CryptMsgCountersign function

The CryptMsgCountersign function countersigns an existing signature in a message. Countersignatures are used to sign an existing signature's encrypted hash of the message. Countersignatures can be used for various purposes including time stamping a message.

Syntax

BOOL WINAPI CryptMsgCountersign(
  _Inout_ HCRYPTMSG                hCryptMsg,
  _In_    DWORD                    dwIndex,
  _In_    DWORD                    cCountersigners,
  _In_    PCMSG_SIGNER_ENCODE_INFO rgCountersigners
);

Parameters

hCryptMsg [in, out]

Cryptographic message handle to be used.

dwIndex [in]

Zero-based index of the signer in the signed or signed-and-enveloped message to be countersigned.

cCountersigners [in]

Number of countersigners in the rgCountersigners array.

rgCountersigners [in]

Array of countersigners' CMSG_SIGNER_ENCODE_INFO structures.

Return value

If the function succeeds, the function returns nonzero (TRUE).

If the function fails, it returns zero (FALSE). For extended error information, call GetLastError.

An error can be propagated from CryptMsgCountersignEncoded.

The following error codes are returned most often.

If the function fails, GetLastError may return an Abstract Syntax Notation One (ASN.1) encoding/decoding error. For information about these errors, see ASN.1 Encoding/Decoding Return Values.

Examples

For an example that uses this function, see Example C Program: Encoding and Decoding a Countersigned Message.

Requirements

See also

Low-level Message Functions

Simplified Message Functions

CryptMsgCountersignEncoded

CryptMsgVerifyCountersignatureEncoded