cybersecurity 4.1

ciphertext

ciphertext

The encrypted message generated by a cipher

Steganography

Concealing messages with other data

modulus/mod

operation finds the remainder of a division, used in ceasar and affine cipher

substitution cipher

when each letter in an alphabet is replaced with a different character or symbol

encryption key

A string of characters used as a parameter that determines the output of an encryption algorithm

private/symmetric key encryption

an encryption method where the sender and receiver share a single private key

cipher

an algorithm used for encryption or decryption

cryptography

The science and art of delivering a message securely and confidentially

plaintext

The original message that needs to be encrypted

public/asymmetric key encryption

an encryption method that uses two keys, a public key available to everyone and a private key belonging to one owner.

ALGORITHM

steps needed to accomplish a task

What is the difference between “Sign and Encrypt”, “Encrypt” and “Sign”?

With encrypt, you’re using a public key and the receiver will have to use their private key to decrypt the message. With sign, the opposite of encrypt is happening, I’ll be using my private key and the receiver will be using my public key.

one-way function

a math function that is easy to do but very hard to undo.

statements that are true about symmetric encryption.

It has a large key space

statements that are true about symmetric encryption.

It exchanges one shared key.

statements that are true about symmetric encryption.

It uses a relatively simple and fast algorithm.

statements that are true about asymmetric encryption.

It uses a relatively smaller key space.

statements that are true about asymmetric encryption.

It is more secure because of the privately held keys.

statements that are true about asymmetric encryption.

It is relatively slow due to its more complex calculations.

statements that are true about asymmetric encryption.

It can be used for encrypting and signing a message.

Data at rest

Data that’s stored somewhere else; ex: bank account

Data in transit

data that’s being transferred between applications,host or around the network; ex: an email on its way to a recipient; the results coming back from an internet search

Data in process

data that is manipulated by an application; ex: A website calculating the tax of an item

TRUSTED PLATFORM MODULE

mechanism that provides secure encryption for a device

How do recovery keys and hash values differ

Recovery keys are created by the operating system to store the key to the drive, in the event a password is lost. \n Hash values are created at encryption time and represent passwords that control access to the encrypted data.

Disks

physical drives inside of a pc

volume

the accessible storage area on a hard drive or disk

Partition

a part of a volume that's formatted for the operating system to use as a storage area

container

a file that has other data and acts like a drive

HASH

a computational process that converts data of varying size to a fixed-size.

CRYPTOCURRENCY

A digital cash system

what can be encrypted to secure data at rest?

• Entire disk drives

what can be encrypted to secure data at rest?

• Portions of disk drives, such as containers

what can be encrypted to secure data at rest?

• Individual files

what can be encrypted to secure data at rest?

Application specific documents

what happens when you mount vs dismount the container.

When you mount it, the drive is visible in file explorer, but when you dismount it, it is no longer visible

With all of these historical examples of writing, what are the limitations?

• Today, computer algorithms could quickly discover patterns and find the hidden data.

With all of these historical examples of writing, what are the limitations?

• Messages and keys could be discovered by outsiders.

covert

messages that we want to keep hidden

overt

messages that you don’t mind if people can see

SUBSTITUTION STEGANOGRAPHY

Substitution just replaces data that isn’t important or redundant information with the covert data.

ALTERNATE DATA STREAMS

Files can be separated into multiple resources, so you can attach an icon to a file and the icon will be stored with the file.

STEGANALYSIS

the process of analyzing data for hidden content