Certified Encryption Specialist
Questions and Answers 100% Pass
Cryptography ✔✔The science of altering communication so that it cannot be understood without
having a key.
Caesar Cipher ✔✔Simple cipher that uses shifting letters.
Atbash ✔✔Used by Hebrews, cipher that reverses the alphabet.
ROT13 ✔✔Cipher that rotate or shifts by 13 letters.
Scytale ✔✔Cylinder tool used to encrypt and decrypt plaintext using a cloth or piece of leather
wrapped around a rod.
Vigenere Cipher ✔✔Most common multi-alphabetic cipher.
Symmetric Encryption ✔✔Same key is used to Encrypt and Decrypt plaintext.
Also known as Single Key Encryption.
,Diffusion ✔✔Changes to one letter in plaintext changes multiple characters of the ciphertext.
Confusion ✔✔Makes the relationship between the statistical frequencies of the ciphertext and
the actual key as complex as possible.
Avalanche ✔✔A small change in the input yields a large change in the output.
Complete Avalanche ✔✔A change in one bit of the plaintext affecting all bits in the ciphertext.
Kerckhoffs Principle ✔✔The crypto system should be secure if everything about the system,
except the key, is publicly known.
Substitution ✔✔Changing some part of the plaintext for some matching part of the ciphertext.
Transposition ✔✔Swapping of blocks of ciphertext.
Binary ADD ✔✔Stack both binary numbers; If both numbers are 1 then it's 1, otherwise it's 0.
,Binary OR ✔✔Stack both binary numbers; If either is a 1 then it's 1, otherwise it's 0.
Binary XOR ✔✔Stack both binary numbers; If their is a 1 in one number but not the other then
it's a 1, otherwise its 0.
This is reversible.
Block Cipher ✔✔Encrypts the information in blocks.
Stream Cipher ✔✔Encrypts the information one bit at a time.
DES ✔✔Data Encryption Standard
DES (Characteristics) ✔✔Made by IBM in 1970's.
64 bit Block Cipher.
56 Bit Key.
Uses Feistal Cipher.
, Feistal Function ✔✔64 Bits split Left and Right, Round function to one side, XORed with the
other side then sides are Transposed or switched.
Then continued for a set number of rounds.
Unbalanced Feistal Function ✔✔Same as Feistal but the 64 bits are not equally split.
Skipjack uses the Unbalanced Feistal Function.
3DES ✔✔Uses Data Encryption Standard with a key bundle. Three 56 bit keys are used to
encrypt with key 1, decrypt with key 2 and then encrypt with key 3.
DESx ✔✔Same as Data Encryption Standard but the plaintext is XORed with the key then
encrypted.
Is not more secure since the key space is still the same.
Whitening ✔✔The process of XORing in an additional key at any time in the encryption process.
AES ✔✔Advanced Encryption Standard
Questions and Answers 100% Pass
Cryptography ✔✔The science of altering communication so that it cannot be understood without
having a key.
Caesar Cipher ✔✔Simple cipher that uses shifting letters.
Atbash ✔✔Used by Hebrews, cipher that reverses the alphabet.
ROT13 ✔✔Cipher that rotate or shifts by 13 letters.
Scytale ✔✔Cylinder tool used to encrypt and decrypt plaintext using a cloth or piece of leather
wrapped around a rod.
Vigenere Cipher ✔✔Most common multi-alphabetic cipher.
Symmetric Encryption ✔✔Same key is used to Encrypt and Decrypt plaintext.
Also known as Single Key Encryption.
,Diffusion ✔✔Changes to one letter in plaintext changes multiple characters of the ciphertext.
Confusion ✔✔Makes the relationship between the statistical frequencies of the ciphertext and
the actual key as complex as possible.
Avalanche ✔✔A small change in the input yields a large change in the output.
Complete Avalanche ✔✔A change in one bit of the plaintext affecting all bits in the ciphertext.
Kerckhoffs Principle ✔✔The crypto system should be secure if everything about the system,
except the key, is publicly known.
Substitution ✔✔Changing some part of the plaintext for some matching part of the ciphertext.
Transposition ✔✔Swapping of blocks of ciphertext.
Binary ADD ✔✔Stack both binary numbers; If both numbers are 1 then it's 1, otherwise it's 0.
,Binary OR ✔✔Stack both binary numbers; If either is a 1 then it's 1, otherwise it's 0.
Binary XOR ✔✔Stack both binary numbers; If their is a 1 in one number but not the other then
it's a 1, otherwise its 0.
This is reversible.
Block Cipher ✔✔Encrypts the information in blocks.
Stream Cipher ✔✔Encrypts the information one bit at a time.
DES ✔✔Data Encryption Standard
DES (Characteristics) ✔✔Made by IBM in 1970's.
64 bit Block Cipher.
56 Bit Key.
Uses Feistal Cipher.
, Feistal Function ✔✔64 Bits split Left and Right, Round function to one side, XORed with the
other side then sides are Transposed or switched.
Then continued for a set number of rounds.
Unbalanced Feistal Function ✔✔Same as Feistal but the 64 bits are not equally split.
Skipjack uses the Unbalanced Feistal Function.
3DES ✔✔Uses Data Encryption Standard with a key bundle. Three 56 bit keys are used to
encrypt with key 1, decrypt with key 2 and then encrypt with key 3.
DESx ✔✔Same as Data Encryption Standard but the plaintext is XORed with the key then
encrypted.
Is not more secure since the key space is still the same.
Whitening ✔✔The process of XORing in an additional key at any time in the encryption process.
AES ✔✔Advanced Encryption Standard
