Cryptography and Encryption

Hash Function

A function used in order to create a unique hash for a message.

Secret Key Cryptography

A type of cryptography where both users use a secret key value in order to encrypt and decrypt data sent.

What makes the Advanced Encryption Standard (DES) so much better than the old Data Encryption Standard (DES)?

AES uses a key cipher with 128, 192, and 256 keys. This means even supercomputers will take billions of years to crack AES, while they can crack DES in a matter of minutes.

What replaced the Data Encryption Standard (DES)?

Advanced Encryption Standard (AES)

What is the term for when we use more than one key?

Asymmetric Encryption

What is Authentication?

Authentication is how you verify who is communicating with you over the network. This protects users by making sure that they are communicating with the right person and not someone with malicious intent.

What is used to achieve non-repudiation?

Digital signatures are used in non repudiation.

What is Non-Repudiation?

Non-repudiation is how you make sure that someone cannot deny something that happened the network. This helps keep track of every action over the network, such as who sent a message and where the message came from.

Are all versions of SSL/TLS Unbreakable?

Older versions of SSL/TLS are not breakable, and this is especially true in email, when email servers maybe be using older versions, leaving you open to hackers.

What is Public Key Cryptography?

Public Key Cryptography involves the sender and receiver each having a private key that is their own, as well as one common public key that they share. In order to encrypt and decrypt data, one must have both the private and the public key.

What are the Three Types of Cryptography?

Secret Key Hash Functions Public Key

What does it mean when a website URL starts with https?

That means the website is using some version of Secure Socket Layer (SSL) or Transport Layer Security (TLS).

What is the Data Encryption Standard (DES)?

The Data Encryption Standard (DES) was a standard designed in the 1970s. At the time, it was thought to be unbreakable because it used a 56-bit key, meaning there were 2^56 possible combinations.

What is the basic idea behind Encryption

The basic idea of encryption is to convert some data that a user wants to send over into some form that is unreadable to the human eye. The data is sent over to the receiver in this encrypted from so as to be protected from others while in transit. Finally, the data is decrypted once on the receiver side.

What is the basic idea behind Integrity?

The basic idea of integrity is to ensure that the state of the data is maintained while it is in transit from sender to receiver -- that the data is not modified in any way.

What is the best way to ensure your data stays secure?

The best way to do this is to make sure that your data is encrypted from the moment that it leaves your computer and gets onto the network. So Client-Side Encryption is the key.

What is necessary for encryption and decryption?

The data is encrypted according to some encryption key, and only with this key can one decrypt it. This key is the main force protecting data from outside eyes. In some instances though, a different key may be used for each task.

Why do we use hash functions?

This hash is used to make sure that a message was not tampered with.

What do we typically use to ensure Integrity is maintained?

This is often done through the use of a cryptographic hash.

What is the main problem with the Data Encryption Standard (DES)?

To crack it, one would have to brute force through all 2^56 possibilities. In 1970, this seemed impossible, but modern hardware can easily handle this sort of load.