Introduction to
Cryptography - D334 SET
EXAM 2024 [VERIFIED
QUESTIONS AND
ANSWERS]..*
XOR the following
0101110101010111
1001100000111010
------------------ - ANSWERS-1100010101101101
asymmetric key-based encryption
-typical methods - ANSWERS-RSA
DSA
El Gamal
Symmetric key-based encryption
-Typical Methods - ANSWERS-RC2- 40 bit key size 64 bit block
RC4- (Stream Cipher)- Used in SSL and WEP
RC5- (Variable Key size, 32, 64, or 128 bit block size)
AES- (128, 192 or 256 bit key size, 128 bit block size)
,DES- (56 bit key size. 64 bit Block size)
3DES- (112 bit key size, 64 bit block size)
Block Encryption - ANSWERS-RC2(40 bit key size)
RC5(Variable block size)
IDEA
DES
3DES
AES (Rijndael)
Blowfish
twofish
stream encryption - ANSWERS-RC4
Chacha
Rainbow Attack - ANSWERS-The method of knowing the mapping between the hashed values
and the original data
Dictionary-type attack - ANSWERS-a brute force analysis
∉ - ANSWERS-does not belong to
when an object is not in a set
,∈ - ANSWERS-Belongs to
when an object is within a set
⊆ - ANSWERS-subset
subset has fewer elements or equal to the set
A ∪ B - ANSWERS-union (objects that belong to set A or set B)
| - ANSWERS-such that
A ∩ B - ANSWERS-Intersection: in both A and B
Enigma Machine -Cypher 10 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-Encoding method, rather than a cipher, that works by
translating characters into sequences of dots (.) and dashes (-)
Playfair Cipher 4 - ANSWERS-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 - ANSWERS-Makes use of a grid and which maps the letters into numeric values.
Rail Code Cipher 2 - ANSWERS-Employs a method to scramble text by writing it in a sequence
across a number of rails.
Pig Pen Cipher 1 - ANSWERS-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 - ANSWERS-in simplest terms is changing plaintext into ciphertext
Decryption - ANSWERS-The process of converting a ciphertext into plaintext.
Cryptography - D334 SET
EXAM 2024 [VERIFIED
QUESTIONS AND
ANSWERS]..*
XOR the following
0101110101010111
1001100000111010
------------------ - ANSWERS-1100010101101101
asymmetric key-based encryption
-typical methods - ANSWERS-RSA
DSA
El Gamal
Symmetric key-based encryption
-Typical Methods - ANSWERS-RC2- 40 bit key size 64 bit block
RC4- (Stream Cipher)- Used in SSL and WEP
RC5- (Variable Key size, 32, 64, or 128 bit block size)
AES- (128, 192 or 256 bit key size, 128 bit block size)
,DES- (56 bit key size. 64 bit Block size)
3DES- (112 bit key size, 64 bit block size)
Block Encryption - ANSWERS-RC2(40 bit key size)
RC5(Variable block size)
IDEA
DES
3DES
AES (Rijndael)
Blowfish
twofish
stream encryption - ANSWERS-RC4
Chacha
Rainbow Attack - ANSWERS-The method of knowing the mapping between the hashed values
and the original data
Dictionary-type attack - ANSWERS-a brute force analysis
∉ - ANSWERS-does not belong to
when an object is not in a set
,∈ - ANSWERS-Belongs to
when an object is within a set
⊆ - ANSWERS-subset
subset has fewer elements or equal to the set
A ∪ B - ANSWERS-union (objects that belong to set A or set B)
| - ANSWERS-such that
A ∩ B - ANSWERS-Intersection: in both A and B
Enigma Machine -Cypher 10 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-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 - ANSWERS-Encoding method, rather than a cipher, that works by
translating characters into sequences of dots (.) and dashes (-)
Playfair Cipher 4 - ANSWERS-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 - ANSWERS-Makes use of a grid and which maps the letters into numeric values.
Rail Code Cipher 2 - ANSWERS-Employs a method to scramble text by writing it in a sequence
across a number of rails.
Pig Pen Cipher 1 - ANSWERS-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 - ANSWERS-in simplest terms is changing plaintext into ciphertext
Decryption - ANSWERS-The process of converting a ciphertext into plaintext.
