TPM recommendations

This article provides recommendations for Trusted Platform Module (TPM) technology for Windows.

For a basic feature description of TPM, see the Trusted Platform Module Technology Overview.

Traditionally, TPMs are discrete chips soldered to a computer's motherboard. Such implementations allow the computer's original equipment manufacturer (OEM) to evaluate and certify the TPM separate from the rest of the system. Discrete TPM implementations are common. However, they can be problematic for integrated devices that are small or have low power consumption. Some newer TPM implementations integrate TPM functionality into the same chipset as other platform components while still providing logical separation similar to discrete TPM chips.

TPMs are passive: they receive commands and return responses. To realize the full benefit of a TPM, the OEM must carefully integrate system hardware and firmware with the TPM to send it commands and react to its responses. TPMs were originally designed to provide security and privacy benefits to a platform's owner and users, but newer versions can provide security and privacy benefits to the system hardware itself. Before it can be used for advanced scenarios, however, a TPM must be provisioned. Windows automatically provisions a TPM, but if the user is planning to reinstall the operating system, they may need to clear the TPM before reinstalling so that Windows can take full advantage of the TPM.

The Trusted Computing Group (TCG) is the nonprofit organization that publishes and maintains the TPM specification. The TCG exists to develop, define, and promote vendor-neutral, global industry standards. These standards support a hardware-based root of trust for interoperable trusted computing platforms. The TCG also publishes the TPM specification as the international standard ISO/IEC 11889, using the Publicly Available Specification Submission Process that the Joint Technical Committee 1 defines between the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC).

OEMs implement the TPM as a component in a trusted computing platform, such as a PC, tablet, or phone. Trusted computing platforms use the TPM to support privacy and security scenarios that software alone can't achieve. For example, software alone can't reliably report whether malware is present during the system startup process. The close integration between TPM and platform increases the transparency of the startup process and supports evaluating device health by enabling reliable measuring and reporting of the software that starts the device. Implementation of a TPM as part of a trusted computing platform provides a hardware root of trust-that is, it behaves in a trusted way. For example, if a key stored in a TPM has properties that disallow exporting the key, that key truly can't leave the TPM.

The TCG designed the TPM as a low-cost, mass-market security solution that addresses the requirements of different customer segments. There are variations in the security properties of different TPM implementations just as there are variations in customer and regulatory requirements for different sectors. In public-sector procurement, for example, some governments clearly define security requirements for TPMs whereas others don't.

From an industry standard, Microsoft has been an industry leader in moving and standardizing on TPM 2.0, which has many key realized benefits across algorithms, crypto, hierarchy, root keys, authorization, and NV RAM.

TPM 2.0 products and systems have important security advantages over TPM 1.2, including:

• The TPM 1.2 spec only allows for the use of RSA and the SHA-1 hashing algorithm.
• For security reasons, some entities are moving away from SHA-1. Notably, NIST requires many federal agencies to move to SHA-256 as of 2014, and technology leaders, including Microsoft and Google have removed support for SHA-1 based signing or certificates in 2017.
• TPM 2.0 enables greater crypto agility by being more flexible with respect to cryptographic algorithms.
  • TPM 2.0 supports newer algorithms, which can improve drive signing and key generation performance. For the full list of supported algorithms, see the TCG Algorithm Registry. Some TPMs don't support all algorithms.
  • For the list of algorithms that Windows supports in the platform cryptographic storage provider, see CNG Cryptographic Algorithm Providers.
  • TPM 2.0 achieved ISO standardization (ISO/IEC 11889:2015).
  • Use of TPM 2.0 may help eliminate the need for OEMs to make exception to standard configurations for certain countries and regions.
• TPM 2.0 offers a more consistent experience across different implementations.
  • TPM 1.2 implementations vary in policy settings. This may result in support issues as lockout policies vary.
  • TPM 2.0 lockout policy is configured by Windows, ensuring a consistent dictionary attack protection guarantee.
• While TPM 1.2 parts are discrete silicon components, which are typically soldered on the motherboard, TPM 2.0 is available as a discrete (dTPM) silicon component in a single semiconductor package, an integrated component incorporated in one or more semiconductor packages - alongside other logic units in the same package(s), and as a firmware (fTPM) based component running in a trusted execution environment (TEE) on a general purpose SoC.

There are three implementation options for TPMs:

• Discrete TPM chip as a separate component in its own semiconductor package.
• Integrated TPM solution, using dedicated hardware integrated into one or more semiconductor packages alongside, but logically separate from, other components.
• Firmware TPM solution, running the TPM in firmware in a Trusted Execution mode of a general purpose computation unit.

Windows uses any compatible TPM in the same way. Microsoft doesn't take a position on which way a TPM should be implemented and there's a wide ecosystem of available TPM solutions, which should suit all needs.

For end consumers, TPM is behind the scenes but is still relevant. TPM is used for Windows Hello, Windows Hello for Business and in the future, will be a component of many other key security features in Windows. TPM secures the PIN, helps encrypt passwords, and builds on our overall Windows experience story for security as a critical pillar. Using Windows on a system with a TPM enables a deeper and broader level of security coverage.

• Since July 28, 2016, all new device models, lines, or series (or if you're updating the hardware configuration of an existing model, line, or series with a major update, such as CPU, graphic cards) must implement and enable by default TPM 2.0 (details in section 3.7 of the Minimum hardware requirements page). The requirement to enable TPM 2.0 only applies to the manufacturing of new devices. For TPM recommendations for specific Windows features, see TPM and Windows Features.

• TPM is optional on IoT Core.

• TPM is optional for Windows Server SKUs unless the SKU meets the other qualification (AQ) criteria for the Host Guardian Services scenario in which case TPM 2.0 is required.

The following table defines which Windows features require TPM support.

Government customers and enterprise customers in regulated industries may have acquisition standards that require use of common certified TPM parts. As a result, OEMs, who provide the devices, may be required to use only certified TPM components on their commercial class systems. For more information, contact your OEM or hardware vendor.