EC-Council Certified Encryption Specialist (ECES) –
Questions With Clear Solutions
What is cryptography? Correct Answer - Noun -
A) The process or skill of communicating in or deciphering secret writings or
ciphers
B) Secret writing
Origin -
Cryptography (or cryptology); derived from word kryptos which means
"hidden", and grafo, which means "write", is the study of message secrecy
Definition-
Cryptography is the science of altering communication so that it cannot be
understood without having the key
Interloper Correct Answer - a person who becomes involved in a place
or situation where they are not wanted or are considered not to belong.
History of cryptography Correct Answer - A) Hidden or secret writing is
very old: People have been practicing hidden writing for at least 3,000 years.
B) Until the latter part of the 20th century, cryptography was almost
exclusively used by military and government
Mono-Alphabetic Substitution Correct Answer - A) Most primitive
cryptographic algorithms
B) Substitute one character of cipher text for each character of plain text
C) Caesar Cipher, Atbash Cipher, Affine Cipher, Rot13 Cipher
Caesar Cipher Correct Answer - A) First used by Julius Caesar
B) Every letter is shifted a fixed number of spaces to the left or the right in the
alphabet
C) The shifting is the "key" for this algorithm
D) The shift is often called the "alphabet" being used.
Example "I Like Computers" shift 1 to left becomes "H Khjd Bnlotsdqr"
**Most common single-letter word is "A" and most common three-letter word
is "the". Most common two-letter combinations are "EE" and "OO"**
E) 128-bit number from AES (Advanced Encryption Standard)
,Atbash Cipher Correct Answer - A) Hebrew Code that reverses alphabet.
Example "A" becomes "Z", "B" becomes "Y"... "A cat sleeps" becomes "Z "xzg
hovvkh"
B) Used by Hebrew scribes copying the book of Jeremiah
C) Simple cipher not used in modern times
Affine Cipher Correct Answer - any single-substitution alphabet cipher
(also called mono-alphabet substitution) in which each letter in the alphabet
is mapped to some numeric value, permuted with some relatively simple
mathematical function, and then converted back to a letter
Example**in Caesar cipher, each letter is converted to a number, shifted by a
certain amount, and converted back to a letter**
Basic formula for affine cipher is "ax + b (modM)
M= size of alphabet = 26
x= plain text letter's numeric equivalent
b= shift
a= some multiple, in Caesar cipher = 1
Caesar cipher (using affine cipher)
1x + shift (mod26)
Rot13 Cipher Correct Answer - similar to Caesar cipher, but all letters
are rotated 13 spots
Example "A CAT" becomes "N PNG"
Scytale Correct Answer - A) Cylinder tool used by the Greeks and often
specifically attributed to the Spartans
B) Used to encrypt messages
C) Turning the cylinder produced different cipher texts
D) First used in 7th century BC by Greek poet Archilochus
E) Writer of message wraps parchment around a rod
F) Recipient uses a rod of the same diameter as one used to create message
G) Requires both parties to have same size rod, and same leather "key"
Single Substitution Weaknesses Correct Answer - A) Easy to break
B) Easily susceptible to brute force attacks, even by low end computers
Multi-Alphabet Substitution Correct Answer - A) Also called "Poly-
Alphabet Substitution"
,B) Use of more than 1 alphabet in a cipher. (to make ciphers like Caesar and
Atbash more secure)
Example: With +1 -1 +2 since you add 1 to the first letter, subtract 1 from the
second letter, add 2 to the third letter, resets on the fourth letter... "A CAT"
becomes "B BCA"
C) Examples of "Poly-Alphabet Substitution" ciphers are: Cipher Disk,
Vigenere, and Enigma Machine
Cipher Disk Correct Answer - A) Uses a physical device to encrypt (like
scytale)
B) Invented by Leon Alberti in 1466
C) Physical disk, each time you turned disk...you created a new cipher
D) Literal disk used to encrypt plain text
Vigenere Cipher Correct Answer - A) Most widely known Poly-alphabet
cipher
B) Created in 1553 by Giovan Battista Bellaso...misattributed to Blaise de
Vigenere
C) Encrypted using a table and set of mono-alphabet ciphers using keyword
D) Used in 1800 and 1900s
Example:
Breaking the Vigenere Cipher Correct Answer - A) First person to break
Vigenere Cipher was Friedrich Kaiski in 1863
Playfair Cipher Correct Answer - A) Invented in 1854 by Charles
Wheatstone...named after Lord Playfair who promoted its use
B) uses five-by-five table containing a keyword or key phrase. To generate the
key table, one would first fill in the spaces with the keyword (dropping
duplicates), then filled rest of spaces with letters from alphabet in order
C) to encrypt a message, you would break message into groups of two letters.
("CheeseBurger" becomes "Ch ee se Bu rg er")
ADFGVX Cipher Correct Answer - A) The first chiper used by the German
Army during World World I
B) Invented by Colnel Fritz Nebel in 1918
C) Transposition cipher which used: A modified Polybius square, A single
columnar transposition, and a 36 letter alphabet
D) Extension of an earlier cipher called ADFGX
, Homophonic Substitution Correct Answer - A) One of the earlier
attempts to make substitution ciphers more robust by masking the letter
frequencies. Plain text letters map to more than 1 cipher text symbol
B) Having a single character of plain text map to more than 1 character of
cipher text makes it more difficult to analyze homophonic substitution
ciphers.
C) The nomenclator combined a codebook that had a table of homophonic
substitutions
D) Originally the codebook used names of poeple, thus the term "nomenclator.
Example *Mr. Smith could be XX, and Mr. Jones could be XYZ*
Null Ciphers Correct Answer - A) message is hidden in unrelated text.
Example *sending a message like "We are having breakfast at noon at the cafe.
Would that be ok?"*
B) Sender and recipient have prearranged to use a pattern, taking letters from
the message. Example *3, 20, 22, 27, 32, 48* would produce the word "attack"
Rail Fence Ciphers Correct Answer - A) May be the most widely known
transposition cipher.
B) You take down the message you want to encrypt and alter each letter on a
different row
Example* The message "Attackatdawn" or "Attack at dawn" is written as
Atcadw
taktan*
C) Next you take it and write it out from left to right
Example *Atcadwtaktan*
D) To decrpyt, reverse the steps
E) Most texts use two rows, but it can be done with any number of rows
The Enigma Machine Correct Answer - A) In World War II, the Germans
made use of an electromechanical rotor based cipher system known as The
Enigma Machine
B) Designed so that when the operator pressed a key the encrypted cipher
text for that plain text was different each time
Example *When the operator pressed the "A" key, it might generate an "F" this
time, and might generate a "D" next time*
C) Multi-alphabet cipher consisting of 26 possible alphabets
Questions With Clear Solutions
What is cryptography? Correct Answer - Noun -
A) The process or skill of communicating in or deciphering secret writings or
ciphers
B) Secret writing
Origin -
Cryptography (or cryptology); derived from word kryptos which means
"hidden", and grafo, which means "write", is the study of message secrecy
Definition-
Cryptography is the science of altering communication so that it cannot be
understood without having the key
Interloper Correct Answer - a person who becomes involved in a place
or situation where they are not wanted or are considered not to belong.
History of cryptography Correct Answer - A) Hidden or secret writing is
very old: People have been practicing hidden writing for at least 3,000 years.
B) Until the latter part of the 20th century, cryptography was almost
exclusively used by military and government
Mono-Alphabetic Substitution Correct Answer - A) Most primitive
cryptographic algorithms
B) Substitute one character of cipher text for each character of plain text
C) Caesar Cipher, Atbash Cipher, Affine Cipher, Rot13 Cipher
Caesar Cipher Correct Answer - A) First used by Julius Caesar
B) Every letter is shifted a fixed number of spaces to the left or the right in the
alphabet
C) The shifting is the "key" for this algorithm
D) The shift is often called the "alphabet" being used.
Example "I Like Computers" shift 1 to left becomes "H Khjd Bnlotsdqr"
**Most common single-letter word is "A" and most common three-letter word
is "the". Most common two-letter combinations are "EE" and "OO"**
E) 128-bit number from AES (Advanced Encryption Standard)
,Atbash Cipher Correct Answer - A) Hebrew Code that reverses alphabet.
Example "A" becomes "Z", "B" becomes "Y"... "A cat sleeps" becomes "Z "xzg
hovvkh"
B) Used by Hebrew scribes copying the book of Jeremiah
C) Simple cipher not used in modern times
Affine Cipher Correct Answer - any single-substitution alphabet cipher
(also called mono-alphabet substitution) in which each letter in the alphabet
is mapped to some numeric value, permuted with some relatively simple
mathematical function, and then converted back to a letter
Example**in Caesar cipher, each letter is converted to a number, shifted by a
certain amount, and converted back to a letter**
Basic formula for affine cipher is "ax + b (modM)
M= size of alphabet = 26
x= plain text letter's numeric equivalent
b= shift
a= some multiple, in Caesar cipher = 1
Caesar cipher (using affine cipher)
1x + shift (mod26)
Rot13 Cipher Correct Answer - similar to Caesar cipher, but all letters
are rotated 13 spots
Example "A CAT" becomes "N PNG"
Scytale Correct Answer - A) Cylinder tool used by the Greeks and often
specifically attributed to the Spartans
B) Used to encrypt messages
C) Turning the cylinder produced different cipher texts
D) First used in 7th century BC by Greek poet Archilochus
E) Writer of message wraps parchment around a rod
F) Recipient uses a rod of the same diameter as one used to create message
G) Requires both parties to have same size rod, and same leather "key"
Single Substitution Weaknesses Correct Answer - A) Easy to break
B) Easily susceptible to brute force attacks, even by low end computers
Multi-Alphabet Substitution Correct Answer - A) Also called "Poly-
Alphabet Substitution"
,B) Use of more than 1 alphabet in a cipher. (to make ciphers like Caesar and
Atbash more secure)
Example: With +1 -1 +2 since you add 1 to the first letter, subtract 1 from the
second letter, add 2 to the third letter, resets on the fourth letter... "A CAT"
becomes "B BCA"
C) Examples of "Poly-Alphabet Substitution" ciphers are: Cipher Disk,
Vigenere, and Enigma Machine
Cipher Disk Correct Answer - A) Uses a physical device to encrypt (like
scytale)
B) Invented by Leon Alberti in 1466
C) Physical disk, each time you turned disk...you created a new cipher
D) Literal disk used to encrypt plain text
Vigenere Cipher Correct Answer - A) Most widely known Poly-alphabet
cipher
B) Created in 1553 by Giovan Battista Bellaso...misattributed to Blaise de
Vigenere
C) Encrypted using a table and set of mono-alphabet ciphers using keyword
D) Used in 1800 and 1900s
Example:
Breaking the Vigenere Cipher Correct Answer - A) First person to break
Vigenere Cipher was Friedrich Kaiski in 1863
Playfair Cipher Correct Answer - A) Invented in 1854 by Charles
Wheatstone...named after Lord Playfair who promoted its use
B) uses five-by-five table containing a keyword or key phrase. To generate the
key table, one would first fill in the spaces with the keyword (dropping
duplicates), then filled rest of spaces with letters from alphabet in order
C) to encrypt a message, you would break message into groups of two letters.
("CheeseBurger" becomes "Ch ee se Bu rg er")
ADFGVX Cipher Correct Answer - A) The first chiper used by the German
Army during World World I
B) Invented by Colnel Fritz Nebel in 1918
C) Transposition cipher which used: A modified Polybius square, A single
columnar transposition, and a 36 letter alphabet
D) Extension of an earlier cipher called ADFGX
, Homophonic Substitution Correct Answer - A) One of the earlier
attempts to make substitution ciphers more robust by masking the letter
frequencies. Plain text letters map to more than 1 cipher text symbol
B) Having a single character of plain text map to more than 1 character of
cipher text makes it more difficult to analyze homophonic substitution
ciphers.
C) The nomenclator combined a codebook that had a table of homophonic
substitutions
D) Originally the codebook used names of poeple, thus the term "nomenclator.
Example *Mr. Smith could be XX, and Mr. Jones could be XYZ*
Null Ciphers Correct Answer - A) message is hidden in unrelated text.
Example *sending a message like "We are having breakfast at noon at the cafe.
Would that be ok?"*
B) Sender and recipient have prearranged to use a pattern, taking letters from
the message. Example *3, 20, 22, 27, 32, 48* would produce the word "attack"
Rail Fence Ciphers Correct Answer - A) May be the most widely known
transposition cipher.
B) You take down the message you want to encrypt and alter each letter on a
different row
Example* The message "Attackatdawn" or "Attack at dawn" is written as
Atcadw
taktan*
C) Next you take it and write it out from left to right
Example *Atcadwtaktan*
D) To decrpyt, reverse the steps
E) Most texts use two rows, but it can be done with any number of rows
The Enigma Machine Correct Answer - A) In World War II, the Germans
made use of an electromechanical rotor based cipher system known as The
Enigma Machine
B) Designed so that when the operator pressed a key the encrypted cipher
text for that plain text was different each time
Example *When the operator pressed the "A" key, it might generate an "F" this
time, and might generate a "D" next time*
C) Multi-alphabet cipher consisting of 26 possible alphabets
