Apple will launch its Apple Pay mobile payment system on Monday, Oct. 20, and now has support from an additional 500 banks since it was announced in early September.

The new system was initially announced at an event Sept. 9, but no launch date was confirmed until today, Oct. 16, when Apple debuted its new iPads and iMacs.

"We believe Apple Pay is going to be huge. It's going to change the way we pay for things," said CEO Tim Cook at today's event. "And I'm excited to announce today that we are beginning on Monday."

Apple Pay isn't just going to launch Oct. 20, but it will launch with many more partners than first announced. Along with 500 more banks, Apple is partnering with more retailers, which will expand the consumer opportunity to use Apple Pay.

"We're getting going in the United States, we've got all 3three major networks supporting us and we have all of the nation's top banks supporting us and just since last month, announcing this, we have signed another 500 banks," continued Cook. "They will be rolling out support later this year and early next year showing the support and the enthusiasm around Apple Pay. We've got many of the largest retailers around the country supporting us and as you might guess since we announced last month, there's even more that will be rolling out between now and the end of the year."

Apple Pay is not just a way to pay for things in retail stores and banks, however. The system is also usable within a number of supported apps, allowing users to buy things using Apple Pay straight from a phone.

"Apple Pay also works online. In apps you can buy products and services right in the app and it's pretty simple," said Cook.

Apple Pay has garnered a lot of attention for a number of reasons, not all of them positive. Apple recently suffered a big blow in the consumer trust department after hundreds of female celebrities' iCloud accounts were hacked and nude photos were posted online.

Despite this, many note Apple Pay makes use of a number of security methods to ensure users do not have money stolen. First of all, the data being transferred is completely encrypted. The transfer does not even use credit card numbers, but instead uses a unique token that is changed with every transfer that is made.

"Apple Pay is an entirely new way to pay for things in stores and in apps," Cook said at the event. "It's easy, it's secure and, yes, it's a private way to pay for things. We think that it is going to be profound."

Apple Pay uses near-field communication chips, a secure wireless technology that can send payments from a phone to a special reader in a store. Customers wave their phone near a reader, then confirm the purchase with the Touch ID fingerprint sensor on the phone. No card numbers are shared with the stores.