8/25/26, 1:53 PM ECS1601 SUMMARY flashcard sets | Quizlet
EC Council CES Flash Cards
Atbash Cipher
Invented by the Hebrew. Single substitution monoalphabetic cipher that substitutes each
letter with it's reverse (a and z, b and y, etc).
Caesar Cipher
Monoalphabetic cipher where letters are shifted one or more letters in either direction.
ROT 13
Monoalphabetic cipher that shifts characters 13 characters. Stands for Rotate 13. A would
become N, B would become O, etc.
Scytale Cipher
Was a staff with papyrus or letter wrapped around it so edges would line up. There would
be a stream of characters which would show you your message. When unwound it would
be a random string of characters. Would need an identical size staff on other end for other
individuals to decode message.
Multi-Alphabet Substitution Cipher
Doing something like +1, -2, +3 and shifting each character a different amount to the left
or right. For example, doing +1, -2, +3 with dog would results in emj.
Cipher Disks
A disk you rotated to encrypt/decrypt. Created by Leon Alberti. Similar technologies were
used in the Enigma machine. Considered the forefather of modern encryption.
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Vigenere Cipher
Invented by Giovan Battista Bellaso in middle 1553. Vigenere created a stronger version
of the cipher. Combining/Weaving Caesar cipher. Not cracked until late 1800s. It is a
cipher square with A to Z across all the columns and rows. You then use a keyword to
encrypt the message. For example, if the message is cat, and the keyword is horse, you
would look up where c and h intersect on the table (which is j), then where a and o
intersect (o) and t and r (k). Cat would then be encrypted as jok.
Playfair Cipher
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.
ADFGVX Cipher
Invented by Colonel Fritz Nebel in 1918. It is a 6x6 grid with ADFGVX at the top of each
column and beginning of each row. The 26 letters and numbers 0-10 are placed randomly
on the table. You then replace each character of your message with two characters which
are represented by the column followed by the row each character is present in.
Enigma Machine
Invented between World Wars, used by Germans and Japanese. Data could be
transmitted both via radio or printed on paper. Designed so that when a key was pressed,
the cipher text for that plain text was different each time. Was a multi-alphabet cipher with
26 possible alphabets.
Kerckhoff's Principle
We can expose everything but the private key and the data can still be secure.
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Issue with Symmetric Encryption
There's only one key, and it's difficult to only have both parties who need the key to have
it. It typically needs to be sent via another medium than the message or else it could be
compromised by the attacker. Keys can also be sent via out of band (off the network
being used to send the message).
Binary Math
Base 2 system instead of base 10 system.
Binary AND
If both numbers have a one in the same place, then the resultant number is a one. If not
then it is a zero
1st number - 1100
2nd number - 0100
--------------------------
Result - 0100
Binary OR
Checks to see if there is a one in either or both numbers in the same place. If so, the
resultant number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
--------------------------
Result - 1100
Binary XOR (Exclusive OR) ⊕
Checks to see if there is a one in either number in the same place. If so, the resultant
number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
--------------------------
Result - 1000
XOR is reversible. If you XOR the result with the 2nd number, you will get the 1st number
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EC Council CES Flash Cards
Atbash Cipher
Invented by the Hebrew. Single substitution monoalphabetic cipher that substitutes each
letter with it's reverse (a and z, b and y, etc).
Caesar Cipher
Monoalphabetic cipher where letters are shifted one or more letters in either direction.
ROT 13
Monoalphabetic cipher that shifts characters 13 characters. Stands for Rotate 13. A would
become N, B would become O, etc.
Scytale Cipher
Was a staff with papyrus or letter wrapped around it so edges would line up. There would
be a stream of characters which would show you your message. When unwound it would
be a random string of characters. Would need an identical size staff on other end for other
individuals to decode message.
Multi-Alphabet Substitution Cipher
Doing something like +1, -2, +3 and shifting each character a different amount to the left
or right. For example, doing +1, -2, +3 with dog would results in emj.
Cipher Disks
A disk you rotated to encrypt/decrypt. Created by Leon Alberti. Similar technologies were
used in the Enigma machine. Considered the forefather of modern encryption.
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,8/25/26, 1:53 PM ECS1601 SUMMARY flashcard sets | Quizlet
Vigenere Cipher
Invented by Giovan Battista Bellaso in middle 1553. Vigenere created a stronger version
of the cipher. Combining/Weaving Caesar cipher. Not cracked until late 1800s. It is a
cipher square with A to Z across all the columns and rows. You then use a keyword to
encrypt the message. For example, if the message is cat, and the keyword is horse, you
would look up where c and h intersect on the table (which is j), then where a and o
intersect (o) and t and r (k). Cat would then be encrypted as jok.
Playfair Cipher
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.
ADFGVX Cipher
Invented by Colonel Fritz Nebel in 1918. It is a 6x6 grid with ADFGVX at the top of each
column and beginning of each row. The 26 letters and numbers 0-10 are placed randomly
on the table. You then replace each character of your message with two characters which
are represented by the column followed by the row each character is present in.
Enigma Machine
Invented between World Wars, used by Germans and Japanese. Data could be
transmitted both via radio or printed on paper. Designed so that when a key was pressed,
the cipher text for that plain text was different each time. Was a multi-alphabet cipher with
26 possible alphabets.
Kerckhoff's Principle
We can expose everything but the private key and the data can still be secure.
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, 8/25/26, 1:53 PM ECS1601 SUMMARY flashcard sets | Quizlet
Issue with Symmetric Encryption
There's only one key, and it's difficult to only have both parties who need the key to have
it. It typically needs to be sent via another medium than the message or else it could be
compromised by the attacker. Keys can also be sent via out of band (off the network
being used to send the message).
Binary Math
Base 2 system instead of base 10 system.
Binary AND
If both numbers have a one in the same place, then the resultant number is a one. If not
then it is a zero
1st number - 1100
2nd number - 0100
--------------------------
Result - 0100
Binary OR
Checks to see if there is a one in either or both numbers in the same place. If so, the
resultant number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
--------------------------
Result - 1100
Binary XOR (Exclusive OR) ⊕
Checks to see if there is a one in either number in the same place. If so, the resultant
number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
--------------------------
Result - 1000
XOR is reversible. If you XOR the result with the 2nd number, you will get the 1st number
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