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Every CTF
2020from public repositories

National Olympaid of Informatics Singapore 2020

7 challenges with 7 published solutions between them. The writeups for this event were found in public repositories. Each link is pinned to the commit it was read from.

Where these writeups live

Uncategorised4

The upstream scoreboard did not say, so neither do we.

Solve it with:Cipher identifier and automatic decoderLearn: Recognising encodings

Cryptography3

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

Other 2020 events