I've got a firebird database in format .GDB.

Basically setup a interbase server and that i open the .GDB with (for ex. IB Expert) using the default password I'm able to open the Database.

So Let me avoid the database to become opened up by other softwares how could I actually do it?

with "gsec.exe" I'm able to add and modify customers, but this does not produce something to avoid a database to become opened up with a new firebird instance.

So far as I understand you can't avoid b .GDB or .FDB database to become opened up with a Interbase or Firebird instance. It's a file (or number of files) having a known structure for this kind of instance and, provided the (malicious) user knows the SYSDBA password, it may be utilized.

Stated this, a few recommendations:

  • If you don't require it make certain the Embedded version of Firebird isn't contained in your installation to prevent giving the consumer something that the database might be utilized directly.
  • So far as possible restrict any accessibility directory in which the database is going to be. Fire walls, directory user privileges, etc.
  • Use gsec.exe while you stated to includeOralter customers access privileges. Although this won't avoid the SYSDBA to gain access to the database a minimum of it'll prevent an ordinary user to do this.
  • Secure the filesystem in which the database is going to be. You'll find more information about this at How to protect data in Firebird database.
  • When the database will be utilized through insecure systems like Internet you could look at using SSL. Check How to protect the connection over insecure networks.
  • Check Firebird Security FAQ to learn more.

There's another solution that can help you partly: encrypting before storing data and decrypting when reading through data, but it may cause some problems on searching with the data, since you won't have the ability to apply certain indexes (really only PK and FK indexes works perfectly).

I understand this isn't the solution that you simply expected, so sorry about this. Maybe another person will include an alternate and solution. :-)