Decentralized automatic phone fraud risk management

A computer-implemented method, the method comprising:

• receiving a first identifier of a first phone event involving a first recipient, by a user device of the first recipient;
• detecting, automatically by the user device without an input of the first recipient, a first behavior of the first recipient with respect to the first phone event;
• automatically determining, by the user device, that the first phone event is a target phone event based on the first behavior of the first recipient detected by the user device;
• and
• adding the first identifier to a list of fraudulent identifiers stored in a blockchain of a blockchain network.

A system, comprising:

• one or more processors;
• and
• one or more computer-readable memories coupled to the one or more processors and having instructions stored thereon that are executable by the one or more processors to, individually or collectively, perform acts including:
• receiving a first identifier of a first phone event involving a first recipient, by a user device of the first recipient;
• automatically detecting, by the user device without an input of the first recipient, a first behavior of the first recipient with respect to the first phone event;
• automatically determining, by the user device, that the first phone event is a target phone event based on the first behavior of the first recipient detected by the user device;
• and
• adding the first identifier to a list of fraudulent identifiers stored in a blockchain of a blockchain network.