tpm2_policyduplicationselect - Man Page

Restricts duplication to a specific new parent.


tpm2_policyduplicationselect [Options]


tpm2_policyduplicationselect(1) - Restricts duplication to a specific new parent.



Common Options

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

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 variable.

The current known TCTIs are:

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-option-config> results in the default being used for that portion respectively.

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 indicate 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 library name as understood by dlopen(3) semantics.

Tcti Options

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


Setup a duplication role policy to restricted new parent

Create source parent and destination(or new) parent

tpm2_createprimary -C n -g sha256 -G rsa -c dst_n.ctx -Q
tpm2_createprimary -C o -g sha256 -G rsa -c src_o.ctx -Q

Create the restricted parent policy

tpm2_readpublic -c dst_n.ctx -n -Q
tpm2_startauthsession -S session.ctx
tpm2_policyduplicationselect -S session.ctx  -N \
-L policydupselect.dat -Q
tpm2_flushcontext session.ctx
rm session.ctx

Create the object to be duplicated using the policy

tpm2_create -C src_o.ctx -g sha256 -G rsa -r dupkey.priv -u \
-L policydupselect.dat  -a "sensitivedataorigin|sign|decrypt" -c dupkey.ctx -Q
tpm2_readpublic -c dupkey.ctx -n -Q

Satisfy the policy and duplicate the object

tpm2_startauthsession -S session.ctx --policy-session
tpm2_policyduplicationselect -S session.ctx  -N -n -Q
tpm2_duplicate -C dst_n.ctx -c dupkey.ctx -G null -p session:session.ctx \
-r new_dupkey.priv -s dupseed.dat
tpm2_flushcontext  session.ctx
rm session.ctx



Tools can return any of the following codes:


It expects a session to be already established via tpm2_startauthsession(1) and requires one of the following:

Without it, most resource managers will not save session state between command invocations.


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tpm2-tools General Commands Manual