Section: General Commands Manual (1)
Updated: SEPTEMBER 2017
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tpm2_certify(1) - prove that an object is loaded in the tpm.  


tpm2_certify [OPTIONS]  


tpm2_certify(1) proves that an object with a specific NAME is loaded in the TPM. By certifying that the object is loaded, the TPM warrants that a public area with a given NAME is self-consistent and associated with a valid sensitive area. If a relying party has a public area that has the same NAME as a NAME certified with this command, then the values in that public area are correct. The object may be any object that is loaded with TPM2_Load() or TPM2_CreatePrimary(). An object that only has its public area loaded cannot be certified.  


These options control the ceritifcation:

-H, -obj-handle=OBJECT_HANDLE: The handle of the object to be certified.
-C, -obj-context=FILE: Use FILE for providing the object context.
-k, -key-handle=KEY_HANDLE: Handle of the key used to sign the attestation structure.
-c, -key-context=KEY_CONTEXT: Filename of the key context used to sign the attestation structure.
-P, -pwdo=OBJECT_PASSWORD: Use OBJECT_PASSWORD for providing an authorization value for the object specified in OBJECT_HANDLE. Passwords should follow the "password formatting standards, see section"Password Formatting“.
-K, -pwdk=KEY_PASSWORD: Use KEY_PASSWORD for providing an authorization value for the key specified in KEY_HANDLE. Follows the same formatting guidelines as the object handle password or -P option.
-a, -attest-file=ATTEST_FILE: Output file name for the attestation data.
-s, -sig-file=SIG_FILE: Output file name for the signature data.
-f, -format

Format selection for the signature output file. See section "Signature Format Specifiers".



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

-h, -help: Display the tools manpage. This requires the manpages to be installed or on MANPATH, See man(1) for more details.
-v, -version: Display version information for this tool, supported tctis and exit.
-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.
-Q, -quiet: Silence normal tool output to stdout.
-Z, -enable-errata: Enable the application of errata fixups. Useful if an errata fixup needs to be applied to commands sent to the TPM. # TCTI ENVIRONMENT

This collection of environment variables that may be used to configure the various TCTI modules available.

The values passed through these variables can be overridden on a per-command basis using the available command line options, see the TCTI_OPTIONS section.

The variables respected depend on how the software was configured.

TPM2TOOLS_TCTI_NAME: Select the TCTI used for communication with the next component down the TSS stack. In most configurations this will be the TPM but it could be a simulator or proxy. The current known TCTIs are:
tabrmd - The new resource manager, called tabrmd (
socket - Typically used with the old resource manager, or talking directly to a simulator.
device - Used when talking directly to a TPM device file.
TPM2TOOLS_DEVICE_FILE: When using the device TCTI, specify the TPM device file. The default is "/dev/tpm0".

Note: Using the tpm directly requires the users to ensure that concurrent access does not occur and that they manage the tpm resources. These tasks are usually managed by a resource manager. Linux 4.12 and greater supports an in kernel resource manager at "/dev/tpmrm", typically "/dev/tpmrm0".

TPM2TOOLS_SOCKET_ADDRESS: When using the socket TCTI, specify the domain name or IP address used. The default is
TPM2TOOLS_SOCKET_PORT: When using the socket TCTI, specify the port number used. The default is 2321.


This collection of options are used to configure the varous TCTI modules available. They override any environment variables.

-T, -tcti=TCTI_NAME[:TCTI_OPTIONS]: Select the TCTI used for communication with the next component down the TSS stack. In most configurations this will be the resource manager: tabrmd ( Optionally, tcti specific options can appended to TCTI_NAME by appending a : to TCTI_NAME.
For the device TCTI, the TPM device file for use by the device TCTI can be specified. The default is /dev/tpm0. Example: -T device:/dev/tpm0
For the socket TCTI, the domain name or IP address and port number used by the socket can be specified. The default are and 2321. Example: -T socket:
For the abrmd TCTI, it takes no options. Example: -T abrmd

Password Formatting

Passwords are interpreted in two forms, string and hex-string. A string password is not interpreted, and is directly used for authorization. A hex-string, is converted from a hexidecimal form into a byte array form, thus allowing passwords with non-printable and/or terminal un-friendly characters.

By default passwords are assumed to be in the string form. Password form is specified with special prefix values, they are:

str: - Used to indicate it is a raw string. Useful for escaping a password that starts with the "hex:" prefix.
hex: - Used when specifying a password in hex string format.

Signature Format Specifiers

Format selection for the signature output file. tss (the default) will output a binary blob according to the TPM 2.0 specification and any potential compiler padding. The option plain will output the plain signature data as defined by the used cryptographic algorithm. # EXAMPLES

tpm2_certify -H 0x81010002 -k 0x81010001 -P 0x0011 -K 0x00FF -g 0x00B -a <fileName> -s <fileName>
tpm2_certify -C obj.context -c key.context -P 0x0011 -K 0x00FF -g 0x00B -a <fileName> -s <fileName>
tpm2_certify -H 0x81010002 -k 0x81010001 -P 0011 -K 00FF -X -g 0x00B -a <fileName> -s <fileName>



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Password Formatting
Signature Format Specifiers