Types of Encryption

Symmetric (algorithm)	Asymmetric (algorithm)
Secret-key encryption	Public-key encryption
1 key (encrypts & decrypts)	2 keys - Public (encrypts) & Private (decrypts)
Generally fast	Somewhat slower
Security is hard to guarantee	Secure

Symmetric

Symmetric encryption (a.k.a. secret-key encryption) means the same key is used to encrypt and decrypt data. It is very easy to use, and usually very fast too. On the other hand, symmetric encryption keys must be kept secure - you would need to make sure each person who needs the key gets it without any risk of compromise.



Asymmetric

Asymmetric encryption (a.k.a. public-key encryption) means that you have one key for encryption (a public key) and another key for decryption (a private key). The public key can be given away freely to whoever wants it - with the public key data cannot be read, a private key is also needed to decrypt your data.

For example, if you sent out the public key to everyone who sends email to you, they would all be able to send you encrypted emails that only you would be able to decrypt and read.

Asymmetric encryption is generally slower than symmetric encryption. However, the public keys are safe to publish anywhere (even on the Internet) because to get the private key from a public key would require hundreds of years of brute force work.