Here is a RSA private key with its upper part masked. Can your recover the private key and decrypt the file? equation.zip Summary: recovering RSA key from part of the private key.
March 2016 archive
Mar 13
0CTF 2016 Quals – RSA? (Crypto 2 pts)
It seems easy, right? rsa.zip Tip: openssl rsautl -encrypt -in FLAG -inkey public.pem -pubin -out flag.enc Summary: factoring 300-bit modulus into 3 primes, extracting cube roots.
Mar 07
Boston Key Party CTF 2016 – Feistel (Crypto 5pts)
feistel – 5 – 15 solves : crypto: I just made a brand new cipher! Can you recover the key? 52.86.232.163:32785 feistel.go Summary: slide with a twist attack
Mar 07
Boston Key Party CTF 2016 – GCM (Crypto 9pts)
[8] : gsilvis counting magic – 9 – 4 solves : crypto: Here’s a verification/decryption server: gcm.ctf.bostonkey.party:32768 . Get the GCM MAC key (the thing the server prints out on startup). We’ve given you one valid ciphertext to get you started. It has iv: [102 97 110 116 97 115 116 105 99 32 105 …
Mar 07
Boston Key Party CTF 2016 – HMAC-CRC (Crypto 5pts)
[3] : hmac_crc – 5 – 36 solves : crypto: We’re trying a new mac here at BKP—HMAC-CRC. The hmac (with our key) of “zupe zecret” is ‘0xa57d43a032feb286’. What’s the hmac of “BKPCTF”? hmac-task.py Summary: breaking HMAC-CRC (again)