A new authentication system that combines phrases with PINs has been launched by online retail giant Amazon.

"PayPhrase" allows buyers to use a single login across multiple sites – those which use the "Checkout by Amazon" payment service.

The system works by picking a phrase, which is then required alongside a four digit PIN to authorise the payment.

Amazon hopes the move will make online shopping easier by removing the need to have multiple logins and passwords.

It's a move becoming increasingly popular as the use of ecommerce sites continues to grow.