Cryptology and Different Cipher Methods Flashcards
The process of making and using codes to secure the transmission of information
Cryptography
The process of obtaining the original message from an encrypted message without knowing the algorithms and keys used to perform the encryption
Cryptanalysis
The process of converting an original message into a form that is unreadable to unauthorized individuals
Encryption
The process of converting the cyphertext back into plaintext so that it can be understood
Decryption
The programmatic steps used to convert unencrypted message into an encrypted sequence of bits that represent the message
Algorithm
An encryption method or process encompassing the algorithm, key(s) or cryptovariable(s), a procedure used to perform encryption and decryption
Cipher or cryptosystem
The encoded message resulting from an encryption
Ciphertext or cryptogram
The process of converting components (words or phrases) of an encrypted message into encrypted components
Code
To decrypt
Decipher
To encrypt
Encipher
The information used in conjunction with an algorithm to create the ciphertext from the plaintext or derive the plaintext from the ciphertext
Key or cryptovariable
The entire range of values that can be used to construct an individual key
Keyspace
A series of encryptions and decryptions between a number of systems
Link encryption
The hiding of messages
Steganography
The amount of effort (usually in hours) required to perform cryptanalysis to decode an encrypted message when the key or algorithm (or both) are unknown
Work factor
Two methods of encryption plaintext
- Bit Stream Method
- Block Cipher Method
Commonly used algorithm functions is the exclusive OR (XOR) operation
Bit Stream Method
Use substitution, transposition, XOR, or some combination of these
Block Cipher Method
You substitute one value for another — for example, a letter in the alphabet with the letter three values to the right
Substitution Cipher
Replace a character/s with a different character/s based upon some key
Monoalphabetic substitution-based ciphers
Similar to monoalphabetic ciphers, except multiple alphabetic strings are used
Polyalphabetic Ciphers
A matrix of 26x26 alphabetic characters — used in encoding simple polyalphabetic ciphers
Polyalphabetic Ciphers
Also known as permutation cipher, it simply arranges the values within a block to create the ciphertext
Transposition Cipher
Also known as one-time pad cipher developed by AT&T, uses a set of characters only one time for each encryption process
Vernam cipher
The process of keeping a computer number within a specific range is called ____________
modulo
Algorithm is the mechanical process of looking the reference from the ciphertext and converting each reference to a work by using the ciphertext’s value and the key (the book)
Book or Running Key Cipher
Mathematical algorithms that generate a message summary or digest (sometimes called fingerprint) to confirm the identity of a specific message and to confirm that there have not been any changes to the content
Hash functions
Hash functions confirm message ____________ and ____________
identity… integrity
Hash algorithms are public functions that create a ____________ (message digest) by converting variable-length messages into a single fixed-length value
hash value
The message digest is a ____________ or the author’s message that is compared with the recipient’s locally calculated hash of the message
fingerprint
