The best strategy is to tell the truth about your current salary, but frame it well. If you inflate the number and they verify it with your current employer (and they often do), you're done for. Instead, you can be smart about how you communicate it: if you earn 28k gross, you can say "I currently make 28k, but I see this position as a step forward from where I am now, so I'm looking for an offer that matches the responsibilities you'll be giving me." That way you're not lying, but you're not shooting yourself in the foot by starting from a low base.
What changes is how you negotiate after. If you really think you're worth more (and maybe the new role is actually more senior), this isn't the time to bluff about past salaries - this is the time to talk about the value you bring to the new position. Ask yourself: what can I do that they're looking for? How much do I solve their problem? That's where you make your money, not by deceiving them about your previous history.
One thing that helped me is shifting the conversation: when they ask the direct question, I answer with the number, but I immediately ask what salary range they have in mind for the position. Often you find out their budget is already set regardless of what you made before, so you can relax. If the range is low, at least you know right away and can decide whether it's worth continuing or not.