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Mostly for performance - symmetric encryption is much much faster (order of magnitudes) than asymmetric encryption.
Mostly for performance - symmetric encryption is much much faster (order of magnitudes) than asymmetric encryption.
PKI must use asymmetric encryption because it is managing the keys in many cases. This implies the use of public and private key pairs, which is asymmetric.
You can actually use both; the problem with symmetric encryption is how to get the shared key to someone else in a secure manner.The problem with asymmetric encryption is that it is too slow to be used to general communications.So, using both can solve the problems of drawbacks to just using one or the other.
Symmetric cryptography uses the same secret (private) key to encrypt and decrypt its data whereas asymmetric uses both a public and private key. Symmetric requires that the secret key be known by the party encrypting the data and the party decrypting the data. Asymmetric allows for distribution of your public key to anyone with which they can encrypt the data they want to send securely and then it can only be decoded by the person having the private key. This eliminates the need of having to give someone the secret key (as with symmetric encryption) and risk having it compromised. The issue with asymmetric is that it is about 1000 times slower than symmetric encryption which makes it impractical when trying to encrypt large amounts of data. Also to get the same security strength as symmetric, asymmetric must use strong a stronger key than symmetric. If you do a quick search on the differences between symmetric and asymmetric you can find many more explanations. This just a quick overview.
If you are using an encrypted channel, then at some point everyone uses symmetric encryption. It is fast (compared to asymmetric).The first part of an encrypted conversation will probably use asymmetric encryption to provide the shared private key that is later on used for the bulk part of data conversations on an encrypted channel.
Symmetric encryption requires one key known by both parties. Asymmetric encryption uses two keys, one encryption key known publicly and one decryption key known only by the recipient.Or more simply put,YesA public and private key
Asymmetric
From another user: Symmetric cryptography uses the same secret (private) key to encrypt and decrypt its data whereas asymmetric uses both a public and private key. Symmetric requires that the secret key be known by the party encrypting the data and the party decrypting the data. Asymmetric allows for distribution of your public key to anyone with which they can encrypt the data they want to send securely and then it can only be decoded by the person having the private key. This eliminates the need of having to give someone the secret key (as with symmetric encryption) and risk having it compromised. The issue with asymmetric is that it is about 1000 times slower than symmetric encryption which makes it impractical when trying to encrypt large amounts of data. Also to get the same security strength as symmetric, asymmetric must use strong a stronger key than symmetric.
Symmetric
"Evaluating cryptography is difficult since without 'breaking' the encryption its hard to say whether one encryption is better or not. Pretty Good Encryption (PGP) is asymmetric, that is the encryption and decryption keys are different which may give it an edge on symmetric encryption."
No, it could be another asymmetric relation.