Week 1 : Course Introduction Flashcards
Cryptography
is a method of storing and transmitting data in a form that only those it is intended for can read and process.
Cryptography
A science of protecting information by encoding it into an unreadable format.
What i the ultimate goal of cryptography
The ultimate goal of cryptography is to hide information from unauthorized individuals,
A more realistic goal of cryptography is to make obtaining the information too work-intensive to be worth it to the attacker.
Today’s transmission mechanism of encrypted message
packets carrying 0’s and 1’s passing through network cables or open airwaves
What is atbash
.
Encryption method requiring the alphabet to be flipped so that each letter in the original alphabet is mapped to a different letter in the flipped alphabet
Cryptanalysis
is a science of studying and breaking the secrecy of encryption algorithms and their necessary pieces.
What is encryption?
Encryption is a method of transforming original data, called plaintext or cleartext, into a form that appears to be random and unreadable, which is called ciphertext.
what is cryptosystem
A system that provides encryption and decryption
what is keyspace
range of values that can be used to construct a key
What is work factor?
Is an estimate of the effort it would take an attacker to penetrate an encryption method.
What can Cryptosystems provide
Cryptosystems can provide confidentiality, authenticity, integrity, and nonrepudiation services.
Confidentiality
means that unauthorized parties cannot access information.
Authenticity
refers to validating the source of the message to ensure the sender is properly identified.
Integrity
provides assurance that the message was not modified during transmission, accidentally or intentionally.
Nonrepudiation
means that a sender cannot deny sending the message at a later date, and the receiver cannot deny receiving it
Cryptology
The study of both cryptography and cryptanalysis
Ciphertext
Data in encrypted or unreadable format
Encipher
Act of transforming data into an unreadable format
Decipher
Act of transforming data into a readable format
Key
Secret sequence of bits and instructions that governs the act of encryption and decryption
Key clustering
Instance when two different keys generate the same ciphertext from the same plaintext
Keyspace
Possible values used to construct keys
Plaintext
Data in readable format, also referred to as cleartext
Cryptography history
has roots that began around 2000 BC in Egypt when hieroglyphics were used to decorate tombs to tell the story of the life of the deceased.
When was the first system of encrypting information
Around 400 BC, the Spartans used a system of encrypting information by writing a message on a sheet of papyrus, which was wrapped around a staff.
Algorithm
Set of mathematical rules used in encryption and decryption
Breaking a key
has to do with processing an amazing
number of possible values in the hopes of finding the one value that can be used to decrypt a specific message
When was the first encryption?
Dated back to 4000 years ago
what is a packet?
A transmission mechanism
Root of Cryptography
Aroud 2000 DC
The rotor cipher machine,
Called Enigma, device that substitutes letters using different rotors within the machine
Who is the father of Cryptographie
William Friedman
Clipper Chip
Encryption method developed by law enforcement
The strength of the encryption method
comes from the algorithm, secrecy of the key,length of the key, initialization vectors, and how they all work together.
When strength is discussed in encryption, it refers to how hard it is to figure out the algorithm or key,
whichever is not made public.
brute force attack,
means trying every possible key value until the resulting plaintext is meaningful.
