Explanation

RC4

https://en.wikipedia.org/wiki/RC4

RC4 (Rivest Cipher 4 also known as ARC4 or ARCFOUR meaning Alleged RC4, see below) is a stream cipher. While it is remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, rendering it insecure. It is especially vulnerable when the beginning of the output keystream is not discarded, or when nonrandom or related keys are used. Particularly problematic uses of RC4 have led to very insecure protocols such as WEP.

The key-scheduling algorithm is used to initialize the permutation in the array " S " . " keylength " is defined as the number of bytes in the key and can be in the range 1 ≤ keylength ≤ 256, typically between 5 and 16, corresponding to a key length of 40 – 128 bits. First, the array " S " is initialized to the identity permutation. S is then processed for 256 iterations in a similar way to the main PRGA, but also mixes in bytes of the key at the same time.

Asymmetric

Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be openly distributed without compromising security.

Fibonacci Sequence

https://en.wikipedia.org/wiki/Fibonacci_number

In mathematics, the Fibonacci numbers, commonly denoted Fn, form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is,

F0 = 0, F1=1, Fn = Fn-1 + Fn-2; for n > 1.

The beginning of the sequence is thus:

0,1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144…

Explanation

Nonce

https://en.wikipedia.org/wiki/Cryptographic_nonce

A nonce is an arbitrary number that can be used just once in a cryptographic communication. It is similar in spirit to a nonce word, hence the name. It is often a random or pseudo-random number issued in an authentication protocol to ensure that old communications cannot be reused in replay attacks.

Global deduction

https://en.wikipedia.org/wiki/Cryptanalysis

Global deduction — the attacker discovers a functionally equivalent algorithm for encryption and decryption, but without learning the key.

Explanation

Lucifer

https://en.wikipedia.org/wiki/Lucifer_(cipher)

Lucifer was a direct precursor to the Data Encryption Standard. One version, alternatively named DTD-1.

Explanation

Brute force

https://en.wikipedia.org/wiki/Brute-force_attack

Brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct one is found. Alternatively, the attacker can attempt to guess the key which is typically created from the password using a key derivation function. This is known as an exhaustive key search.

Explanation

64

https://en.wikipedia.org/wiki/Skipjack_(cipher)

Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds.

Integrity. In information security, data integrity means maintaining and assuring the accuracy and completeness of data over its entire lifecycle. This means that data cannot be modified in an unauthorized or undetected manner.

An important application of hashes is verification of message integrity. Comparing message digests (hash digests over the message) calculated before, and after, transmission can determine whether any changes have been made to the message or file.

SHA-1

https://en.wikipedia.org/wiki/SHA-1

SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered as a hexadecimal number, 40 digits long. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard.