# Questions On Symmetric Cipher And Encryption Algorithms

1185 Words Sep 25th, 2015 5 Pages
2.1 Answer: Symmetric cipher has main five ingredients, that are as follows
1. Plaintext: This is the original message or data that has to be encrypted. This is in the meaningful format so anyone can read it. Plaintext is given as input to the encryption algorithm.
2. Encryption algorithm: This algorithm takes plaintext and key as input and performs various substitutions and transformation on the input and gives cipher text as output.
3. Cipher text: This is the scrambled message which has no meaning and cannot be decoded to the original message without prior knowledge of key and algorithm.
4. Secret key: This key is confidential and input to the encryption and decryption algorithms to encrypt and decrypt the data.
5. Decryption algorithm: This algorithm is present at the receiver side which functions totally reverse to the encryption algorithm and generates the plaintext from the input of cipher text and the key.

2.2 What are the two basic functions used in encryption algorithms?
Answer: there are two main principles that are used to encrypt the plaintext
1. Substitution: In substitution each element in the plaintext is substituted with another element. In this elements may be single, pair of letters, triplets of letters, mixture of above or so forth. At the decryption side receiver performs the inverse of the substitution.
2. Transposition: transposition cipher is a method of encryption by which the positions held by units of plaintext (which are commonly characters or…