	and  symmetric	details	will default based on the type
       specified and the type of the object being created.

       o aes - Default AES: aes128

       o aes128<mode> -	128 bit	AES with optional mode	(ctr|ofb|cbc|cfb|ecb).
	 If mode is not	specified, defaults to null.

       o aes192<mode> -	Same as	aes128<mode>, except for a 192 bit key size.

       o aes256<mode> -	Same as	aes128<mode>, except for a 256 bit key size.

       o ecc - Elliptical Curve, defaults to ecc256.

       o ecc192	- 192 bit ECC

       o ecc224	- 224 bit ECC

       o ecc256	- 256 bit ECC

       o ecc384	- 384 bit ECC

       o ecc521	- 521 bit ECC

       o rsa - Default RSA: rsa2048

       o rsa1024 - RSA with 1024 bit keysize.

       o rsa2048 - RSA with 2048 bit keysize.

       o rsa4096 - RSA with 4096 bit keysize.

   Scheme Specifiers
       Next, is	an optional field, it can be skipped.

       Schemes	are  usually Signing Schemes or	Asymmetric Encryption Schemes.
       Most signing schemes take a hash	algorithm directly following the sign-
       ing  scheme.   If the hash algorithm is missing,	it defaults to sha256.
       Some take no arguments, and some	take multiple arguments.

   Hash	Optional Scheme	Specifiers
       These scheme specifiers are followed by a dash and a valid  hash	 algo-
       rithm, For example: oaep-sha256.

       o oaep

       o ecdh

       o rsassa

       o rsapss

       o ecdsa

       o ecschnorr

   Multiple Option Scheme Specifiers
       This  scheme  specifier	is  followed by	a count	(max size UINT16) then
       folloed by a dash(-) and	a valid	hash algorithm.	 * ecdaa For  example,
       ecdaa4-sha256.  If no count is specified, it defaults to	4.

   No Option Scheme Specifiers
       This scheme specifier takes NO arguments.  * rsaes

   Symmetric Details Specifiers
       This  field is optional,	and defaults based on the type of object being
       created and it's	attributes.  Generally,	any valid Symmetric  specifier
       from  the Type Specifiers list should work.  If not specified, an asym-
       metric objects symmetric	details	defaults to aes128cfb.

   Create an rsa2048 key with an rsaes asymmetric encryption scheme
       tpm2_create -C parent.ctx -G rsa2048:rsaes -u -r	key.priv

   Create an ecc256 key	with an	ecdaa signing scheme with a count of 4
       and sha384 hash

       /tpm2_create -C parent.ctx -G ecc256:ec-
       daa4-sha384 -u -r key.priv

   Display all PCR values

   Display the PCR values with a specified bank
	      tpm2_pcrread sha1

   Display the PCR values with specified banks and store in a file
	      tpm2_pcrread -o pcrs sha1:16,17,18+sha256:16,17,18

   Display the supported PCR bank algorithms and exit

       The maximum number of PCR that can be dumped at once is associated with
       the maximum length of a bank.

       On most TPMs, it	means that this	tool can dump up to 24 PCRs at once.

       Tools can return	any of the following codes:

       o 0 - Success.

       o 1 - General non-specific error.

       o 2 - Options handling error.

       o 3 - Authentication error.

       o 4 - TCTI related error.

       o 5 - Non supported scheme.  Applicable to tpm2_testparams.

       Github Issues (

       See the Mailing List (

tpm2-tools						       tpm2_pcrread(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | COMMON OPTIONS | TCTI Configuration | TCTI OPTIONS | Supported Hash Algorithms | Algorithm Specifiers | EXAMPLES | NOTES | Returns | BUGS | HELP

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