Online shopping is growing in popularity, but this should not be taken to mean that consumers are comfortable about the security aspects of spending money on the internet. On the contrary, the number of online shoppers who are concerned about purchasing online has increased over the past year.According to the latest HP-RFi Australian Payment Research Report, in March, 38 per cent of consumers said they were concerned about online security - up from 34 per cent last September.When asked how they rated their level of concern about providing personal information with online purchases, compared with three years ago, 24 per cent said they were somewhat more concerned and 18 per cent said they were much more concerned.Eighty-one per cent of Australian consumers say they shop online and a large number are making those purchases from a mobile phone. The proportion who made an online purchase from a mobile phone rose from 17 per cent last September to 21 per cent in March.The combination of increased online spending and heightened concern about security has led to a sharp increase in the use of PayPal, which is widely recognised as a secure online payment method. Since September 2011, the number of consumers using PayPal each month has increased from 29 per cent to 38 per cent. No other payment method has had such strong growth over the same period.