2026 QUESTIONS AND STUDY GUIDE COMPLETE &
ACCURATE FINAL EXAM , ACTUAL QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(100% CORRECT VERIFIED SOLUTIONS) CURRENTLY
UPDATED VERSION 2026 EDITION |GUARANTEED PASS
2026-2027
A∩B
Intersection: in both A and B
Enigma Machine -Cypher 10
Used a polyalphabetic substitution cipher, which did not repeat
within a reasonable time period, along with a secret key. For the
cracking of the Enigma cipher, the challenge was thus to
determine both the algorithm used and the key. Enigma's main
weakness, though, was that none of the plain text letters could be
ciphered as itself.
Four-square cipher9
Uses four 5 × 5 matrices arranged in a square, are where each matrix
contains 25 letters for encoding and decoding operations.
,One-time pad cypher8
Cypher Code mapping that is only used once.
Advantage: it is essentially unbreakable.
Disadvantage: it takes lots of work as you would have to generate
the pad to be used, each time.
Vigenere Cipher 7
Polyalphabetic cipher that involves using a different mapping, based
on a keyword, for each character of the cipher. An advantage of
this type of
cipher is that the same plaintext character is likely to be coded to
different mappings, depending on the position of the keyword,
making guessing more difficult.
Ceasar Cipher6
Mono-alphabetic substitution cipher known as "shift" cipher. Involves
plaintext being replaced by a letter some fixed number of positions
down the alphabet. i.e., a Caesar Cipher using a shift of +3 would
mean a plaintext letter A would result in a ciphertext letter D (a shift
of three positions to the right in the alphabet)
Morse Code cipher 5
Encoding method, rather than a cipher, that works by translating
characters into sequences of dots (.) and dashes (-)
Playfair Cipher 4
5 × 5 matrix containing the alphabet less the letter J. Cipher/decipher
process consists of a set of rules outlining use of column and row
combinations.
,BIFID Cipher 3
Makes use of a grid and which maps the letters into numeric values.
Rail Code Cipher 2
Employs a method to scramble text by writing it in a sequence across
a number of rails.
Pig Pen Cipher 1
Mono- alphabetic substitution cipher that makes use of mapping
plaintext characters to graphical characters rather than to
alphabetic ones. i.e. A=(pick a symbol), vs A=(pick a letter).
Disadvantage: once the mapping is known, it is difficult to keep
the message secret.
Encryption
in simplest terms is changing plaintext into ciphertext
Decryption
The process of converting a ciphertext into plaintext.
AESCrypt
Encrypt individual files and encrypt full disks with options such as
Bitlocker and FileVault
, Mono-alphabetic
c code or substitution is where a single mapping from our alphabet
to a cipher alphabet is created. Many early cryptosystems used
this.
Polyalphabetic
refers to the mapping of our alphabet to a number of cipher
alphabets. This approach added a bit of complexity to early
cryptosystems.
One-time pad
is considered to be unbreakable since it only uses its cipher code
once.
Pseudo-Random Number Generators (PRNGs)
This method repeats the random numbers after a given time
(periodic). They are fast and are also deterministic and are useful
in producing a repeatable set of random numbers.