tpm2_createprimary(1)

📦
version 5.8 · 10 versions
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tpm2_createprimary(1) — Create a primary key 💅✨

NAME

okay so tpm2_createprimary(1) is literally the command for creating a primary key. iconic behavior, no cap 🫶

SYNOPSIS

tpm2_createprimary [OPTIONS]

DESCRIPTION

tpm2_createprimary(1) is used to create a primary object under one of the hierarchies: Owner, Platform, Endorsement, NULL. The command will create and load a Primary Object. The sensitive and public portions are not returned. A context file for the created object’s handle is saved as a file for future interactions with the created primary. slay, your primary is saved for later 💾✨

OPTIONS

  • -C, --hierarchy=OBJECT — The hierarchy under which the object is created. This will also dictate which authorization secret (if any) must be supplied. Defaults to TPM_RH_OWNER when no value is specified. Supported options are:
    • o for TPM_RH_OWNER
    • p for TPM_RH_PLATFORM
    • e for TPM_RH_ENDORSEMENT
    • n for TPM_RH_NULL
    • <num> where a raw number can be used.
  • -P, --hierarchy-auth=AUTH — The authorization value for the hierarchy specified with -C. 🔐
  • -p, --key-auth=AUTH — The authorization value for the primary object created. 🎀
  • -g, --hash-algorithm=ALGORITHM — The hash algorithm to use for generating the objects name. Defaults to sha256 if not specified. ✨
  • -G, --key-algorithm=ALGORITHM — The algorithm type for the generated primary key. Defaults to rsa2048:null:aes128cfb. 👑
  • -c, --key-context=FILE — The file path to save the object context of the generated primary object. 🗂️
  • -L, --policy=FILE or HEX_STRING — An optional file input or hex string that contains the policy digest for policy based authorization of the object. 🧚
  • -a, --attributes=ATTRIBUTES — The object attributes, optional. Defaults to:
TPMA_OBJECT_RESTRICTED|TPMA_OBJECT_DECRYPT|TPMA_OBJECT_FIXEDTPM|
TPMA_OBJECT_FIXEDPARENT|TPMA_OBJECT_SENSITIVEDATAORIGIN|
TPMA_OBJECT_USERWITHAUTH
  • -u, --unique-data=FILE OR STDIN — An optional file input that contains the unique field of TPMT_PUBLIC in little-endian format. Primary key creator may place information that causes the primary key generation scheme internal to the TPM to generate statistically unique values. The TPM v2.0 specification calls this field unique and overloads it so that it contains one value when the application provides this structure as input and another value when the applications receives this structure as output (like public portion of the rsa key). 😭

If the data is specified as a file, the user is responsible for ensuring that this buffer is formatted per TPMU_PUBLIC_ID union. 🫶

The unique data can also be retrieved from stdin buffer by specifying - as the --unique-data option value and the tool will parse the key type and associate the input data with the unique data buffer associated with the key type. 💀

NOTE:

  1. The maximum allowed bytes is dependent on key type and the TPM implementation. Eg. While TSS allows a value upto 512 for MAX_RSA_KEY_BYTES, however the ibmSwTPM implementation supports a value upto 256 bytes.
  2. The unique input data specified on stdin for ECC is split for specifying the X coordinate and Y coordinate buffers.
  • --creation-data=FILE — An optional file output that saves the creation data for certification. 🌸
  • --template-data=FILE — An optional file output that saves the key template data (TPM2B_PUBLIC) to be used in tpm2_policytemplate. 🎀
  • -t, --creation-ticket=FILE — An optional file output that saves the creation ticket for certification. 🎟️
  • -d, --creation-hash=FILE — An optional file output that saves the creation hash for certification. 🧾
  • -q, --outside-info=FILE_OR_HEX — An optional file or hex string to add unique data to the creation data. Note that it does not contribute in creating statistically unique object. 🦋
  • -l, --pcr-list=PCR — The list of PCR banks and selected PCRs’ ids for each bank to be included in the creation data for certification. 🌈
  • --cphash=FILE — File path to record the hash of the command parameters. This is commonly termed as cpHash. NOTE: When this option is selected, The tool will not actually execute the command, it simply returns a cpHash. ⚠️
  • -f, --format — Format selection for the public key output file. tss (the default) will output a binary blob according to the TPM 2.0 Specification. pem will output an OpenSSL compatible PEM encoded public key. der will output an OpenSSL compatible DER encoded public key. tpmt will output a binary blob of the TPMT_PUBLIC struct referenced by TPM 2.0 specs.

Public key format. 🔑

  • -o, --output=FILE — The output file path, recording the public portion of the object. 💖

References 🫶

Context Object Format 🧭

The type of a context object, whether it is a handle or file name, is determined according to the following logic in-order:

  • If the argument is a file path, then the file is loaded as a restored TPM transient object.
  • If the argument is a prefix match on one of:
    • owner: the owner hierarchy
    • platform: the platform hierarchy
    • endorsement: the endorsement hierarchy
    • lockout: the lockout control persistent object
  • If the argument can be loaded as a number it will be treated as a handle, e.g. 0x81010013, and used directly. _OBJECT_

Authorization Formatting 🔐

Authorization for use of an object in TPM2.0 can come in 3 different forms:

  1. Password
  2. HMAC
  3. Sessions
NOTE: “Authorizations default to the EMPTY PASSWORD when not specified”.

For authentication with auth values, the tool commands implicitly generate an HMAC session. Thus passwords are not transmitted unencrypted. This does not apply to passwords defined for objects. In this case, an HMAC session should be used (see tpm2_startauthsession(1)). 😌

Passwords 🔑

Passwords are interpreted in the following forms below using prefix identifiers.

Note: By default passwords are assumed to be in the string form when they do not have a prefix.

String

A string password, specified by prefix str: or it’s absence (raw string without prefix) is not interpreted, and is directly used for authorization.

Examples

foobar
str:foobar

Hex-string

A hex-string password, specified by prefix hex: is converted from a hexidecimal form into a byte array form, thus allowing passwords with non-printable and/or terminal un-friendly characters.

Example

hex:1122334455667788

File

A file based password, specified be prefix file: should be the path of a file containing the password to be read by the tool or a - to use stdin. Storing passwords in files prevents information leakage, passwords passed as options can be read from the process list or common shell history features. 🙈

Examples

# to use stdin and be prompted
file:-

# to use a file from a path
file:path/to/password/file

# to echo a password via stdin:
echo foobar | tpm2_tool -p file:-

# to use a bash here-string via stdin:

tpm2_tool -p file:- <<< foobar

Sessions 🎟️

When using a policy session to authorize the use of an object, prefix the option argument with the session keyword. Then indicate a path to a session file that was created with tpm2_startauthsession(1). Optionally, if the session requires an auth value to be sent with the session handle (eg policy password), then append a + and a string as described in the Passwords section.

Examples

To use a session context file called session.ctx.

session:session.ctx

To use a session context file called session.ctx AND send the authvalue mypassword.

session:session.ctx+mypassword

To use a session context file called session.ctx AND send the HEX authvalue 0x11223344.

session:session.ctx+hex:11223344

PCR Authorizations 🌸

You can satisfy a PCR policy using the pcr: prefix and the PCR minilanguage. The PCR minilanguage is as follows:

<pcr-spec>=<raw-pcr-file>

The PCR spec is documented in the section “PCR bank specifiers”.

The raw-pcr-file is an optional argument that contains the output of the raw PCR contents as returned by tpm2_pcrread(1).

PCR bank specifiers

Examples

To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifier of:

pcr:sha256:0,1,2,3

specifying AUTH. ✨

🌈 Algorithm Specifiers 🌈

So every option that takes an algorithm? It's gonna accept something we call “nice-names”. Very demure, very readable. 💅

There are two big classes of these algorithm specifier strings — simple and complex. But heads up bestie: only certain algorithms get accepted by the TPM, depending on what you're doing and under what conditions. It's giving ✨situationship✨ with the spec.

Simple specifiers

These are strings with literally no extra data tacked on. When you're creating objects, any part of the object you didn't specify just gets assumed to be the defaults. The full list of known “Simple Specifiers” is right below, babe. 🫶

Asymmetric

  • rsa
  • ecc

Symmetric

  • aes
  • camellia
  • sm4

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
  • sm2

Asymmetric Encryption Schemes

  • oaep
  • rsaes
  • ecdh

Modes

  • ctr
  • ofb
  • cbc
  • cfb
  • ecb

Misc

  • null

Complex Specifiers

Okay so when objects get specified for creation by the TPM, they've got a ton of algorithms to populate in the public data. Type, scheme, asymmetric details, key size — the whole ensemble, it's giving main character energy. 🌟 Here's the general format for specifying all that:

<type>:<scheme>:<symmetric-details>

Type Specifiers

This part of the complex algorithm specifier is required, no skipping it. The remaining scheme and symmetric details? They default based on the type you picked and the type of object being created.

  • aes — Default AES: aes128
  • aes128<mode> — 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb). If mode isn't specified, it 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.
  • sm4 — Default SM4: sm4128
  • sm4128 or sm4_128 <mode> — 128 bit SM4 with optional mode (ctr|ofb|cbc|cfb|ecb). If mode isn't specified, it defaults to null.
  • ecc — Elliptical Curve, defaults to ecc256.
  • ecc192 or ecc_nist_p192 — 192 bit ECC NIST curve
  • ecc224 or ecc_nist_p224 — 224 bit ECC NIST curve
  • ecc256 or ecc_nist_p256 — 256 bit ECC NIST curve
  • ecc384 or ecc_nist_p384 — 384 bit ECC NIST curve
  • ecc521 or ecc_nist_p521 — 521 bit ECC NIST curve
  • ecc_sm2 or ecc_sm2_p256 — 256 bit SM2 curve
  • rsa — Default RSA: rsa2048
  • rsa1024 — RSA with 1024 bit keysize.
  • rsa2048 — RSA with 2048 bit keysize.
  • rsa3072 — RSA with 3072 bit keysize.
  • rsa4096 — RSA with 4096 bit keysize.

Scheme Specifiers

Next up is an optional field — you can absolutely skip it if you want. ✨

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 at all, and some get greedy and take multiple arguments. 🙈

Hash Optional Scheme Specifiers

These scheme specifiers get followed by a dash and a valid hash algorithm. For example: oaep-sha256.

  • oaep
  • ecdh
  • rsassa
  • rsapss
  • ecdsa
  • ecschnorr
  • sm2

Multiple Option Scheme Specifiers

This scheme specifier gets followed by a count (max size UINT16), then a dash (-), then a valid hash algorithm. So like, ecdaa. Example: ecdaa4-sha256. If you don't specify a count, it defaults to 4.

No Option Scheme Specifiers

This scheme specifier takes NO arguments. Periodt.

  • rsaes

Symmetric Details Specifiers

This field is optional too, and it defaults based on the type of object being created and its attributes. Generally, any valid Symmetric specifier from the Type Specifiers list up there should work. And if you don't specify it, an asymmetric object's symmetric details default 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.

🦋 Object Attributes 🦋

Object Attributes are what you use to control all the various properties of created objects. When you specify one as an option, you can use either the raw bitfield mask or the “nice-names”. The values live in Table 31 Part 2 of the TPM2.0 specification, which you can find right here:

https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-2-Structures-01.38.pdf

Nice names are calculated by taking the name field of table 31, removing the prefix TPMA_OBJECT_, and lowercasing the result. So TPMA_OBJECT_FIXEDTPM becomes fixedtpm. Slay, honestly. 💅 Nice names can be joined together using the bitwise or | symbol.

For instance, to set the fields TPMA_OBJECT_FIXEDTPM, TPMA_OBJECT_NODA, and TPMA_OBJECT_SIGN_ENCRYPT, the argument would be:

fixedtpm|noda|sign

…specifying the object attributes ATTRIBUTES.

🎀 COMMON OPTIONS 🎀

This collection of options is common to many programs and hands over info that lots of users probably expect to find. The classics, basically. 👑

  • -h, --help=[man|no-man] — Display the tool's manpage. By default it tries to invoke the manpager for the tool, but if that fails it'll output a short tool summary instead. Same behavior if you pass the man option argument — but if you explicitly ask for man, the tool will give you the errors from man on stderr. And if you pass no-man, or if the manpager fails, the short options get output to stdout.

To successfully use the manpages feature you need the manpages installed or on MANPATH. See man(1) for more details.

  • -v, --version — Display version information for this tool, the supported tctis, and exit. 🌸
  • -V, --verbose — Increase the information the tool prints to the console while it's running. When you use this option, the file and line number get printed too. iykyk 🔍
  • -Q, --quiet — Silence normal tool output to stdout. Shhh. 🤫
  • -Z, --enable-errata — Enable the application of errata fixups. Useful if an errata fixup needs to be applied to commands sent to the TPM. Defining the environment variable TPM2TOOLS_ENABLE_ERRATA is equivalent.
  • -z, --pwd-session — Use a password session instead of a HMAC session for authentication. A clear text password is passed to the TPM to authorize the action. This option can be used to avoid problems when unsalted sessions are used in OpenSSL FIPS mode. If auth values are used, a salted session should be used for authentication. ⚠️
  • -R, --autoflush — Enable autoflush for transient objects created by the command. If a parent object is loaded from a context file, the transient parent object gets flushed too. Autoflush can also be activated if the environment variable TPM2TOOLS_AUTOFLUSH is set to yes or true.
Everything above is information many users may expect. 💖

💜 TCTI Configuration 💜

The TCTI, aka the “Transmission Interface”, is the communication mechanism with the TPM. TCTIs can be swapped out so you can talk to TPMs across different mediums. Very versatile, we love her. 🦋

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. No cap.

The current known TCTIs are:

  • tabrmd — The resource manager, called tabrmd. Note that tabrmd and abrmd as a tcti name are synonymous. 👯
  • mssim — Typically used for communicating to the TPM software simulator.
  • device — Used when talking directly to a TPM device file.
  • none — Do not initalize a connection with the TPM. Some tools allow for off-tpm options and thus support not using a TCTI. Tools that don't support it will error when you try to use them without a TCTI connection. Does not support ANY options and MUST BE presented as the exact text of none. ⚠️

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

TCTI Defaults

When a TCTI isn't specified, the default TCTI gets 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 which TCTI will be chosen as the default by using the -v option to print the version information. The default-tcti key-value pair will tell you 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. So this could be a path to the shared library, or a library name as understood by dlopen(3) semantics. Go wild. 🌈

⭐ TCTI OPTIONS ⭐

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

  • device — For the device TCTI, the TPM character device file for use by the device TCTI can be specified. The default is /dev/tpm0.

Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="device:/dev/tpm0"

  • mssim — For the mssim TCTI, the domain name or IP address and port number used by the simulator can be specified. The defaults are 127.0.0.1 and 2321.

Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TCTI="mssim:host=localhost,port=2321"

  • abrmd — For the abrmd TCTI, the configuration string format is a series of simple key value pairs separated by a , character. Each key and value string are separated by a = character.
    • TCTI abrmd supports two keys:
      1. bus_name : The name of the tabrmd service on the bus (a string).
      2. bus_type : The type of the dbus instance (a string) limited to session and system.

Specify the tabrmd tcti name and a config string of bus_name=com.example.FooBar:

--tcti=tabrmd:bus_name=com.example.FooBar

Specify the default (abrmd) tcti and a config string of bus_type=session:

--tcti:bus_type=session
NOTE: abrmd and tabrmd are synonymous. 💀

…the various known TCTI modules. 🫶

✨ EXAMPLES ✨

🌸 Create an ECC primary object

okay bestie, easiest lil starter recipe — ECC key, sha256, done:

tpm2_createprimary -C o -g sha256 -G ecc -c context.out

🎀 Create a primary object that follows the guidance of TCG Provisioning guide

See : https://trustedcomputinggroup.org/wp-content/uploads/TCG-TPM-v2.0-Provisioning-Guidance-Published-v1r1.pdf

Where unique.dat contains the binary-formatted data: 0x00 0x01 (0x00 * 256)

tpm2_createprimary -C o -G rsa2048:aes128cfb -g sha256 -c prim.ctx \
-a 'restricted|decrypt|fixedtpm|fixedparent|sensitivedataorigin|userwithauth|\
noda' -u unique.dat

like… yes the attribute string is giving "essay due at 11:59pm" energy 😭 but it's iconique and it works, trust 💅

## Create a primary object and output the public key in pem format
tpm2_createprimary -c primary.ctx --format=pem --output=public.pem

pem output?? we love a portable moment 🦋

🌈 Returns

Tools can return any of the following codes:

  • 0 - Success. (the slay outcome ✨)
  • 1 - General non-specific error.
  • 2 - Options handling error.
  • 3 - Authentication error.
  • 4 - TCTI related error.
  • 5 - Non supported scheme. Applicable to tpm2_testparams.
ngl, 0 is the only one we're manifesting 🫶 the rest are… not the vibe.

💀 BUGS

Github Issues

(yeah, that's the whole thing. go file one, bestie, they're literally waiting 🙈)

🧚 HELP

See the Mailing List

👑 License

This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).

okay that's the whole page, you're officially a primary-object-creating legend now ⭐ that was tpm2-tools, tpm2_createprimary(1), and it's dated and versioned by the toolchain itself — mwah, go touch some grass and then go make some keys 💖🌸🎀

📦 where this page comes from