WGU C839 INTRODUCTION TO
CRYPTOGRAPHY EXAM WITH CORRECT
ACTUAL QUESTIONS AND CORRECTLY
WELL DEFINED ANSWERS LATEST
ALREADY GRADED A+ 2025 – 2026
Total break - ANSWERS-The attacker deduces the secret key.
Global deduction - ANSWERS-The attacker discovers a
functionally equivalent algorithm for encryption and
decryption, but without learning the key.
Instance deduction - ANSWERS-The attacker discovers
additional plaintexts or ciphertexts not previously known.
Information deduction - ANSWERS-The attacker gains some
Shannon information about plaintexts or ciphertexts not
previously known.
,Distinguishing Algorithm - ANSWERS-The attacker can
distinguish the cipher from a random permutation.
Verisign - ANSWERS-Certification authority
Class 1 - individuals, intended for email
Class 2 - Organizations which need to provide proof of
identity,
Class 3 - Servers and software signing.
Class 4 - Online business transactions
Class 5 - Private organizations or governmental security.
Affine Cipher - ANSWERS-single substitution cipher. Each
letter is mapped to a numerical value, permuted with a
math function and then converted back to a letter.
Affine cipher formula - ANSWERS-ax + b (mod M)
ROT13 - ANSWERS-One type of substitution cipher in which
the entire alphabet is rotated 13 characters.
Scytale - ANSWERS-Physical cylinder used to encrypt
messages. Turning the cylinder produced different ciphers.
,Single substitution weaknesses - ANSWERS-Preserve the
underlying letter and word frequency. A low-end PC is more
than enough to brute force crack a single sub cipher.
Multi-Alphabet Substitution - ANSWERS-Rotates through
various keys.
Cipher disk - ANSWERS-a physical device used to encrypt.
Invented by Leon Alberti in 1466. The cipher disk was
polyalphabetic; each time you turned the disk, you used a
new cipher.
Vignere cipher - ANSWERS-Invented in 1553 by Giovan
Battista Bellaso. A method of encrypting text by applying a
series of different mono-alphabet ciphers based on the
letters of a keyword.
Playfair Cipher - ANSWERS-Invented by Charles Wheatstone
in mid 1800s. Lord Playfair pushed use of it. Uses a 5x5 table
and a key word. Rest of the alphabet is placed on table in
alphabetic order, skipping letters used in the keyword. You
break up the message into two character chunks and return
a single character value. If the letters appear on the same
, row of your table, replace them with the letters to the right.
If it is on the same column, replace them with the letters
below.
ADFGX Cipher - ANSWERS-First cipher used by the German
army during WWI. Uses a modified Polybus 6 x 6 square.
Single columnar transposition, 36 letter alphabet.
Polybus square - ANSWERS-A 6 x 6 square, used by the
ADFGVX cipher. The letters ADFGVX are used as coordinates
for the square.
Homophonic substitution - ANSWERS-attempt to make
substitution ciphers more robust by masking the letter
frequencies.
nomenclator - ANSWERS-Combines a codebook that had a
table of homophonic substitutions.
Cryptography - ANSWERS-The science of altering
communication so that it cannot be understood without
having the key.
CRYPTOGRAPHY EXAM WITH CORRECT
ACTUAL QUESTIONS AND CORRECTLY
WELL DEFINED ANSWERS LATEST
ALREADY GRADED A+ 2025 – 2026
Total break - ANSWERS-The attacker deduces the secret key.
Global deduction - ANSWERS-The attacker discovers a
functionally equivalent algorithm for encryption and
decryption, but without learning the key.
Instance deduction - ANSWERS-The attacker discovers
additional plaintexts or ciphertexts not previously known.
Information deduction - ANSWERS-The attacker gains some
Shannon information about plaintexts or ciphertexts not
previously known.
,Distinguishing Algorithm - ANSWERS-The attacker can
distinguish the cipher from a random permutation.
Verisign - ANSWERS-Certification authority
Class 1 - individuals, intended for email
Class 2 - Organizations which need to provide proof of
identity,
Class 3 - Servers and software signing.
Class 4 - Online business transactions
Class 5 - Private organizations or governmental security.
Affine Cipher - ANSWERS-single substitution cipher. Each
letter is mapped to a numerical value, permuted with a
math function and then converted back to a letter.
Affine cipher formula - ANSWERS-ax + b (mod M)
ROT13 - ANSWERS-One type of substitution cipher in which
the entire alphabet is rotated 13 characters.
Scytale - ANSWERS-Physical cylinder used to encrypt
messages. Turning the cylinder produced different ciphers.
,Single substitution weaknesses - ANSWERS-Preserve the
underlying letter and word frequency. A low-end PC is more
than enough to brute force crack a single sub cipher.
Multi-Alphabet Substitution - ANSWERS-Rotates through
various keys.
Cipher disk - ANSWERS-a physical device used to encrypt.
Invented by Leon Alberti in 1466. The cipher disk was
polyalphabetic; each time you turned the disk, you used a
new cipher.
Vignere cipher - ANSWERS-Invented in 1553 by Giovan
Battista Bellaso. A method of encrypting text by applying a
series of different mono-alphabet ciphers based on the
letters of a keyword.
Playfair Cipher - ANSWERS-Invented by Charles Wheatstone
in mid 1800s. Lord Playfair pushed use of it. Uses a 5x5 table
and a key word. Rest of the alphabet is placed on table in
alphabetic order, skipping letters used in the keyword. You
break up the message into two character chunks and return
a single character value. If the letters appear on the same
, row of your table, replace them with the letters to the right.
If it is on the same column, replace them with the letters
below.
ADFGX Cipher - ANSWERS-First cipher used by the German
army during WWI. Uses a modified Polybus 6 x 6 square.
Single columnar transposition, 36 letter alphabet.
Polybus square - ANSWERS-A 6 x 6 square, used by the
ADFGVX cipher. The letters ADFGVX are used as coordinates
for the square.
Homophonic substitution - ANSWERS-attempt to make
substitution ciphers more robust by masking the letter
frequencies.
nomenclator - ANSWERS-Combines a codebook that had a
table of homophonic substitutions.
Cryptography - ANSWERS-The science of altering
communication so that it cannot be understood without
having the key.
