Section: General Commands Manual (1)
Updated: SEPTEMBER 2017
Page Index


tpm2_nvdefine(1) - define a TPM Non-Volatile (NV) index.  


tpm2_nvdefine [OPTIONS]  


tpm2_nvdefine(1) - Define NV index with given auth value.  


-x, -index=NV_INDEX: Specifies the index to define the space at.
-a, -auth-handle=SECRET_DATA_FILE: specifies the handle used to authorize:
0x40000001 for TPM_RH_OWNER
0x4000000C for TPM_RH_PLATFORM
-s, -size=SIZE: specifies the size of data area in bytes. Defaults to MAX_NV_INDEX_SIZE which is typically 2048.
-t, -attributes=ATTRIBUTES Specifies the attribute values for the nv region used when creating the entitiy. Either the raw bitfield mask or "nice-names" may be used. See section "NV Attributes" for more details.
-P, -handle-passwd=HANDLE_PASSWORD: specifies the password of authHandle. Passwords should follow the "password formatting standards, see section"Password Formatting“.
-I, -index-passwd=INDEX_PASSWORD: specifies the password of NV Index when created. Follows the same formatting guidelines as the handle password or -P option.
-L, -policy-file=POLICY_FILE: Specifies the policy digest file for policy based authorizations.
-S, -input-session-handle=SIZE: Optional Input session handle from a policy session for authorization.


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

NV Attributes

NV Attributes are used to control various properties of the NV defined space. When specified as an option, either the raw bitfield mask or "nice-names" may be used. The values can be found in Table 204 Part 2 of the TPM2.0 specification, which can be found here:


Nice names are calculated by taking the name field of table 204 and removing the prefix TPMA_NV_ and lowercasing the result. Thus, TPMA_NV_PPWRITE becomes ppwrite. Nice names can be joined using the bitwise or "|" symbol.

Note that the TPM_NT field is 4 bits wide, and thus can be set via nt= format. For instance, to set The fields TPMA_NV_OWNERREAD, TPMA_NV_OWNERWRITE, TPMA_NV_POLICYWRITE, and TPMA_NT = 0x3, the argument would be:

ownerread|ownerwrite|policywrite|nt=0x3 # 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.


tpm2_nvdefine -x 0x1500016 -a 0x40000001 -s 32 -t 0x2000A
tpm2_nvdefine -x 0x1500016 -a 0x40000001 -s 32 -t ownerread|ownerwrite|policywrite -I 1a1b1c



0 on success or 1 on failure.  


Github Issues (  


See the Mailing List (



NV Attributes