What is an symmetric cryptography?

Answer 1

both parties share the same key to encrypt and decrypt

- Symmetric encryption means that an encrypted file can be decoded simply by reversing the way it was coded. If we consider it in terms of a padlocked box, the same key that was used to lock it, can be used to open it once again.

In terms of files this means that if you encrypt a file using a password, that same password can be used by anyone who knows it, to decrypt the data. The disadvantage of this is that whenever you encrypt a file and send it to someone, you must make sure that person also knows the password you used.

This is why asymmetric encryption exists whereby one person can encrypt and send a file to someone else using "public key cryptography". The short definition of this is that encrypted data is not decrypted in the same way which means that there is no need to have a prearranged password.

Answer 2

There are two general types of modern cryptography; symmetric cryptography and asymetric (also known as public key) cryptography. Symetric crypto is where both sides have the same shared encryption key, and that key is used to both encrypt and also decrypt any encrypted information. Symmetric crypto is more efficient (faster) than asymmetric crypto, but asymetric crypto works without having to share a key.

Answer 3

Symmetric-key algorithms are a class of algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of cipher text. The keys may be identical or there may be a simple transformation to go between the two keys. The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link. This requirement that both parties have access to the secret key is one of the main drawbacks of symmetric key encryption, in comparison to public-key encryption.