procedure TForm1.Button1Click(Sender: TObject);
var
  hProv: HCRYPTPROV;
  pbData: PBYTE;
  cbData, Flag: Cardinal;
begin
  if CryptAcquireContext(hProv, nil, CP_GR3410_2001_PROV_A, PROV_GOST_2001_DH, CRYPT_VERIFYCONTEXT) then
  begin
    Flag := CRYPT_FIRST;
    if CryptGetProvParam(hProv, PP_ENUMCONTAINERS, nil, cbData, Flag) then
    begin
      GetMem(pbData, 1024);
      try
        while CryptGetProvParam(hProv, PP_ENUMCONTAINERS, pbData, cbData, Flag) do
        begin
          Flag := CRYPT_NEXT;
          ShowMessage(PChar(pbData));
        end;
      finally
        FreeMem(pbData, 1024);
      end;
    end;
  end;
end;