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NCryptVerifySignature function (ncrypt.h)

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The NCryptVerifySignature function verifies that the specified signature matches the specified hash.

Syntax

SECURITY_STATUS NCryptVerifySignature(
  [in]           NCRYPT_KEY_HANDLE hKey,
  [in, optional] VOID              *pPaddingInfo,
  [in]           PBYTE             pbHashValue,
  [in]           DWORD             cbHashValue,
  [in]           PBYTE             pbSignature,
  [in]           DWORD             cbSignature,
  [in]           DWORD             dwFlags
);

Parameters

[in] hKey

The handle of the key to use to decrypt the signature. This must be an identical key or the public key portion of the key pair used to sign the data with the NCryptSignHash function.

[in, optional] pPaddingInfo

A pointer to a structure that contains padding information. The actual type of structure this parameter points to depends on the value of the dwFlags parameter. This parameter is only used with asymmetric keys and must be NULL otherwise.

[in] pbHashValue

The address of a buffer that contains the hash of the data. The cbHash parameter contains the size of this buffer.

[in] cbHashValue

The size, in bytes, of the pbHash buffer.

[in] pbSignature

The address of a buffer that contains the signed hash of the data. The NCryptSignHash function is used to create the signature. The cbSignature parameter contains the size of this buffer.

[in] cbSignature

The size, in bytes, of the pbSignature buffer. The NCryptSignHash function is used to create the signature.

[in] dwFlags

Flags that modify function behavior. The allowed set of flags depends on the type of key specified by the hKey parameter.

If the key is a symmetric key, this parameter is not used and should be zero.

If the key is an asymmetric key, this can be one of the following values.

Value Meaning
NCRYPT_PAD_PKCS1_FLAG
 The PKCS1 padding scheme was used when the signature was created. The pPaddingInfo parameter is a pointer to a BCRYPT_PKCS1_PADDING_INFO structure.
NCRYPT_PAD_PSS_FLAG
 The Probabilistic Signature Scheme (PSS) padding scheme was used when the signature was created. The pPaddingInfo parameter is a pointer to a BCRYPT_PSS_PADDING_INFO structure.
NCRYPT_SILENT_FLAG
 Requests that the key service provider (KSP) not display any user interface. If the provider must display the UI to operate, the call fails and the KSP should set the NTE_SILENT_CONTEXT error code as the last error.

Return value

Returns a status code that indicates the success or failure of the function.

Possible return codes include, but are not limited to, the following.

Return code Description
ERROR_SUCCESS
 The function was successful.
NTE_BAD_SIGNATURE
 The signature was not verified.
NTE_INVALID_HANDLE
 The hKey parameter is not valid.
NTE_NO_MEMORY
 A memory allocation failure occurred.
NTE_NOT_SUPPORTED
 The algorithm provider used to create the key handle specified by the hKey parameter is not a signing algorithm.

Remarks

A service must not call this function from its StartService Function. If a service calls this function from its StartService function, a deadlock can occur, and the service may stop responding.

Requirements

Requirement Value
Minimum supported client Windows Vista [desktop apps | UWP apps]
Minimum supported server Windows Server 2008 [desktop apps | UWP apps]
Target Platform Windows
Header ncrypt.h
Library Ncrypt.lib
DLL Ncrypt.dll

See also

NCryptSignHash