cbSize

Size of this structure in bytes.

hCryptProv

Specifies a handle to the cryptographic service provider (CSP) used to do content encryption, recipient key encryption, and export. The hCryptProv's private keys are not used.

Unless there is a strong reason for passing in a specific cryptographic provider in hCryptProv, pass zero to use the default RSA or DSS provider.

ContentEncryptionAlgorithm

CRYPT_ALGORITHM_IDENTIFIERstructure contains the signature algorithm type and any associated additional parameters in encoded form.

The pszObjIdmember of the structure specifies the algorithm used to encrypt the message contents.

The following encryption algorithms require an encoded eight byte initialization vector (IV) in the Parametersmember of structure. For details, see CryptSetKeyParam.

Value	Description
CALG_DES	szOID_OIWSEC_desCBC
CALG_3DES	szOID_RSA_DES_EDE3_CBC

If the cbDatamember of the Parametersmember is zero, an ASN.1 encoded OCTET STRING containing the IV is generated using CryptGenRandom.

The szOID_RSA_RC2CBC (CALG_RC2) algorithm requires the pbData member of Parameters to be an encoded CRYPT_RC2_CBC_PARAMETERS structure. If the cbDatamember of the Parametersmember is zero, an ASN.1 encoded CRYPT_RC2_CBC_PARAMETERS is generated with a default value of 40 for the dwVersionmember. This sets the default key length to 40 bits. This default key length can be overridden with pvEncryptionAuxInfopointing to a CMSG_RC2_AUX_INFO structure containing the desired key length.

Note:
On decryption, if an IV exists, CryptSetKeyParamis called with the IV before decryption begins.

pvEncryptionAuxInfo

Pointer to a structure depending on the encryption algorithm.

Value	Description
RC2	CMSG_RC2_AUX_INFO
RC4	CMSG_RC4_AUX_INFO
SP3 or compatible	CMSG_SP3_COMPATIBLE_AUX_INFO
All other encryption algorithms	NULL

cRecipients

Number of elements in the rgpRecipientsor rgCmsRecipientsarray.

rgpRecipients

Pointer to an array of CERT_INFOstructures, each containing a recipient's certificate Issuer, SerialNumber, and SubjectPublicKeyInfo. This array can only be used for recipients identified by their Issuer and serial number. If rgpRecipientsis not NULL, rgCmsRecipientsmust be NULL.

rgCmsRecipients

This member can optionally be defined with Windows 2000 and later. Pointer to an array of CMSG_RECIPIENT_ENCODE_INFO structures, each containing recipient information. If rgCmsRecipientsis not NULL, rgpRecipientsmust be NULL. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

cCertEncoded

This member can optionally be defined with Windows 2000 and later. DWORDindicating the number of encoded certificates in the rgCertEncodedarray. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

rgCertEncoded

This member can optionally be defined with Windows 2000 and later. Pointer to an array of CERT_BLOBstructures. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

cCrlEncoded

This member can optionally be defined with Windows 2000 and later. DWORDindicating the number of encoded CRLs in the rgCRLEncodedarray. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

rgCrlEncoded

This member can optionally be defined with Windows 2000 and later. Pointer to an array of CRL_BLOBstructures. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

cAttrCertEncoded

This member can optionally be defined with Windows 2000 and later. DWORDindicating the number of encoded certificate attributes in the rgAttrCertEncodedarray. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

rgAttrCertEncoded

This member can optionally be defined with Windows 2000 or later. Pointer to an array of CRYPT_ATTRIBUTEstructures. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this member.

cUnprotectedAttr

This member can optionally be defined with Windows 2000 and later. DWORDindicating the number of unprotected attributes in the rgUnprotectedAttrarray. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

rgUnprotectedAttr

This member can optionally be defined with Windows 2000 and later. Pointer to an array of CRYPT_ATTRIBUTEstructures. CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference this field.

CMSG_ENVELOPED_ENCODE_INFO_HAS_CMS_FIELDS must be defined to reference the following structure members:

rgCmsRecipients

cCertEncoded

rgCertEncoded

cCrlEncoded

rgCrlEncoded

cAttrCertEncoded

rgAttrCertEncoded

cUnprotectedAttr

rgUnprotectedAttr