Data you send over the phone typically is encrypted using methods similar to those for online bill pay, according to Niles Howard of Bankrate.com via MSN Money. From this standpoint, using your phone and debit card to pay a bill generally isn't any riskier than paying with your computer. However, not all data is encrypted. Text is the primary example, according to Liz Weston, also of MSN Money. If you want to pay a bill using your debit card, never text data like your account number or password -- opt for touch-tone systems instead.
Banks usually understand the importance of security and encrypting data sent through mobile devices. However, not all banks have the same level of security. This sometimes is due to budget issues -- it costs money to update encryption methods and applications. It also is due to the fact that technology constantly evolves. Banks have a hard time keeping up with all the applications people can use to pay bills with their debit cards, even when budgets are stable. How safe using your phone to pay a bill is, therefore, depends on which institution you use for banking.
Debit Versus Credit Cards
In general, credit cards offer better security against fraud and identity theft than debit cards do. For this reason, if you're going to pay a bill via phone, using your debit card probably shouldn't be the first choice unless you don't have a credit card. Some banks do offer considerable protection to customers; some will even pay 100 percent of losses or extend zero liability. In these cases, the only real reasons to use your credit card over your debit card are if you don't have enough money in your bank account to cover your bill, or if you want to work on your credit payment history and score.
The Final Call
Paying bills by phone and debit card can be just as safe as paying via other methods. However, you should check what security measures your bank takes for phone payments before you use them. Weston recommends using applications that can wipe sensitive data from your phone remotely if the phone is lost as well as password-protecting the mobile device you use and setting up text alerts with your bank for suspicious transactions. She also recommends installing software applications that can protect your phone from viruses and hackers. Lastly, be sensitive about where you use the phone to pay your bill. Don't pay bills where others can see what you're typing in, view your card or hear responses you may give to get through automated bill-pay systems.