What?
Encryption where everyone that wants to read the message, has the same key.
What makes a secure encryption?
- Ideally an enemy can’t make their own secret key.
- Ideally an enemy can’t recover the entire plaintext m.
- Ideally an enemy can’t recover any of the plaintext m.
The attacker may have access to:
- Some plaintext
- Some cipher text / plain text pairs
- They may have access to the encryptor (encryption oracle) that can encrypt plain text.
- They likely would only have a realistic amount of compute.
WTF do we do with Keys?
Good question lol.
What’s Malleability in Encryption:
If an attacker can change the ciphertext in such a way that it predictably changes the then decrypted plaintext, the encryption is malleable.