What is cryptography?
Q: What is cryptography?
A: Cryptography, or cryptology, is the practice and study of hiding information. It involves a mix of mathematics, computer science, and electrical engineering to keep information secret and safe.
Q: How is cryptography used?
A: Cryptography is used in ATM (bank) cards, computer passwords, and shopping on the internet. When a message is sent using cryptography it is changed (or encrypted) before it is sent.
Q: What does changing text with cryptography involve?
A: Changing text with cryptography involves using a "code" or "cipher". The changed text is called "ciphertext". This makes the message hard to read so someone must change it back (or decrypt it).
Q: What do you call studying the cyphertext to discover the secret?
A: Studying the cyphertext to discover the secret is called "cryptanalysis" or "cracking" or sometimes "code breaking".
Q: What type of key do ciphers use?
A: Ciphers use a "key" which is a secret that hides the secret messages.
Q: How many keys does Caesar's cipher have?
A: Caesar's cipher has only as many keys as there are letters in the alphabet so it can be easily cracked by trying all possible keys.
Q: How did computers become involved in cryptography during the 20th century?
A: During the 20th century computers became an important tool for cryptography because they allowed for more complex methods of cracking ciphers that allow billions of keys.
