Abstract: A communication number processing system and methods for processing communication numbers or identifiers of various types to prevent fraud in transactions associated with the communication numbers are disclosed. The communication number processing system, in an example embodiment, verifies a communication number by retrieving characteristics data including network-derived characteristics data and/or other attributes relating to the communication number and processing the characteristics data and/or the attributes based on one or more rules. The communication number processing system further generates a fraud score for the communication number. A client system can then use the fraud score to assess a risk associated with engaging in a transaction with a user associated with the communication number.