Patent ID: 8065233

Claim:
A computer implemented method for processing an online transaction, the method being implemented by one or more programmed electronic computer systems and comprising: generating, by at least one programmed electronic computer system, from an online transaction of a purchaser, a plurality of keys from key fields of the transaction that individually do not reliably identify the purchaser; for each key, retrieving, by at least one programmed electronic computer system, a profile of historical transactions associated with the key; weighting, by at least one programmed electronic computer system, each profile with a weight indicating a degree to which the profile is associated with current purchaser; generating a contrast measure using at least two of the profiles; generating, by at least one programmed electronic computer system, a fraud score indicative of the likelihood of fraud in the online transaction by using the contrast measure, the weighted profiles, and the current transaction; and further processing the online transaction based on the generated fraud score.