Computing - Encryption
What is a summary of encryption?
A way of making sure data cannot be understood if you don’t possess the means to decrypt it.
What is a Ceasar cipher?
A method of encryption where you shift the letters along by a consistent amount.
What is a brute-force attack?
Where you attempt every possible key to decrypt ciphertext until one works.
What is another name for a one-time pad?
A Vernam cipher
What is another name for a Vernam cipher?
A one-time pad
What is a Vernam cipher?
Where a random one-time pad greater or equal in length to the plaintext is exchanged and used to encrypt a message.
What is the advantage to a Vernam cipher?
It is completely unbreakable.
Why can’t you use a one-time pad multiple times?
Because eventually the message will be able to be decrypted with frequency analysis.
What’s an example decoding scheme for a Vernam cipher?
Do an XOR with all the bits of the message and the key.
2022-06-05
What is a digital signature?
A method for ensuring the authenticity of an encrypted message.
How can messages encrypted with a private key be decrypted?
Using the public key.
Why might you want to encrypt something with your private key?
To make a digital signature.
What is typically encrypted with a private key when trying to send a digitally signatured message?
A hash of the message’s contents.
What does a recipient do to check a digital signature accompanying a message?
Hash the message and compare it to the decrypted digital signature using the sender’s public key.