Introduction to Cryptography - D334 Shawn C839v5/D334 All-In-One Study Guide

Introduction to Cryptography - D334 Shawn C839v5/D334 All-In-One Study Guide

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Students also studied Terms in this set (120) Western Governors UniversityD 333 Save C839v5/D334 Additional Practice Teacher 165 terms ShawnD_Preview C839v5/D334 Algorithms Drill Teacher 51 terms ShawnD_Preview Introduction to Cryptography - D33...250 terms Square_Bubble Preview Pre-Ass 60 terms San Practice questions for this set Learn1 / 6Study using Learn

Elliptic Curve which is often used in key exchange methods:

Changing plaintext into ciphertext (Should be applied in at rest and in transit) Encryption Changing ciphertext to plaintextDecryption Choose an answer

1HMAC2RSA

3AES4ECDH

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Encrypt individual files and full disks with options such as BitLocker and FileVault Aescrypt Mapping from our alphabet to a number of cipher alphabets.Added complexity in early cryptosystems.Polyalphabetic Single mapping from our alphabet to a cipher alphabet is created.Many early cryptosystems.Mono-Alphabetic Considered un-breakable since it only uses its cipher code once.One-Time Pad Method repeats the random numbers after a given time.(periodic) They are fast and deterministic.Useful in producing repeatable set of random numbers.Pseudo-Random Number Generators (PRNGs) 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.True Random Number Generators (TRNGs) 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.Frequency Analysis measures level of unpredictabilityEntropy Two common binary to characters encoding methods ASCII (8bit value, up to 256 characters) UTF-16 (16bit values, up to 65,536 characters)

• bit value, up to 256 charactersASCII

16 bit value, up to 65,536 charactersUTF-16 Tamper-evident and intrusion-resistant physical device that safeguards and manages cryptographic keys and provides cryptographic processing.Hardware Security Module (HSM) Which encryption is more efficient?Hardware

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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.Contains the encryption keys.Trusted platform module (TPM) value which only has factors of 1 and itselfPrime Number Determine the likelihood of an event happening, typically by understanding the chances of how each of the elements involved in an event interact, and the likelihood of them happening. >> Dependent, Independent, and mutually exclusive Probability Mono- 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.Pigpen

• × 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.Playfair Mono-alphabetic substitution cipher known as "shift" cipher. Involves plaintext being replaced by a letter some fixed number of positions down the alphabet. i.e., 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) Caesar Polyalphabetic 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.Vigenère Uses four 5 × 5 matrices arranged in a square, are where each matrix contains 25 letters for encoding and decoding operations.Four-square Cipher Used a polyalphabetic substitution cipher, which did not repeat within a reasonable time period, along with a secret key. For the cracking of the cipher, the challenge was thus to determine both the algorithm used and the key. Main weakness, though, was that none of the plain text letters could be ciphered as itself.Enigma Machine The issue with symmetric cryptography since the same key is used for encryption and decryption.Finding a secure way to share or transport the key between the entity encrypting and the one decrypting.

Widely used key exchange algorithm used to exchange the secret key in symmetric cryptography.Diffie-Hellman Two types of symmetric encryptionBlock & Stream Symmetric block encryption involves grouping data into blocks and encrypting the Individual Blocks symmetric stream encryption involves encrypting One bit at a time often much faster than block and can typically be applied in real-time applications.Symmetric stream encryption padding is used to fill blocks to operating size when the data does not fit perfectly symmetric block encryption essentially allow the block cipher to operate like a stream cipher CFB, OFB, and CTR Common block cipher modesECB, CBC, CFB, OFB, and CTR All current cipher codes are crackable and a measure of the security of a code is the amount of time it would take to break the code based on the computational power available. This is often referred to as the work factor. As processing power magnifies, security of current ciphers decreases True

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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 Salting Same ciphertext will be output EVERY TIME the same plaintext is encrypted.Each block is processed separately.Most basic, weak, and unsecure mode.Electronic Code Book (ECB) incorporation of an initialization vector for the first block.Results of encryption from previous block is XOR'd with plaintext of the current block. That result is input into to encryption process of the current block.Cipher Block Chaining (CBC)