2023from public repositories
SpringForward 2023
7 challenges with 21 published solutions between them. CTFtime has no listing for this event at all, so nothing built on CTFtime can show what it was made of. These writeups were found in public repositories instead. Each link is pinned to the commit it was read from.
Where these writeups liveSteganography3
Find the payload hidden inside a carrier that looks ordinary. Bit planes, appended data, metadata, and audio spectrograms.
Solve it with:LSB steganography extractorPNG chunk analyzerAudio spectrogram and SSTV decoderZero-width character and text steganography decoderLearn: Steganography
Backward Time
1 official solutionCrashed Bad
1 official solutionGreat Scott
1 official solution
Cryptography2
Recover a plaintext or a key from something that was supposed to protect it. In practice: identify the scheme, find the parameter the author got wrong, exploit it.
Solve it with:Cipher identifier and automatic decoderVigenere cipher solver with automatic key recoveryRSA decryption and attack runnerWiener’s attack on small RSA private exponentsIn-browser hash cracker with rule transformsLearn: Classical ciphers and frequency analysisLearn: RSA and the parameters that break it
EN WriteUp
8 official solutionsTR WriteUp
8 official solutions
Misc2
Everything that fits no other box: esolangs, puzzles, scripting exercises, and the jail escapes that have not yet earned their own category.
Solve it with:Brainfuck and esolang decoderCipher identifier and automatic decoderRegex tester with match offsets and capture groupsLearn: Recognising encodings
Old Habits Die Hard
1 official solutionStrings Rev
1 official solution