INTECH 3201 sir cenon 1st term exam 3rd year 2nd sem

it is an art of communication between two users via coded message

cryptography

it is a process of scrambling data into a code that can onlyb be decoded with a key

encryption

it is the original representation of the information

plain text

the encoded version of the information

ciphertext

a unique digital key that unlocks the code

encryption key

the process of urning cipher text into plaintext

DECRYPTION

earliest written evidence of encryption can be found to ancient ____ nearly _____ BC

egypt nearly 4000BC

it contained a script recording his deeds in life

tom of Khnumhotep 2

first recorded instances of encyption being used for military is around____ BC

500BC

Spartan encryption used in invention called___

scytale

it allowed secret message to sent and recieved

scytale

it has electromehcanical rotor mechanism that scrambles the 26 letters form the alphabet

world war 2 (ENIGMA)

when did the data encryption become popular?

earl 1970s

why did the data encryption become popular?

because of expensive comuters and need for information retention

who named after the RSA?

Ron Rivest
Adi Shamir
Leonard Adleman

it introduced the concpt of a publi-proivate key pair for encryption

RSA

give the principles of cryptography?

CIANK
Confidentiality
Integrity
Authentiction
Non-repudiation
Key management

to keep data safe so that information stays private and secure

confidentiality

it means ensuring taht our data in transit or after recieving is intact or not

Integrity

the ability to make sure that data or information has not been changed or modified with

Integrity

it is the process of validating the identity of a user or device

Authentiction

a method of stopping a person from denying that he or she has committed a particular act or crime

Non-repudiation

it is the process of creating, distributing, and managing cryptographic keys

Key managemnet

give the 2 main types fo cryptographic systems

Symmetric
Asymmertic

it uses a single key for both encryption and decryption.

Symmetric encryption

give an examples of symmetric encryption

DES, 3DES, AES

DES means?

Data ENcryption Standard

it is a 56 bit key encryption method, now consider as weak

DES

it is an improved version of DES that apply encryption 3 times

3DES

AES stands for?

Advanced Encryption standard

it is awidely used and highly secure algorithm with key sizes of 128, 192, 256 bits

AES

advatages of symmetric encryption

-Fast and efficient for large amount of data
-less computational power

disadvantages of symmetric encryption

security

it is also known as public-key cyptography

asymmetric encryption

2 keys of asymmetric encrytption

-Public key (used for encryption)
-private key (Used for decryption)

_____ shared opnely, while the ____ key is kept secret

Public key_private key

examples of asymmetric encryption

RSA

ECC - Eliptic curve cyrptography

a woiely used encryption algorithm often used for securing online transactions and emails

RSA

a more effiecinet alternative to RSA used in mobile and IOT

ECC - Elliptic Curve Cryptography

giv the 2 types of cipher

stream cipher and the block cipher

it is an encryption technique that works byte by byte to transform plain text into code thats unreadable to anyone wihout the proper key

Strem Cipher

it takes a block of plaintext bits and generate a block of ciphertext bits, generally of same size

Block cipher

t or f
DES is a stream cipher

false
it is a block cipher

original size of DES

64 bits

t or f

ES was never cryptographically broken, but its key length is too short by nowadays standards and it could be brute forced with some effort.

true

the DES orgin date was?

1972

DES year dveloped was in ?

1971

_____ is based on the Feistel block cipher called _____

DES
Lucifer

DES is developed by IBM researcher:

Horst Feistel

DES was approved on _____ and got dominance came to an end in ____

November 1976
2002

it takes 64 bit plain text and turns into 64 bit cyphertext

DES Algorithm Steps

it is based the original data encryption standard (DES)

3DES

it is a symmetric block cipher chosen by the US government to protect classified information

AES
Advanced Encryption Standards

AES also known as …

Rijndael [reindal]

AES develoed by two belgian cryptographers namely…

Joan Daemen
Vincent Rijmen

_____ is a family of cipherss with different key and block sizes

Rijndael

it is based on a design prionciple known as a substitution-permutation netwrok, and it efficient in both software and hardware

AES

t or f
AES also use Feistel network

false- AES does not used Feistel network

it operates on 4×4 column-major order array of 16 bytes

AES

round keys are derived from the cipher key using the EAS key scheule. AES requires a separate 128 bit round key block for each round plus one more

Key Expansion

it is a non linear substitution steps where each byte is replaced with another according to lookup table

SubBytes

a transposition step where the last three rows of the state are shifted cyclically a certain number of steps

ShiftRows

a linear mixing operations which operates on the columns of the state, sombining the four bytes in each column

MixColumn

each byte of the state is combined with a byte of the round subkey using the XOR operation

AddRoundKey

it is one of the oldest widely used for secure data transmission

RSA

t or f

there is no published methods to defeat the system if a large enough key is used

True

t or f

RSA is relatively fast algorithm

false-
RSA is a relatively slow algorithm

the idea of an asymmetric public-private key cryptosystem is attributed to _____ and ______, who piblished the concept in 1976

Whitfield Diffie
Martin Hellman

4 steps of RSA Algorithm

key generation
key distribution
encryption
decryption

Rivest and shamir is ____, while Adleman is ____

Rivest and shamir is computer scientist , while Adleman is mathematician