Hey Anshul, that's a fair concern. And yes, just having an SSL connection doesn't make everything secure. We do take security seriously though - your cookies are encrypted and secure, and everything on IB is SQL-injection safe. We have other safeguards as well, which I naturally cannot outline. I'm not saying that we're 100% safe - nobody can say that without being arrogant. However, we will make sure that your information is as safe as possible.
As to the question on why we asked for it - as CyberKid mentioned, it is to do with wire transfers, and as far as possible, we need to use them. Sending out cheques simply adds too much overhead for everyone - online transfers are faster and have better accountability. Our experience with couriers in India have been quite sad so far, and we believe in eliminating middle men wherever possible. Rest assured, we will never, ever give out your personal information to anyone. Perhaps when we have more bandwidth, we can add more payment options!