2021from public repositories
RTN 2021
10 challenges with 14 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 liveCryptography5
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
Clavdivs
2 official solutionsMixitup
2 official solutionsRehasher
2 official solutionsSsssecret
2 official solutionsNoncense
1 official solution
Forensics2
Recover something from a file, a capture, or a disk image - often from a part of it the format says is unused.
Solve it with:File type identifier by magic bytesMagic byte and file signature tablePCAP analyzer for CTF network forensicsEXIF metadata viewerLearn: File forensics and carvingLearn: Network forensics
Dragons
1 official solutionUnknown File
1 official solution
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
Matryoshka
1 official solutionWebcat
1 official solution
Uncategorised1
The upstream scoreboard did not say, so neither do we.
Lambdastic
1 official solution