CryptMsgGetAndVerifySigner function

The CryptMsgGetAndVerifySigner function verifies a cryptographic message's signature.

Syntax

BOOL WINAPI CryptMsgGetAndVerifySigner(
  _In_        HCRYPTMSG      hCryptMsg,
  _In_        DWORD          cSignerStore,
  _In_opt_    HCERTSTORE     *rghSignerStore,
  _In_        DWORD          dwFlags,
  _Out_opt_   PCCERT_CONTEXT *ppSigner,
  _Inout_opt_ DWORD          *pdwSignerIndex
);

Parameters

hCryptMsg [in]

Handle of a cryptographic message.

cSignerStore [in]

Number of stores in the rghSignerStore array.

rghSignerStore [in, optional]

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

dwFlags [in]

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.

 

ppSigner [out, optional]

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.

pdwSignerIndex [in, out, optional]

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

See also

Verification Functions Using CTLs

CERT_CONTEXT

CTL_CONTEXT

CryptMsgOpenToDecode

CryptMsgControl