Allrite the payment collected on eBay India is by PaisaPay who I beleive use the industry standard encryption levels.
Some minimum features are required from the browser. But if there is any bug / loop hole in your browser then that requires a fix from the browser co. Use the latest version of FirFox or IE to be 100% secure.
Personally seeing how data is handled at other places J, I can tell you that PaisaPay appears to be the best option online in India.
Regards
TechiE
TechiE