Platform SDK: WinTrust

WinVerifyTrust

The WinVerifyTrust function performs a trust verification action on a specified object. The function passes the inquiry to a trust provider, if one exists, that supports the action identifier.

HRESULT WINAPI WinVerifyTrust(
  HWND hWnd, 
  GUID *pgActionID, 
  WINTRUST_DATA *pWinTrustData 
);

Parameters

hWnd

[in] Optional handle to a caller window. A trust provider can use this value to determine whether it can interact with the user. However, trust providers typically perform verification actions with input from the user.

This parameter can be one of the following values:

Value Meaning

INVALID_HANDLE_VALUE There is no interactive user. The trust provider performs the verification action without the user's assistance.

Zero The trust provider can use the interactive desktop to display its user interface.

A valid window handle A trust provider can treat any value other than INVALID_HANDLE_VALUE or zero as a valid window handle that it can use to interact with the user.

pgActionID

Value	Meaning
INVALID_HANDLE_VALUE	There is no interactive user. The trust provider performs the verification action without the user's assistance.
Zero	The trust provider can use the interactive desktop to display its user interface.
A valid window handle	A trust provider can treat any value other than INVALID_HANDLE_VALUE or zero as a valid window handle that it can use to interact with the user.

[in] Pointer to a GUID structure that identifies an action and the trust provider that supports that action. This value indicates the type of verification action to be performed on the structure pointed to by pWinTrustData.

The WinTrust service is designed to work with trust providers implemented by third parties. Each trust provider provides its own unique set of action identifiers. For information about the action identifiers supported by a trust provider, see the documentation for that trust provider.

For example, Microsoft provides a Software Publisher Trust Provider that can establish the trustworthiness of software being downloaded from the Internet or some other public network. The Software Publisher Trust Provider supports the following action identifiers.

Value Description

WINTRUST_ACTION_GENERIC_VERIFY Verifiy a certificate chain only.

WINTRUST_ACTION_GENERIC_VERIFY_V2 Verify a file or object using the Microsoft Authenticode Policy Provider.

HTTPSPROV_ACTION Verify an SSL/PCT connection through Internet Explorer.

pWinTrustData

Value	Description
WINTRUST_ACTION_GENERIC_VERIFY	Verifiy a certificate chain only.
WINTRUST_ACTION_GENERIC_VERIFY_V2	Verify a file or object using the Microsoft Authenticode Policy Provider.
HTTPSPROV_ACTION	Verify an SSL/PCT connection through Internet Explorer.

[in] Pointer to a WINTRUST_DATA structure that contains information that the trust provider needs to process the specified action identifier. Typically, the structure includes information that identifies the object that the trust provider must evaluate.

The format of the structure depends on the action identifier. For information about the data required for a specific action identifier, see the documentation for the trust provider that supports that action.

Return Values

If the trust provider verifies that the subject is trusted for the specified action, the return value is ERROR_SUCCESS. Otherwise, the function returns a status code from the trust provider.

For example, a trust provider might indicate that the subject is not trusted, or is trusted but with limitations or warnings. The return value can be a trust-provider-specific value described in the documentation for an individual trust provider, or it can be one of the following error codes.

Value	Meaning
TRUST_E_SUBJECT_NOT_TRUSTED	The subject failed the specified verification action. Most trust providers return a more detailed error code that describes the reason for the failure.
TRUST_E_PROVIDER_UNKNOWN	The trust provider is not recognized on this system.
TRUST_E_ACTION_UNKNOWN	The trust provider does not support the specified action.
TRUST_E_SUBJECT_FORM_UNKNOWN	The trust provider does not support the form specified for the subject.

Remarks

The WinVerifyTrust function enables applications to invoke a trust provider to verify that a specified object satisfies the criteria of a specified verification operation. The pgActionID parameter identifies the verification operation, and the pWinTrustData parameter identifies the object whose trust is to be verified. A trust provider is a DLL registered with WinTrust. A call to WinVerifyTrust forwards that call to the registered trust provider, if there is one, that supports that specified action identifier.

For example, the Software Publisher Trust Provider can verify that an executable image file comes from a trusted software publisher and that the file has not been modified since it was published. In this case, the pWinTrustData parameter specifies the name of the file and the type of file, such as a Microsoft Portable Executable image file or a Java class file.

Each trust provider supports a specific set of actions that it can evaluate. Each action has a globally unique identifier (GUID) that identifies it. A trust provider can support any number of action identifiers, but two trust providers cannot support the same action identifier.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Windows 95/98: Unsupported.
  Header: Declared in winbase.h.
  Import Library: Use wintrust.lib.