Prevention of unauthorized scripts

A method of conducting a Turing test for a user requesting access to a service provided by a server coupled to a data communication network, said user requesting the service via a client computer system also coupled to the data communication network, said method comprising:

• delivering a first test to the client computer system, said first test comprising a human-readable textual string of characters to be read by the user, said textual string of characters being visually altered to inhibit computerized character recognition;
• delivering a second test to the client computer system as an alternative to the first test, said second test comprising an audible string of characters to be heard by the user;
• delivering a third test to the client computer system as an alternative to the first and second tests, said third test comprising a computational puzzle configured to be executed by the client computer system in a manner requiring a pre-defined minimum amount of time, said first, second, and third tests each having different correct solutions;
• enabling the user to elect between the first, second, and third tests;
• receiving a response to the elected test and providing access based on the received response.

A method of preventing automated access to a service, said method comprising:

• delivering a first human interaction proof challenge and a second human interaction proof challenge to a client coupled to a data communication network in response to a user requesting a service to be provided via the network, said first and second challenges each having a different correct solution;
• requesting that the user elect the first or the second challenge;
• enabling the user to elect a third challenge as an alternative to the first and second challenges, said third challenge including a computational puzzle to be solved by the client;
• receiving via the client a response to the elected challenge;
• storing information representative of one or more previously used challenges;
• comparing the received response to the stored information;
• and
• granting access to the service via the client if the received response is the correct solution to the challenge elected by the user unless the received response corresponds to the stored information.

A method of preventing automated access to a service provided by a server coupled to a data communication network, said method comprising:

• delivering at least three tests for identifying unauthorized scripts, said tests being delivered to a client coupled to the data communication network in response to a user requesting access to the service via the network, said tests each having different correct solutions, and at least one of said tests being elected by the user, said tests being selected from a group consisting of:
• a human-readable textual string of characters to be read by the user, wherein the textual string of characters is visually altered to inhibit computerized character recognition;
• an audible string of characters to be heard by the user;
• and a computational puzzle to be solved by the client;
• sending, to the client, a block of data representative of the correct solutions to the tests together with the tests, said block of data being returned with a response to the elected test from the user;
• receiving the response and the block of data via the network;
• determining whether the received response is valid based on the received response and the received block of data;
• and
• granting access to the service if the received response is valid.

A system for preventing unauthorized access to a service provided via a data communication network comprising:

• a first server coupled to the network, said first server delivering at least three challenges each having different correct solutions to a client also coupled to the network in response to the client requesting access to the service, said tests being selected from a group consisting of:
• a human-readable textual string of characters to be read by a user, wherein the textual string of characters is visually altered to inhibit computerized character recognition;
• an audible string of characters to be heard by the user;
• and a computational puzzle to be solved by the client, said first server sending a block of data to the client together with each of the challenges, said block of data containing information representative of the correct solutions to the challenges;
• and
• a second server coupled to the network, said second server receiving, from the client, a response to at least one of the challenges elected by the client, said second server further receiving the block of data via the client for determining whether the received response is valid before granting access by the client to the service.