hSystemStore := CertOpenSystemStore(0, 'MY');
var
 hProv: HCRYPTPROV;
 hSystemStore: HCERTSTORE;
 myCert, test: PWideChar;
 SERT_NAME: LPCTSTR;
 pCert: PCCERT_CONTEXT;
 msgPara: CRYPT_ENCRYPT_MESSAGE_PARA;
 count, encType: DWORD;
begin
   encType := PKCS_7_ASN_ENCODING or X509_ASN_ENCODING;
     myCert := 'Makushev';
     pCert := CertFindCertificateInStore(hSystemStore,
       encType,
       0,
       CERT_FIND_SUBJECT_STR,
       myCert,
       nil);

   ZeroMemory(@msgPara, SizeOf(msgPara));
   with msgPara do
       begin
           cbSize := SizeOf(msgPara);
           dwMsgEncodingType := encType;
           ContentEncryptionAlgorithm.pszObjId := CertAlgIdToOID(CALG_RC4);
           hCryptProv := hProv;
       end;

       test := 'Test';
       ret := CryptEncryptMessage(@msgPara, 1, pCert, PByte(test), length(test), nil, @count);