PayPal has denied claims it plans to lock Safari users out of its online payments service as it reinforces its protections against online credit fraud.

Although PayPal didn’t officially say that it would be banning transactions on Apple’s Safari browser, many assumed that the online payment service provider included Safari on its list of unsafe browsers since it offered no anti-phishing protection and didn’t support the use of SSL certificates.

PayPal was reacting to reports of a research paper released the week before by Michael Barrett, the firm’s chief information security officer, that said the payment service would ban browsers that lacked a way to block known or suspected phishing sites and didn’t support Extended Validation (EV) certificates.

PayPal might also block other web browsers. At the Usability, Psyschology, and Security Conference 2008 in San Francisco, researchers from the University of California gave a presentation in which they pointed out potential security holes in web browsers on such mobile devices and games consoles as Apple’s iPhone, Nintendo’s Wii and DS.