Challenge list
CryptographyLevel 2★★☆☆☆Rainbow Table Attack
Unsalted fast password hashes can often be reversed with precomputed lookup databases. Reverse the given MD5 hash. MD5…
CryptographyLevel 2★★☆☆☆One-Time Pad Key Reuse Attack
A one-time pad is safe only when the key is used once. Reusing the key lets known plaintext recover other plaintexts.…
CryptographyLevel 2★★☆☆☆Predictable Randomness
Pseudo-random output with a fixed seed is reproducible and must not be used for cryptographic secrets. Flag generation…
Digital ForensicsLevel 2★★☆☆☆Recover Deleted Files
Recover the deleted compressed file (ZIP) from the disk image and find the flag in the memo inside it. Learn how to…
CryptographyLevel 2★★☆☆☆Breaking Small RSA Keys
Factor a tiny RSA modulus, recover the private exponent, and decrypt a list of ciphertext values. Public key and…
CryptographyLevel 2★★☆☆☆Cryptanalysis - Breaking the Affine Cipher
ciphertext.txt is an English report encrypted with the affine cipher E(x) = (a*x + b) mod 26. Letter case is preserved…
Digital ForensicsLevel 2★★☆☆☆Message Hidden in Image LSB
Extract the message hidden in the LSB (Least Significant Bit) of a PNG file. Learn the basics of steganography…