tpm2_incrementalselftest man page

tpm2_incrementalselftest(1) — Request testing of specified algorithm list

Synopsis

tpm2_incrementalselftest [Options] Alg_spec_list

Description

tpm2_incrementalselftest(1) Request the TPM to perform testing on specified algorithm and print a list of algorithm scheduled to be tested OR remain to be tested but not scheduled.

The main interest of this command is to reduce delays that might occur on cryptographic operations as TPM must test the algorithm prior using it.

Alg_spec_list

A space-separated list of algorithm suite to be tested. Algorithms should follow the "formatting standards", see section "Algorithm Specifiers". Also, see section "Supported Hash Algorithms" for a list of supported hash algorithms.

If ALG_SPEC_LIST is left empty, tpm2_incrementalselftest(1) will return the list of algorithms left to be tested. Please note that in this case these algorithms are NOT scheduled to be tested.

If ALG_SPEC_LIST is not empty, tpm2_incrementalselftest(1) will return the list of algorithms that remains to be tested. This list contains algorithms scheduled for testing AND algorithms that remains to be tested and not yet scheduled. This can occur for instance if all AES mode have not been already tested yet.

Output

List of algorithms to be tested (implying scheduled) or remain to be tested (not scheduled) is also printed in YAML format.

If none of the specified algorithm is printed, that means both that they are already tested AND that these algorithms won't be tested again.

Options

This tool accepts no tool specific options.

References

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".

Asymmetric

  • rsa
  • ecc

Symmetric

  • aes
  • camellia

Hashing Algorithms

  • sha1
  • sha256
  • sha384
  • sha512
  • sm3_256
  • sha3_256
  • sha3_384
  • sha3_512

Keyed Hash

  • hmac
  • xor

Signing Schemes

  • rsassa
  • rsapss
  • ecdsa
  • ecdaa
  • ecschnorr

Asymmetric Encryption Schemes

  • oaep
  • rsaes
  • ecdh

Modes

  • ctr
  • ofb
  • cbc
  • cfb
  • ecb

Misc

  • null

Complex Specifiers

Objects, when specified for creation by the TPM, have numerous algorithms 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 remaining scheme and symmetric details will default based on the type specified and the type of the object being created.

  • aes - Default AES: aes128
  • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb). If mode is not specified, defaults to null.
  • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
  • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
  • ecc - Elliptical Curve, defaults to ecc256.
  • ecc192 - 192 bit ECC
  • ecc224 - 224 bit ECC
  • ecc256 - 256 bit ECC
  • ecc384 - 384 bit ECC
  • ecc521 - 521 bit ECC
  • rsa - Default RSA: rsa2048
  • rsa1024 - RSA with 1024 bit keysize.
  • rsa2048 - RSA with 2048 bit keysize.
  • 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 signing 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 algorithm, For example: oaep-sha256.

  • oaep
  • ecdh
  • rsassa
  • rsapss
  • ecdsa
  • 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 asymmetric objects symmetric details defaults to aes128cfb.

Examples

Create an rsa2048 key with an rsaes asymmetric encryption scheme

tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -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:ecdaa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.

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:

<tcti-name>:<tcti-option-config>

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:

Examples

Request testing of RSA algorithm

tpm2_incrementalselftest rsa

Request testing of multiple algorithms

tpm2_incrementalselftest rsa ecc xor aes cbc

Notes

Algorithm suite specified can imply either testing the combination or the complete suite, depending on TPM manufacturer implementation.

e.g : One TPM might only test AES with CTR mode if "aes ctr" is specified. An other might also test complete AES mode list AND test ctr mode.

If an algorithm has already been tested, this command won't permit re-executing the test. Only issuing tpm2_selftest(1) in full-test mode enabled will force re-testing.

Returns

Tools can return any of the following codes:

Bugs

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

Help

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

Info

tpm2-tools General Commands Manual