Introduction to Cryptography - D334

Introduction to Cryptography - D334 12 studiers in 3 days (2 reviews) Students also studied Terms in this set (250) Western Governors UniversityD 333 Save C839v5/D334 Additional Practice Teacher 165 terms ShawnD_Preview C839v5/D334 Algorithms Drill Teacher 51 terms ShawnD_Preview Pre-Assessment Intro to Cryptograp...60 terms Sandy_T9Preview WGU C 1,037 ter Wie XOR the following

0101110101010111

1001100000111010

------------------

1100010101101101

asymmetric key-based encryption -typical methods RSA DSA El Gamal Symmetric key-based encryption -Typical Methods RC2- 40 bit key size 64 bit block RC4- (Stream Cipher)- Used in SSL and WEP RC5- (Variable Key size, 32, 64, or 128 bit block size) AES- (128, 192 or 256 bit key size, 128 bit block size) DES- (56 bit key size. 64 bit Block size) 3DES- (112 bit key size, 64 bit block size) Block EncryptionRC2(40 bit key size) RC5(Variable block size) IDEA DES 3DES AES (Rijndael) Blowfish twofish stream encryptionRC4 Chacha

Rainbow AttackThe method of knowing the mapping between the hashed values and the original data Dictionary-type attacka brute force analysis ∉does not belong to when an object is not in a set ∈Belongs to when an object is within a set ⊆subset subset has fewer elements or equal to the set A ∪ Bunion (objects that belong to set A or set B) |such that

A ∩ BIntersection: in both A and B

Enigma Machine -Cypher 10Used a polyalphabetic substitution cipher, which did not repeat within a reasonable time period, along with a secret key. For the cracking of the Enigma cipher, the challenge was thus to determine both the algorithm used and the key.Enigma's main weakness, though, was that none of the plain text letters could be ciphered as itself.Four-square cipher9Uses four 5 × 5 matrices arranged in a square, are where each matrix contains 25 letters for encoding and decoding operations.One-time pad cypher8Cypher Code mapping that is only used once.

Advantage: it is essentially unbreakable.

Disadvantage: it takes lots of work as you would have to generate the pad to be

used, each time.Vigenere Cipher 7Polyalphabetic cipher that involves using a different mapping, based on a keyword, for each character of the cipher. An advantage of this type of cipher is that the same plaintext character is likely to be coded to different mappings, depending on the position of the keyword, making guessing more difficult.Ceasar Cipher6Mono-alphabetic substitution cipher known as "shift" cipher. Involves plaintext being replaced by a letter some fixed number of positions down the alphabet. i.e., a Caesar Cipher using a shift of +3 would mean a plaintext letter A would result in a ciphertext letter D (a shift of three positions to the right in the alphabet) Morse Code cipher 5Encoding method, rather than a cipher, that works by translating characters into sequences of dots (.) and dashes (-) Playfair Cipher 45 × 5 matrix containing the alphabet less the letter J. Cipher/decipher process consists of a set of rules outlining use of column and row combinations.

BIFID Cipher 3Makes use of a grid and which maps the letters into numeric values.Rail Code Cipher 2Employs a method to scramble text by writing it in a sequence across a number of rails.Pig Pen Cipher 1Mono- alphabetic substitution cipher that makes use of mapping plaintext characters to graphical characters rather than to alphabetic ones. i.e. A=(pick a

symbol), vs A=(pick a letter). Disadvantage: once the mapping is known, it is

difficult to keep the message secret.Encryptionin simplest terms is changing plaintext into ciphertext DecryptionThe process of converting a ciphertext into plaintext.AESCryptEncrypt individual files and encrypt full disks with options such as Bitlocker and FileVault Mono-alphabeticc code or substitution is where a single mapping from our alphabet to a cipher alphabet is created. Many early cryptosystems used this.Polyalphabeticrefers to the mapping of our alphabet to a number of cipher alphabets. This approach added a bit of complexity to early cryptosystems.One-time padis considered to be unbreakable since it only uses its cipher code once.Pseudo-Random Number Generators (PRNGs) This method repeats the random numbers after a given time (periodic). They are fast and are also deterministic and are useful in producing a repeatable set of random numbers.Frequency Analysisis cipher cracking methodology that involves identifying patterns and variations in the probability of codes. i.e. a three-letter ciphered text combination spotted at the beginning of a string too often could tip us off that those three letters correlate the letters THE in the English alphabet.True Random Number Generators (TRNGs)This method generates a true random number and uses some form of random process. One approach is to monitor the movements of a mouse pointer on a screen or from the pauses between keystrokes. Overall, the method is generally slow, especially if it involves human interaction, but is non-deterministic and aperiodic.Entropymeasures level of unpredictability; in encryption relates to the degree of uncertainty of the encryption process.ASCII8-bit values, up to 256 characters UTF-1616- bit values, up to 65,536 characters Hardware vs Software encryptionHardware encryption is more efficient than software encryption.

Hardware Security Module (HSM)is a tamper-evident and intrusion-resistant physical device that safeguards and manages cryptographic keys and provides cryptographic processing.Trusted Platform Module (TPM)is a dedicated processor that handles hardware-level encryption; allows the use of full disk encryption on a hard drive in a manner that minimizes the impact on system performance. TPM contains the encryption keys.Combination vs. Permutationcombinations = not concerned with the order//permutations = all options considered including sequence.Secret Keyencryption (symmetric Cryptography) makes use of a single secret key for both encryption and decryption.Diffie-Hellmanis a widely used key exchange algorithm used to exchange the secret key in symmetric cryptography.Two types of symmetric encryptionblock and stream Symmetric block encryption-involves grouping data into blocks and encrypting the individual blocks -padding is used to fill blocks to operating size when the data does not fit perfectly.symmetric stream encryption-involves encrypting one bit at a time, i.e., a synchronous stream -is often much faster than block and can typically be applied in real-time applications.Symmetric block ciphers-manage how blocks of data are processed through block cipher mode implementations. For instance, one may choose to use the DES block cipher configured with ECB as the mode of operation.Common Block Cipher ModesElectronic Code Book (ECB) Cipher Block Chaining (CBC) Cipher Feedback (CFB) Output Feedback (OFB) Counter (CTR) Mode CFB, OFB, CTRimplementations essentially allow the block cipher to operate like a stream cipher.Saltingthe process of adding an initialization vector to the ciphering process to change its operation and ensure that the ciphertext does not give the original plaintext when played back.Work FactorThis represents the time and effort required to break a cryptography system.