Payment Authorization System

1 . A method of determining a required level of authentication for a candidate transaction initiated between a candidate consumer and a merchant system via a payment system, the method comprising, at the payment system, the steps of:

i. receiving candidate transaction data relating to the candidate transaction and user data relating to an identity of the candidate consumer registered with the payment system;

ii. identifying related transaction data for other transactions by other consumers registered with the payment system and having a predetermined relationship with the candidate consumer; and

iii. determining a level of authentication of the candidate consumer required to authorize the candidate transaction based on the related transaction data.

2 . The method of claim 1 , wherein the predetermined relationship comprises an explicit social relationship derived from at least one electronic social network system.

3 . The method of claim 1 , wherein the predetermined relationship comprises an implicit social relationship derived from consumer data.

4 . The method of claim 3 , wherein the implicit social relationship is derived from consumer transaction data.

5 . The method of claim 1 , wherein the required level of authentication is based on a correlation between one or more predetermined factors of the candidate transaction and the other transactions.

6 . The method of claim 5 , wherein the one or more predetermined factors comprise an identity of a merchant, a type of goods or services to be purchased, a geographical location of the candidate consumer, and/or a time of the candidate transaction.

7 . The method of claim 1 , wherein the merchant system comprises an online purchasing system.

8 . The method of claim 1 , wherein the merchant system comprises a point-of-sale system.

9 . The method of claim 1 , wherein the payment system indicates the required level of authentication to the merchant system.

10 . A system of determining a required level of authentication for a candidate transaction initiated between a candidate consumer and a merchant system via a payment system, the system comprising:

an authentication module receiving candidate transaction data relating to the candidate transaction and user data relating to an identity of the candidate consumer registered with the payment system;

the authentication module identifying related transaction data for other transactions by other consumers registered with the payment system and having a predetermined relationship with the candidate consumer; and

a confidence determiner determining a level of authentication of the candidate consumer required to authorize the transaction, based on the related transaction data.

11 . The system of claim 10 , wherein the predetermined relationship comprises an explicit social relationship derived from at least one electronic social network system or an implicit social relationship derived from consumer data.

12 . The system of claim 11 , wherein the implicit social relationship is derived from consumer transaction data.

13 . The system of claim 10 , wherein the required level of authentication is based on a correlation between one or more predetermined factors of the candidate transaction and the other transactions.

14 . The system of claim 13 , wherein the one or more predetermined factors comprises an identity of the merchant, a type of goods or services to be purchased, a geographical location of the consumer, and/or a time of the transaction.

15 . The system of claim 10 , wherein the merchant system comprises an online purchasing system or a point-of-sale system.

16 . The method of claim 10 , wherein the payment system indicates the required level of authentication to the merchant system.