windows-itpro-docs/windows/security/threat-protection/security-policy-settings/system-cryptography-force-strong-key-protection-for-user-keys-stored-on-the-computer.md

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System cryptography Force strong key protection for user keys stored on the computer (Windows 10)	Describes the best practices, location, values, policy management and security considerations for the System cryptography Force strong key protection for user keys stored on the computer security policy setting.	8cbff267-881e-4bf6-920d-b583a5ff7de0		dansimp	w10	deploy	library	security	medium	dansimp	dansimp	ITPro	M365-security-compliance	conceptual	04/19/2017

System cryptography: Force strong key protection for user keys stored on the computer

Applies to

• Windows 10

Describes the best practices, location, values, policy management and security considerations for the System cryptography: Force strong key protection for user keys stored on the computer security policy setting.

Reference

This policy setting determines whether users can use private keys, such as their Secure/Multipurpose Internet Mail Extensions (S/MIME) key, without a password.

Configuring this policy setting so that users must provide a password every time they use a key (in addition to their domain password) makes it more difficult for a malicious user to access locally-stored user keys, even if the attacker takes control of the user's device and determines their logon password.

Possible values

• User input is not required when new keys are stored and used
• User is prompted when the key is first used
• User must enter a password each time they use a key
• Not defined

Best practices

• Set this policy to User must enter a password each time they use a key. Users must enter their password every time they access a key that is stored on their computer. For example, if users use an S/MIME certificate to digitally sign their email, they will be forced to enter the password for that certificate every time they send a signed email message. For some organizations, the overhead that is caused by using this value might be too high, but they should set the value at a minimum to User is prompted when the key is first used.

Location

Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options

Default values

The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.

Server type or GPO	Default value
Default Domain Policy	Not defined
Default Domain Controller Policy	Not defined
Stand-Alone Server Default Settings	Not defined
DC Effective Default Settings	Not defined
Member Server Effective Default Settings	Not defined
Client Computer Effective Default Settings	Not defined

Policy management

This section describes features and tools that are available to help you manage this policy.

Restart requirement

None. Changes to this policy become effective without a device restart when they are saved locally or distributed through Group Policy.

Security considerations

This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.

Vulnerability

If a user's account is compromised or the user's device is inadvertently left unsecured, the malicious user can use the keys that are stored for the user to access protected resources.

Countermeasure

Configure the System cryptography: Force strong key protection for user keys stored on the computer setting to User must enter a password each time they use a key so that users must provide a password that is distinct from their domain password every time they use a key. This configuration makes it more difficult for an attacker to access locally stored user keys, even if the attacker takes control of the user's computer and determines the logon password.

Potential impact

Users must type their password every time they access a key that is stored on their device. For example, if users use an S/MIME certificate to digitally sign their email, they are forced to type the password for that certificate every time they send a signed email message. For some organizations, the overhead that is involved by using this configuration may be too high. At a minimum, this setting should be set to User is prompted when the key is first used.

Related topics

• Security Options