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How a Lecturer Catches Code Translated Between Languages General 11 min
Rachel Foster Rachel Foster · 1 month ago

How a Lecturer Catches Code Translated Between Languages

MOSS and JPlag compare Java to Java and Python to Python, which means a translated submission can score in single digits while the logic stays identical. This is how one lecturer, a TA, and a department chair handle ports, and what they've learned about the tooling that catches them.

Can a Python Submission Be Traced Back to a Java Repository? General 15 min
Alex Petrov Alex Petrov · 1 month ago

Can a Python Submission Be Traced Back to a Java Repository?

Two Python submissions scored 4% against each other and in the 70s against a Java gist from 2017. Cross-language plagiarism is the fastest-growing blind spot in academic integrity because translation destroys the text while preserving everything that matters. Here's what survives a translation, what detectors actually see, and where the false positives come from.

How Code Plagiarism Detection Went From Hashes to LLMs General 11 min
Marcus Rodriguez Marcus Rodriguez · 1 month ago

How Code Plagiarism Detection Went From Hashes to LLMs

Ottenstein's 1976 detector hashed student Fortran token streams, and most of what we run today is a refined version of the same idea. This is the fifty-year arc from line diffs to winnowing, AST matching, web crawling, and statistical AI detection, plus the failure mode that still bites: a 0% similarity score that tells you nothing about authorship.

A Framework for Verifying Code Originality From Contractors General 11 min
Marcus Rodriguez Marcus Rodriguez · 1 month ago

A Framework for Verifying Code Originality From Contractors

Most statements of work say "original work" and never define it, which is how GPL code ends up in your settlement service. Here is the four-question intake review I run on every contractor deliverable, with the thresholds and tooling that hold up under scrutiny.

Token and AST Normalization in Code Similarity Detection General 10 min
David Kim David Kim · 1 month ago

Token and AST Normalization in Code Similarity Detection

Line diffing under-reports copied code and over-reports similar-looking code. Here's what token normalization and AST fingerprinting actually compare, where each one breaks, and how to wire both into a CI pipeline or an academic submission workflow.

How AST Comparison Catches Refactored Code Plagiarism General 12 min
Rachel Foster Rachel Foster · 1 month ago

How AST Comparison Catches Refactored Code Plagiarism

Renaming variables and swapping a for loop for a while loop defeats simple text matching, but it rarely defeats structural comparison. This report walks through the obfuscation ladder, the algorithms that climb it, and the published detection rates behind the claims, including the cases where every engine still misses.

What Cross-Language Code Plagiarism Detection Can and Cannot See General 11 min
James Okafor James Okafor · 1 month ago

What Cross-Language Code Plagiarism Detection Can and Cannot See

Cross-language code plagiarism detection compares normalized structure rather than raw text, which works when a translation was mechanical and fails when the student rewrote the algorithm. Here is what survives a Java-to-Python translation, what the token and IR approaches actually see, and how to run the check across a whole cohort without drowning in false positives.

How Cross-Language Code Plagiarism Detection Works General 13 min
Alex Petrov Alex Petrov · 1 month ago

How Cross-Language Code Plagiarism Detection Works

A Java submission and a Python submission looked nothing alike, but they were the same algorithm translated line by line. This is the story of how cross-language code plagiarism detection actually works, where it catches translated code, and where it still fails.

The Long Road to Refactoring-Resistant Code Plagiarism Detection General 6 min
Alex Petrov Alex Petrov · 1 month ago

The Long Road to Refactoring-Resistant Code Plagiarism Detection

A hands-on retrospective on how code similarity detection grew from naive line diffs to tokenization, ASTs, and fingerprinting. Follow a step-by-step Python prototype and a production workflow with Codequiry to catch refactored plagiarism in CS courses.

How Code Plagiarism Detection Algorithms Ignore Renamed Variables General 9 min
Marcus Rodriguez Marcus Rodriguez · 2 months ago

How Code Plagiarism Detection Algorithms Ignore Renamed Variables

A student renames every variable and converts for loops to while loops. MOSS still flags 94%. This guide builds a minimal winnowing detector in Python 3.11 so you can see exactly why code plagiarism detection algorithms survive refactoring. We then look at where the approach breaks and how AST matching fills the gap.