CryptMsgGetAndVerifySigner function (wincrypt.h)

The CryptMsgGetAndVerifySigner function verifies a cryptographic message's signature.

Syntax

BOOL CryptMsgGetAndVerifySigner(
  [in]                HCRYPTMSG      hCryptMsg,
  [in]                DWORD          cSignerStore,
  [in, optional]      HCERTSTORE     *rghSignerStore,
  [in]                DWORD          dwFlags,
  [out, optional]     PCCERT_CONTEXT *ppSigner,
  [in, out, optional] DWORD          *pdwSignerIndex
);

Parameters

[in] hCryptMsg

Handle of a cryptographic message.

[in] cSignerStore

Number of stores in the rghSignerStore array.

[in, optional] rghSignerStore

Array of certificate store handles that can be searched for a signer's certificate.

[in] dwFlags

Indicates particular use of the function.

Value	Meaning
CMSG_TRUSTED_SIGNER_FLAG	The stores in rghSignerStore are assumed trusted and they are the only stores searched to find the certificate corresponding to the signer's issuer and serial number. Otherwise, signer stores can be provided to supplement the message's store of certificates. If a signer certificate is found, its public key is used to verify the message signature.
CMSG_SIGNER_ONLY_FLAG	Return the signer without doing the signature verification.
CMSG_USE_SIGNER_INDEX_FLAG	Only the signer specified by *pdwSignerIndex is returned. Otherwise, iterate through all the signers until a signature is verified or there are no more signers.

[out, optional] ppSigner

If the signature is verified, ppSigner is updated to point to the signer's certificate context. When you have finished using the certificate, free the context by calling the CertFreeCertificateContext function. This parameter can be NULL if the application has no need for the signer's certificate.

[in, out, optional] pdwSignerIndex

If the signature is verified, pdwSigner is updated to point to the index of the signer in the array of signers. This parameter can be NULL if the application has no need for the index of the signer.

Return value

If the function succeeds, the return value is nonzero (TRUE).

If the function fails, the return value is zero (FALSE). For extended error information, call GetLastError.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps | UWP apps]
Minimum supported server	Windows Server 2003 [desktop apps | UWP apps]
Target Platform	Windows
Header	wincrypt.h
Library	Crypt32.lib
DLL	Crypt32.dll

See also

CERT_CONTEXT

CTL_CONTEXT

CryptMsgControl

CryptMsgOpenToDecode

Verification Functions Using CTLs