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Explain Symmetric & Asymmetric Encryption

The goal of secure communications is to hide, or encode, publicly exposed messages so that they can only be read by authorized recipients. Messages can be encoded, or encrypted, using symmetric or asymmetric techniques if the encryption keys used by the sender and recipient can be kept secret. An encryption key is a value that must be fed into an encryption algorithm, or set of rules, to decode an encrypted message.

Symmetric Encryption
- Symmetric encryption, also known as shared key encryption, is so-called because a single, shared key is used to encrypt and decrypt messages. Symmetric encryption can be likened to a combination lock protecting a safe; in the same way that a single combination protects the safe, so a single encryption key protects the messages. Essentially, messages are split into chunks, or blocks, and the encryption key is applied to each block to produce an encrypted version of the message, known as ciphertext.
Strengths &Weaknesses
- Symmetric encryption algorithms are typically simpler than asymmetric encryption algorithms. This means that they are fast, easy to implement and less reliant on computer resources, such as processor power and memory, but also easier to understand and break into, or crack. The principal weakness of symmetric encryption is that if an attacker compromises the encryption key, he can read all the messages encrypted with that key. This means that if hundreds of keys are distributed to users, they all need to be redistributed to maintain security if the key is compromised.
Asymmetric Encryption
- Asymmetric encryption, also known as public key encryption, is called such because two different keys, known as a public key and private key, are used to encrypt and decrypt data. Asymmetric encryption treats messages like enormous numbers, which are multiplied and divided to produce a remainder before being converted back into text.
Strengths &Weaknesses
- In asymmetric encryption, the only key that is ever distributed to recipients is the public key. The private key is never distributed, so it cannot be intercepted or compromised. Even if the private key is compromised by some means, only one pair of keys needs to be redistributed to maintain security. Asymmetric encryption is therefore inherently more secure than symmetric encryption, especially for large businesses conducting e-commerce transactions. The complexity of asymmetric encryption algorithms does, however, mean that they are slower and require more computer resources than symmetric encryption algorithms, which is reflected by increased hardware costs.

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