Introduction to Cryptography

Prompts and answers

• You can guess that it is a quote. Who said it?
  Miyamoto Musashi
• Decrypt the file quote01 encrypted (using AES256) with the key s!kR3T55 using gpg. What is the third word in the file?
  waste
• Decrypt the file quote02 encrypted (using AES256-CBC) with the key s!kR3T55 using openssl. What is the third word in the file?
  science
• Decrypt the file quote03 encrypted (using CAMELLIA256) with the key s!kR3T55 using gpg. What is the third word in the file?
  understand
• Bob has received the file ciphertext_message sent to him from Alice. You can find the key you need in the same folder. What is the first word of the original plaintext?
  Perception
• Take a look at Bob’s private RSA key. What is the last byte of p?
  e7
• Take a look at Bob’s private RSA key. What is the last byte of q?
  27
• A set of Diffie-Hellman parameters can be found in the file dhparam.pem. What is the size of the prime number in bits?
  4096
• What is the prime number’s last byte (least significant byte)?
  4f
• What is the SHA256 checksum of the file order.json?
  2c34b68669427d15f76a1c06ab941e3e6038dacdfb9209455c87519a3ef2c660
• Open the file order.json and change the amount from 1000 to 9000. What is the new SHA256 checksum?
  11faeec5edc2a2bad82ab116bbe4df0f4bc6edd96adac7150bb4e6364a238466
• Using SHA256 and the key 3RfDFz82, what is the HMAC of order.txt?
  c7e4de386a09ef970300243a70a444ee2a4ca62413aeaeb7097d43d2c5fac89f
• What is the size of the public key in bits?
  4096
• Till which year is this certificate valid?
  2039
• You were auditing a system when you discovered that the MD5 hash of the admin password is 3fc0a7acf087f549ac2b266baf94b8b1. What is the original password?
  qwerty123