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tpm2_getrandom(1) General Commands Manual tpm2_getrandom(1)

NAME

tpm2_getrandom(1) - Retrieves random bytes from the TPM.

SYNOPSIS

tpm2_getrandom [OPTIONS] SIZE

DESCRIPTION

tpm2_getrandom(1) - Returns the next SIZE octets from the random number generator. The SIZE parameter is expected as the only argument to the tool.

OPTIONS

•
-o, –output=FILE specifies the filename to output the raw bytes to. Defaults to stdout as a hex string.

COMMON OPTIONS

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 (https://github.com/01org/tpm2-abrmd).
•
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 127.0.0.1.
•
TPM2TOOLS_SOCKET_PORT: When using the socket TCTI, specify the port number used. The default is 2321.

TCTI OPTIONS

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 (https://github.com/01org/tpm2-abrmd) 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 127.0.0.1 and 2321. Example: -T socket:127.0.0.1:2321
•
For the abrmd TCTI, it takes no options. Example: -T abrmd

EXAMPLES

Generate a random 20 bytes and output the binary data to a file:

tpm2_getrandom -o random.out 20

Generate a random 8 bytes and output the hex formated data to stdout:

tpm2_getrandom 8

RETURNS

0 on success or 1 on failure.

BUGS

Github Issues (https://github.com/01org/tpm2-tools/issues)

HELP

See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)

SEPTEMBER 2017 tpm2-tools