Assignment4

1. What is the important difference between the public-key cryptography and secret-key cryptography?

The major difference between the public-key cryptography and secret-key cryptography that distinguishes one from the other is the number of keys each uses and how they use it.
The major difference between the public-key cryptography and secret-key cryptography that distinguishes one from the other is the number of keys each uses and how they use it.

In a traditional cryptography, also known as secret-key cryptography or symmetric cryptography, a single key is used by both sender and receiver to encrypt and decrypt data. The key is kept private between the two involved in the communication. Both parties should agree on what key to use before starting the communication.

On the other hand, in a modern cryptography or public-key cryptography or asymmetric cryptography, two keys are used; a public key and a private key. This cryptography is more likely to be used on a data communication wherein the sender and receiver have not yet met or there is no agreement between the two on what key is to be used. The public key is a non-secret key known by those who will be sending a message to a user. It is used by sender to encrypt the data. On the contrary, the private key is only known to a user or the one who will receive the data thus allowing him alone to decrypt and read the message which ensures data integrity.

2. What kinds of information Echelon collects?

Based on some sites concerned with Echelon activities, Echelon collects huge amount of random data and just sort out the interesting stuff or data of used to them using keywords. Since it has been said that Echelon uses these data for national security, then, maybe we could assume the Echelon collects information such as criminal records, suspected terrorists/criminal communications, politics-related data, newly discovered technology or weaponry etc.

3. Describe at least three different kinds of uses of encryption that have social value. Indicate why the are valuable.

• Encryption secures private/personal information of an individual.
• Encryption secures the authenticity and integrity of the data transmitted.
• Encryption or encrypting of data serves as a reminder for everyone involved in data transmission to be responsible and careful enough in keeping or giving out information.
  

The three uses of encryption mentioned above are of great value for it determines how important an encryption could be and how greatly could it affect one’s personal and social being especially to a someone in the field of information technology.