Decrypting when you are not given the key, i.e., cryptanalysis
Budget: $30 – $250 USD
In your tarball in the withoutkey directory, you’ll find three files:
ciphertext.txt - A ciphertext encrypted with a Caesar cipher.
secretfile.txt.gz.enc - A ciphertext encrypted with Julia’s cipher, as described in Homework 1.2.
sha512sums.txt - sha51sums of the correct answers.
This time you are not provided with any keys. Use the techniques discussed in class to mount ciphertext-only attacks on both of these ciphertexts. Note that Julia’s cipher is not the same as a Vigenere cipher. You’ll need to use the basic insights you learned, but the specifics from the slides won’t be exactly what you’re doing.
You will submit exactly two text files: plaintext.txt (Caesar cipher) and secretfile.txt (Julia’s cipher). They should both be ASCII-encoded English text.
ciphertext.txt - A ciphertext encrypted with a Caesar cipher.
secretfile.txt.gz.enc - A ciphertext encrypted with Julia’s cipher, as described in Homework 1.2.
sha512sums.txt - sha51sums of the correct answers.
This time you are not provided with any keys. Use the techniques discussed in class to mount ciphertext-only attacks on both of these ciphertexts. Note that Julia’s cipher is not the same as a Vigenere cipher. You’ll need to use the basic insights you learned, but the specifics from the slides won’t be exactly what you’re doing.
You will submit exactly two text files: plaintext.txt (Caesar cipher) and secretfile.txt (Julia’s cipher). They should both be ASCII-encoded English text.