بروتوكول "Challenge Handshake Authentication Protocol"(A challenge-response authentication protocol for Point-to-Point Protocol (PPP) connections described in RFC 1994. It uses the industry-standard MD5 hashing algorithm to hash the combination of a challenge string issued by the authenticating server and the user's password in the response)
تحدي وسيلة الدفع(A fraud prevention mechanism that attempts to verify that an individual using a payment instrument is authorized to use or is the owner of that instrument)