Encryption Has a Remarkably Long and Varied History

question 30

Multiple Choice

Encryption has a remarkably long and varied history.Spies have been using it to convey secret messages ever since there were secret messages to convey.One powerful method of encryption uses random digits.Two documents are prepared with the same random sequence of numbers.The spy is sent out with one and the spy master retains the other.The digits are used as follows.Suppose that the word to be encrypted is SPY and the random digits are 352.Then S becomes V (three letters after S) ,P becomes U (five letters after P) ,and Y becomes A (two letters after Y,restarting at A after Z) .The spy would encrypt a message and then destroy the document used to encrypt it.This is an early example of

• A)a hashing algorithm.
• B)asymmetric key encryption.
• C)symmetric key encryption.
• D)public key encryption.

---

Definitions:

Weighted Mean

An average in which each quantity to be averaged is assigned a weight, reflecting its importance or frequency.

Geometric Mean

The nth root of the product of n numbers, used to calculate average rates of return or growth over time for variables that fluctuate multiplicatively.

Data Value

A specific piece of information, often numerical, that is collected, analyzed, or stored as part of a data set.

Outlier

A data point that significantly differs from the other data points in a dataset, often indicating a measurement error or a unique case.