WGU C839 Cryptography. Exam Review Questions and answers, rated A+

WGU C839 Cryptography. Exam Review Questions and answers, rated A+ Kerckhoff's Principle A cryptosystem should be secure even if everything about the system, except the key, is public knowledge. Opposite of security by obscurity Modern Cryptographic Algorithm Types Asymmetric and Symmetric; Combine substitution and transposition Symmetric Cryptography Encryption that uses a single key to encrypt and decrypt a message Major issue is key exchange C=E(k,p) P=D(k,c) Cryptographic Substitution Changing some part of the plaintect for a matching part of the ciphertext. All historical examples of crytpographic algorithms algorithms fall into this category. Cryptographic Transposition The swapping of blocks of ciphertext. Binary OR Asks if there is a 1 in the first number of the second number, or in both, and returns a 1 if TRUE 1101 0110 1111 (result of OR) Binary AND Asks if there is a 1 in both the numbers and returns a 1 if TRUE 1101 0110 0100 (result of AND) TERM Binary XOR DEFINITION Asks if there is a 1 in first