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Plagiarism: Crot Plagiarism Checker

Maintained by Picture of Sergey Butakov Sergey Butakov
This FREE plugin is aimed at digital plagiarism detection: it uncovers assignments copied from peers at the same institution. The module is language independent. Maintainer: Sergey Butakov More information:
Moodle 2.0, 2.1, 2.2

Block is based on document fingerprinting technologies for pair-wise document comparison.

Please note that as of August 01, 2012 the block does not perform global / Internet search due to monetization of Bing search engine API.


A distinctive feature of this plug-in is that all local checkups are happening on your Moodle server without sending any documents outside. Thus, in contrast to other available solutions, the plug-in does not impose any issues related to student intellectual property protection. 


This module is the successor of  Crot for Moodle block: This version is tailored for the plagiarism API in Moodle 2.x.

This is standalone module that doesn't require a connection to the external plagiarism detection service. 

Maintainers: Sergey Butakov, Svetlana Kim

More information:


Screenshot #0


Picture of Sergey Butakov
Sergey Butakov (Lead maintainer)
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  • Picture of Sergey Butakov
    Tue, Dec 24, 2013, 4:25 AM
    Those are Notices, they aren't critical errors.
  • Picture of Bert van der Hooft
    Fri, Dec 27, 2013, 11:56 PM

    Error in moodle 2.5: Coding error detected, it must be fixed by a programmer: Invalid table name {plagiarism_crot_submission_pair}: name is too long. Limit is 28 chars.
  • Picture of Graham Bowman
    Thu, Mar 6, 2014, 7:45 AM
    I know it's not officially supported but I tried this plugin on Moodle 2.6.1
    It is giving an error of:
    Strict Standards: Declaration of plagiarism_plugin_crot::get_form_elements_module() should be compatible with plagiarism_plugin::get_form_elements_module($mform, $context, $modulename = '') in /var/www-dev/moodle/plagiarism/crot/lib.php on line 37

    I'm not sure what this error means to start fixing it.
  • Picture of Graham Bowman
    Thu, Mar 6, 2014, 8:00 AM
    I've managed to get the plugin working. I think partly it was that I hadn't used it before so didn't know what to expect.

    I made a new assignment and submitted 2 fake but similar entries and it identified high % similarities. There are all sorts of dubugging errors but the functionality seems to work.
  • Picture of Daniel Villareal
    Mon, Mar 24, 2014, 11:01 PM
    Hi to all, if you want to work the global search of crot let's make a collaboration thank you :D
  • Picture of Sergey Butakov
    Mon, Mar 24, 2014, 11:12 PM
    which search engine are you planning to use?
  • Picture of Paulo Henrique Souto Maior Serrano
    Tue, Jun 17, 2014, 11:29 AM
    Anybody tried it on Moodle 2.7 ? Is it working well ?
  • Picture of sher shahraz
    Tue, Apr 7, 2015, 6:05 PM
    unable to access crotpro/settings.php

  • Picture of sher shahraz
    Tue, Apr 7, 2015, 6:05 PM
  • Picture of Daniel Kim
    Mon, Apr 27, 2015, 8:55 PM
    Have never used some kind of plagiarism checkers, it is good that now everyone is able to use plug-in plagiarism detectors. Before this one I only used paid checkers and
  • Picture of Thanuci Silva
    Wed, Sep 16, 2015, 11:59 PM
    Am I able to use this plugin for moodle assignments written in Portuguese?
  • Picture of Sergey Butakov
    Thu, Sep 17, 2015, 1:54 AM
    yes, its language independent.
  • Picture of Blair F.
    Fri, Sep 18, 2015, 1:07 AM
    Any plans to update this for newer Moodle versions? I tried installing in 2.8 and get the following errors. Unfortunately, I'm now stuck on the plugins check page. Whoops. Good thing it's our test site. smile

    Coding error detected, it must be fixed by a programmer: Invalid table name {plagiarism_crot_submission_pair}: name is too long. Limit is 28 chars.

    Debug info:
    Error code: codingerror
    Stack trace:

    line 287 of /lib/ddl/sql_generator.php: coding_exception thrown
    line 209 of /lib/ddl/mysql_sql_generator.php: call to sql_generator->getCreateTableSQL()
    line 248 of /lib/ddl/sql_generator.php: call to mysql_sql_generator->getCreateTableSQL()
    line 409 of /lib/ddl/database_manager.php: call to sql_generator->getCreateStructureSQL()
    line 364 of /lib/ddl/database_manager.php: call to database_manager->install_from_xmldb_structure()
    line 502 of /lib/upgradelib.php: call to database_manager->install_from_xmldb_file()
    line 1628 of /lib/upgradelib.php: call to upgrade_plugins()
    line 434 of /admin/index.php: call to upgrade_noncore()
  • Picture of Sergey Butakov
    Fri, Sep 18, 2015, 1:27 AM
    There is an easy fix for that. just check forum
  • Picture of Blair F.
    Fri, Sep 18, 2015, 1:47 AM
    Sorry, but I don't see any "easy" fix in the forum (which, for those trying to find it is here: . The only thing I found required changes to xmldb_table.php . Was that what you were referring to? That's not something I have access to, so I guess this plugin is not usable for us, unfortunately. I'll keep my eyes open for an official update to the plugin.
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