# What are the principle of Symmetric Cipher in Information Security?

A symmetric cipher is one that uses the similar key for encryption and decryption. The use of a symmetric cipher presents the well-known challenge of how to share the secret key between the parties fast, as an unauthorized party to the communication can prevent it and eavesdrop on future communication.

There are various principles of Symmetric Cipher which are as follows −

• Plaintext − This is the authentic intelligible message or information that is full into the algorithm as input.

• Encryption algorithm − The encryption algorithm implements several substitutions and conversion on the plaintext.

• Secret key − The secret key is also input to the encryption algorithm. The key is a value autonomous of the plaintext and of the algorithm. The algorithm will create a multiple output based on the definite key being utilized at the time. The exact substitutions and conversion implemented by the algorithm depend on the key.

• Cipher text − This is the chaotic news created as output. It is based on the plaintext and the secret key. For a given message, there are two different keys will create two different cipher texts. The cipher text is a seemingly random flow of information and as it stands is unintelligible.

• Decryption algorithm − This is basically the encryption algorithm run in opposite. It takes the cipher text and the secret key and creates the initial plaintext.

There are two requirements for secure use of conventional encryption which are as follows −

• It is required a strong encryption algorithm. At a minimum, it is an algorithm to be such that an opponent who understand the algorithm and has access to one or more cipher texts would be inadequate to decipher the cipher text or consider the key.

This requirement is generally defined in a stronger form. The opponent should be inadequate to decrypt cipher text or find the key even if it is in possession of multiple cipher texts together with the plaintext that make each cipher text.

• Sender and receiver should have obtained copies of the secret key in a secure fashion and should maintain the key secure. If someone can find the key and understand the algorithm, all communication utilizing this key is readable.

This characteristics of symmetric encryption is what creates it feasible for widespread use. The fact that the algorithm use not be kept secret means that manufacturers can and have developed inexpensive chip implementations of data encryption algorithms.

These chips are broadly available and incorporated into a multiple products. With the use of symmetric encryption, the principal security issues is supporting the secrecy of the key. For this reason key is sent to the receiver through an independent secure channel. Moreover, a trusted third party can make the key and assign this to both source and destination.

Updated on: 11-Mar-2022

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