The Athletic: Here’s a homemade version of the Codebreaker algorithm — and how to break it

From C. Trent Rosecrans and SABR members Eno Sarris and Jayson Stark at The Athletic on March 18, 2020:

You, too, can be a state-of-the-art sign-stealer.

You can play along at home and download The Athletic’s homemade version of the sign-cracking algorithm, while we take a look at how actual major leaguers defended themselves against the Astros’ program.

“Codebreaker” was the name members of the Astros front office used to refer to the algorithm that cracked opponent’s signs, an algorithm that was eventually misused by the players to steal signs electronically during the game.

“The Codebreaker system, in and of itself, could have been perfectly legal,” commissioner Rob Manfred said. “In other words, it started as a non-in-game effort to decode signs. Lots and lots of teams do that. It does not violate our rules.”

When The Wall Street Journal dropped quotes from the Manfred letter that provided details about the program, the report jogged loose a simple question for The Athletic co-founder Adam Hansmann: “Can we do that?”

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Originally published: March 19, 2020. Last Updated: March 19, 2020.