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History Edit

This method was created by the aops user fdas. It all began in Mafia Game 98: Chess Mafia. fdas forgot his mafia partner gerenjie had the information he was trying to communicate. fdas first decided to bury his message in a long analysis because everyone knows that no one looks through the whole thing. No one did, including gerenjie. Fortunately, gerenjie had the information in the quicktopic. During the night, fdas and gerenjie discussed a new plan that would involve a long analysis and taking the fourth letter of the second word in each response to a quote. In fdas's next game, Mafia Game 102: The Ghastly Game (ASoUE Mafia) he came up with a better strategy. He used spaces in between words to communicate in binary. If there was one space, it is a 0. If there were 2 spaces then it is a 1. This is helped by the fact that AoPS masks the extra spaces so a double space would only show up as a single space unless you quote the post. fdas created a program to encode and decode messages with each letter having a corresponding string of 0s and 1s. This method was very good because not only was it difficult to see, a is not mapped to 1 and b is not mapped to 10... etc so it was difficult to decode. After completing 105, fdas began to think of a better method that would save space.

Space technique Edit

Here is the space technique described in detail:

Collect a long string of 0s and 1s that you want to insert into the text. Go along your post and for every space, add another space if the next number on the list is a 1 and move on to the next space if the next number on the list is a 0. Then, submit your final post which contains the double spaces. AoPS conveniently disregards double spaces and only shows a single space which helps disguise the encoding.

How it works Edit

The current method uses the same space method to encode binary as before. However, the key to decode it would be different. The method would use Huffman Encoding to create a tree that would minimize the amount of 0s and 1s needed to encode a message. The tree would be slightly changed to slightly reduce efficiency but make it harder to crack. One tree would be used for everyone because adding the key makes it take too much space for small messages. Furthermore, the message will be encoded before applying Huffman. After turning the message into 0s and 1s, a 1 and a string of 0s will be added to make sure the amount of 0s and 1s is a multiple of 8. The string is then cut into pieces of 8 and each piece is turned into a character. A cryptogram is then applied to encode it further. Each character is then turned back into 0s and 1s and outputted using the space technique.

Notes Edit

If you wish to have the code, pm fdas on AoPS.

If you find a way to break the code, pm fdas on AoPS.